Derivative Instruments and Hedging Activities Schedule of Inverse Interest-Only Securities Reconciliation (Details) - USD ($) |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
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| Derivatives, Fair Value [Line Items] | ||||||
| Accrued interest receivable | $ 74,156,000 | $ 62,751,000 | ||||
| Face Value | 16,988,116,000 | $ 15,935,535,000 | 18,802,500,000 | $ 26,141,370,000 | $ 26,390,596,000 | $ 21,998,381,000 |
| Derivative Financial Instruments, Assets [Member] | ||||||
| Derivatives, Fair Value [Line Items] | ||||||
| Fair Value | 240,502,000 | 324,182,000 | ||||
| Face Value | 19,023,116,000 | 21,708,907,000 | ||||
| Inverse Interest-Only Securities [Member] | ||||||
| Derivatives, Fair Value [Line Items] | ||||||
| Fair Value | 109,350,000 | 127,843,000 | ||||
| Accrued interest receivable | 1,019,000 | 1,244,000 | ||||
| Face Value | 659,768,052 | 740,844,023 | ||||
| Unamortized premium | 0 | 0 | ||||
| Designated credit reserve | 0 | 0 | ||||
| Net, unamortized | (562,240,000) | (631,082,000) | ||||
| Amortized Cost | 97,528,000 | 109,762,000 | ||||
| Gross unrealized gains | 12,085,000 | 18,389,000 | ||||
| Gross unrealized losses | (1,282,000) | (1,552,000) | ||||
| Market Value | 108,331,000 | 126,599,000 | ||||
| Inverse Interest-Only Securities [Member] | Derivative Financial Instruments, Assets [Member] | ||||||
| Derivatives, Fair Value [Line Items] | ||||||
| Face Value | $ 659,768,052 | $ 740,844,023 |
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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition This item represents the cost of inverse interest-only residential mortgage securities (Agency derivatives), net of adjustments including accretion, amortization, and fair value hedge accounting adjustments, if any. No definition available.
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- Definition Carrying value (excluding accrued interest receivable) as of the balance sheet date of the assets less the liabilities of a derivative or group of derivatives. No definition available.
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- Definition This item represents the amount of unamortized discount on inverse interest-only residential mortgage securities (Agency derivatives) designated as credit reserve on the securities. No definition available.
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- Definition This item represents the gross unrealized gains for inverse interest-only residential mortgage securities (Agency derivatives), at a point in time. No definition available.
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- Definition This item represents the gross unrealized losses for inverse interest-only residential mortgage securities (Agency derivatives), at a point in time. No definition available.
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- Definition This item represents the amount of unamortized discount on inverse interest-only residential mortgage securities (Agency derivatives) not designated as a credit reserve on the securities. No definition available.
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- Definition This item represents the amount of unamortized premium on inverse interest-only residential mortgage securities (Agency derivatives). No definition available.
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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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