MBS, CRT Securities and MSR Related Assets (Composition of OTTI Charges) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Total OTTI losses	$ 0	$ 0	$ 0	$ (63)
OTTI reclassified from OCI	0	0	0	(969)
OTTI recognized in earnings	$ 0	$ 0	$ 0	$ (1,032)

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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Amount of other-than-temporary impairment (OTTI) on investment in debt security, recognized in earnings.

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Amount before tax of other than temporary impairment loss (OTTI) on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss and attributable to parent entity.

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