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
9 Months Ended 12 Months Ended
Sep. 30, 2017
USD ($)
Dec. 31, 2016
USD ($)
Repurchase Agreement Counterparty [Line Items]    
Repurchase agreements $ 18,297,392 $ 9,316,351
Net Counterparty Exposure 2,152,142 1,435,401
Payables due to broker counterparties for unsettled securities purchases 17,900 0
Repurchase Agreement Counterparty, JPMorgan Chase Bank [Member]    
Repurchase Agreement Counterparty [Line Items]    
Repurchase agreements 1,950,484 605,768
Net Counterparty Exposure $ 264,974 $ 174,197
Percent of Equity 6.00% 5.00%
Weighted Average Days to Maturity 219 days 110 days
Repurchase Agreement Counterparty, All Other Counterparties [Member]    
Repurchase Agreement Counterparty [Line Items]    
Repurchase agreements $ 16,346,908 $ 8,710,583
Net Counterparty Exposure $ 1,887,168 $ 1,261,204
Percent of Equity 46.00% 37.00%
Weighted Average Days to Maturity 147 days 75 days
Number of repurchase agreement counterparties with whom amount at risk is less than 10 percent of stockholders' equity 24 22