Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity Schedule of Accumulated Other Comprehensive Income (Loss) (Details)

v2.4.1.9
Stockholders' Equity Schedule of Accumulated Other Comprehensive Income (Loss) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]    
Accumulated Other Comprehensive Income (Loss), Net of Tax $ 849,858us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax $ 855,789us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Collateralized Mortgage Backed Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Unrealized Gains 878,308two_AvailableForSaleSecuritiesUnrealizedGains
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesMember
891,820two_AvailableForSaleSecuritiesUnrealizedGains
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesMember
Available-for-sale Securities, Gross Unrealized Losses $ (28,450)two_AvailableForSaleSecuritiesUnrealizedLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesMember
$ (36,031)two_AvailableForSaleSecuritiesUnrealizedLosses
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesMember