Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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The cash inflow from the maturity (principal due), prepayment and call (request of early payment) of a loan financed by home mortgage payments classified as held to maturity.

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Amount of cash inflow from sale of investment in mortgage-backed security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Mortgage-Backed Securities - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Sale of securities	$ 539,588	$ 1,335,932	$ 1,709,950	$ 2,239,754
Unrealized gain in other comprehensive income					$ 30,000
Agency MBS
Schedule Of Available For Sale Securities [Line Items]
Sale of securities	400,000	1,340,000	1,400,000	2,240,000
Gross realized losses on sales of securities		4,300		20,500
Gross realized gains on sales of securities	$ 10,100	5,000	19,800	7,700
Unrealized gain (loss) on trading investments		989	$ (1,141)	15,895
Non-Agency MBS
Schedule Of Available For Sale Securities [Line Items]
Sale of securities		$ 0
Securities called				20,000
Gross realized gains on sales of securities				$ 22