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Schedule of Derivative Activity (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Dec. 31, 2017
Interest Rate Swap [Member] |  |
Derivative [Line Items] |  |
Financial derivative average monthly notional | $ 630,497 | $ 549,907
TBA securities [Member] |  |
Derivative [Line Items] |  |
Financial derivative average monthly notional | 707,333 | 796,813
Futures [Member] |  |
Derivative [Line Items] |  |
Financial derivative average monthly notional | 172,575 | 30,092
Swaption [Member] |  |
Derivative [Line Items] |  |
Financial derivative average monthly notional | $ 10,000 | $ 4,615

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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. + References No definition available. + Details
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