Annual report pursuant to Section 13 and 15(d)

Derivative Instruments and Hedging Activities Schedule of Constant Maturity Swaps (Details)

v2.4.1.9
Derivative Instruments and Hedging Activities Schedule of Constant Maturity Swaps (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Derivative [Line Items]      
Derivative, Notional Amount $ 48,115,523invest_DerivativeNotionalAmount $ 37,366,610invest_DerivativeNotionalAmount $ 22,377,656invest_DerivativeNotionalAmount
Swap [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate   0.821%two_DerivativeAverageStrikeSwapRate
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Notional Amount 14,000,000invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
10,000,000invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
0invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
Derivative, Fair Value, Net   (3,773)us-gaap_DerivativeFairValueOfDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Cost   0two_DerivativeCost
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Unrealized Gains (Losses)   (3,773)two_DerivativeUnrealizedGainsLosses
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Swap [Member] | Determination Date, February 2014 [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate   0.768%two_DerivativeAverageStrikeSwapRate
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Notional Amount   3,000,000invest_DerivativeNotionalAmount
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Fair Value, Net   625us-gaap_DerivativeFairValueOfDerivativeNet
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Cost   0two_DerivativeCost
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Unrealized Gains (Losses)   625two_DerivativeUnrealizedGainsLosses
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Swap [Member] | Determination Date, March 2014 [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate   0.85%two_DerivativeAverageStrikeSwapRate
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Notional Amount   5,000,000invest_DerivativeNotionalAmount
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Fair Value, Net   (3,171)us-gaap_DerivativeFairValueOfDerivativeNet
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Cost   0two_DerivativeCost
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Unrealized Gains (Losses)   (3,171)two_DerivativeUnrealizedGainsLosses
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Swap [Member] | Determination Date, June 2014 [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate   0.828%two_DerivativeAverageStrikeSwapRate
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJune2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Notional Amount   2,000,000invest_DerivativeNotionalAmount
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJune2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Fair Value, Net   (1,227)us-gaap_DerivativeFairValueOfDerivativeNet
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJune2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Cost   0two_DerivativeCost
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJune2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Derivative, Unrealized Gains (Losses)   (1,227)two_DerivativeUnrealizedGainsLosses
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJune2014Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
 
Interest Rate Risk Associated with the Investment Portfolio [Member] | Swap [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate 0.548%two_DerivativeAverageStrikeSwapRate
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Notional Amount 14,000,000invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Fair Value, Net 1,530us-gaap_DerivativeFairValueOfDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Cost 0two_DerivativeCost
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Unrealized Gains (Losses) 1,530two_DerivativeUnrealizedGainsLosses
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Interest Rate Risk Associated with the Investment Portfolio [Member] | Swap [Member] | Determination Date, January 2015 [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate 0.538%two_DerivativeAverageStrikeSwapRate
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJanuary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Notional Amount 7,000,000invest_DerivativeNotionalAmount
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJanuary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Fair Value, Net 1,502us-gaap_DerivativeFairValueOfDerivativeNet
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJanuary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Cost 0two_DerivativeCost
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJanuary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Unrealized Gains (Losses) 1,502two_DerivativeUnrealizedGainsLosses
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateJanuary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Interest Rate Risk Associated with the Investment Portfolio [Member] | Swap [Member] | Determination Date, February 2015 [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate 0.572%two_DerivativeAverageStrikeSwapRate
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Notional Amount 2,000,000invest_DerivativeNotionalAmount
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Fair Value, Net (13)us-gaap_DerivativeFairValueOfDerivativeNet
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Cost 0two_DerivativeCost
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Unrealized Gains (Losses) (13)two_DerivativeUnrealizedGainsLosses
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateFebruary2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Interest Rate Risk Associated with the Investment Portfolio [Member] | Swap [Member] | Determination Date, March 2015 [Member]      
Derivative [Line Items]      
Derivative, Average Strike Swap Rate 0.552%two_DerivativeAverageStrikeSwapRate
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Notional Amount 5,000,000invest_DerivativeNotionalAmount
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Fair Value, Net 41us-gaap_DerivativeFairValueOfDerivativeNet
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Cost 0two_DerivativeCost
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember
   
Derivative, Unrealized Gains (Losses) $ 41two_DerivativeUnrealizedGainsLosses
/ two_DerivativeByDeterminationDateAxis
= two_DeterminationDateMarch2015Member
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_SwapMember
/ two_RiskTypeAxis
= two_InterestRateRiskAssociatedwiththeInvestmentPortfolioMember