Investment In Securities - Unrealized Gain or Loss Position and Components of Carrying Value of Available for Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Principal Amount	$ 1,248,910	$ 1,738,906
Total Available for Sale Securities	1,280,872	1,791,871
Gross Unrealized Loss	(45)	(44)
Gross Unrealized Gain	107,018	179,075
Fair Value	1,387,845	1,970,902
Fannie Mae
Debt Securities, Available-for-sale [Line Items]
Principal Amount	1,063,403	1,359,136
Total Available for Sale Securities	1,088,209	1,397,206
Gross Unrealized Loss	(21)	(1)
Gross Unrealized Gain	99,138	159,603
Fair Value	1,187,326	1,556,808
Freddie Mac
Debt Securities, Available-for-sale [Line Items]
Principal Amount	172,550	354,382
Total Available for Sale Securities	179,385	368,686
Gross Unrealized Loss	(4)	0
Gross Unrealized Gain	7,797	19,246
Fair Value	187,178	387,932
Ginnie Mae
Debt Securities, Available-for-sale [Line Items]
Principal Amount	12,957	25,388
Total Available for Sale Securities	13,278	25,979
Gross Unrealized Loss	(20)	(43)
Gross Unrealized Gain	83	226
Fair Value	$ 13,341	$ 26,162

Debt Securities, Available-for-sale, Principal Amount

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) 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, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) 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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Amortized cost of 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 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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