Quarterly report pursuant to Section 13 or 15(d)

Schedule of Repurchase Agreement Counterparties with Whom Repurchase Agreements Exceed 10 Percent of Stockholders' Equity (Details)

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Schedule of Repurchase Agreement Counterparties with Whom Repurchase Agreements Exceed 10 Percent of Stockholders' Equity (Details)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Repurchase Agreement Counterparty [Line Items]    
Repurchase agreements $ 19,148,679 $ 19,451,207
Net Counterparty Exposure 1,741,489 1,743,123
Repurchase Agreement Counterparty, Barclays Capital [Member]    
Repurchase Agreement Counterparty [Line Items]    
Repurchase agreements 2,296,533 1,958,741
Net Counterparty Exposure $ 268,001 $ 275,128
Percent of Equity 8.00% 8.00%
Weighted Average Days to Maturity 120 days 93 days
Repurchase Agreement Counterparty, All Other Counterparties [Member]    
Repurchase Agreement Counterparty [Line Items]    
Repurchase agreements $ 16,852,146 $ 17,492,466
Net Counterparty Exposure $ 1,473,488 $ 1,467,995
Percent of Equity 42.00% 41.00%
Weighted Average Days to Maturity 94 days 82 days
Number of repurchase agreement counterparties with whom amount at risk is less than 10 percent of stockholders' equity 27 26