Annual report pursuant to Section 13 and 15(d)

Fair Value of Financial Instruments (Details)

v2.4.1.9
Fair Value of Financial Instruments (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Repurchase agreements $ 12,932,463us-gaap_AssetsSoldUnderAgreementsToRepurchaseRepurchaseLiability $ 12,250,450us-gaap_AssetsSoldUnderAgreementsToRepurchaseRepurchaseLiability
Long-term Federal Home Loan Bank Advances 2,466,262us-gaap_FederalHomeLoanBankAdvancesLongTerm  
Maturity Over One Year [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Repurchase agreements $ 93,221us-gaap_AssetsSoldUnderAgreementsToRepurchaseRepurchaseLiability
/ us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis
= two_MaturityOverOneYearMember
$ 200,000us-gaap_AssetsSoldUnderAgreementsToRepurchaseRepurchaseLiability
/ us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis
= two_MaturityOverOneYearMember