Quarterly report pursuant to Section 13 or 15(d)

Schedule of Repurchase Agreements by Maturity (Details)

v3.5.0.2
Schedule of Repurchase Agreements by Maturity (Details)
$ in Thousands
Sep. 30, 2016
USD ($)
Dec. 31, 2015
USD ($)
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Interest Rate 1.06% 1.10%
Repurchase agreements $ 10,637,373 $ 5,008,274
Assets Sold under Agreements to Repurchase, Weighted Average Remaining Maturity 69 35
US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Interest Rate 0.79% 0.65%
Repurchase agreements $ 8,861,538 $ 3,337,710
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Interest Rate 2.41% 2.03%
Repurchase agreements $ 1,388,695 $ 1,480,182
Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Interest Rate 1.60% 1.18%
Repurchase agreements $ 114,759 $ 122,523
Loans Held-for-sale, Residential Mortgages [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Interest Rate 0.00% 2.87%
Repurchase agreements $ 0 $ 8,510
Commercial Real Estate Assets [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Interest Rate 2.93% 2.62%
Repurchase agreements $ 272,381 $ 59,349
Maturity up to 30 days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 3,967,528 2,689,363
Maturity up to 30 days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 3,341,276 1,719,292
Maturity up to 30 days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 588,934 852,436
Maturity up to 30 days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 15,385 58,286
Maturity up to 30 days [Member] | Loans Held-for-sale, Residential Mortgages [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity up to 30 days [Member] | Commercial Real Estate Assets [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 21,933 59,349
Maturity 30 to 59 Days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 2,896,664 1,739,237
Maturity 30 to 59 Days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 2,595,970 1,407,353
Maturity 30 to 59 Days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 207,856 271,819
Maturity 30 to 59 Days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 65,018 60,065
Maturity 30 to 59 Days [Member] | Loans Held-for-sale, Residential Mortgages [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 30 to 59 Days [Member] | Commercial Real Estate Assets [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 27,820 0
Maturity 60 to 89 Days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,185,026 161,449
Maturity 60 to 89 Days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,185,026 143,051
Maturity 60 to 89 Days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 15,691
Maturity 60 to 89 Days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 2,707
Maturity 60 to 89 Days [Member] | Loans Held-for-sale, Residential Mortgages [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 60 to 89 Days [Member] | Commercial Real Estate Assets [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 90 to 119 Days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,012,572 175,486
Maturity 90 to 119 Days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 622,725 68,014
Maturity 90 to 119 Days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 373,474 106,007
Maturity 90 to 119 Days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 16,373 1,465
Maturity 90 to 119 Days [Member] | Loans Held-for-sale, Residential Mortgages [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 90 to 119 Days [Member] | Commercial Real Estate Assets [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity 120 to 364 days [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,352,955 242,739
Maturity 120 to 364 days [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 1,116,541 0
Maturity 120 to 364 days [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 218,431 234,229
Maturity 120 to 364 days [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 17,983 0
Maturity 120 to 364 days [Member] | Loans Held-for-sale, Residential Mortgages [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 8,510
Maturity 120 to 364 days [Member] | Commercial Real Estate Assets [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0 0
Maturity Over One Year [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 222,628 $ 0
Maturity Over One Year [Member] | US Government Agencies Debt Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0  
Maturity Over One Year [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0  
Maturity Over One Year [Member] | Inverse Interest-Only Securities [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0  
Maturity Over One Year [Member] | Loans Held-for-sale, Residential Mortgages [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements 0  
Maturity Over One Year [Member] | Commercial Real Estate Assets [Member]    
Assets Sold under Agreements to Repurchase [Line Items]    
Repurchase agreements $ 222,628