FANNIE MAE COMMITMENTS AND PLEDGED SECURITIES - Agency Multifamily Mortgage Based Securities Pledged Securities (Detail) - Agency Mortgage Backed Securities - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Investments in Agency debt securities
Fair Value	$ 104,263	$ 119,763
Amortized Cost	100,847	117,136
Total gains for securities with net gains in AOCI	3,636	2,669
Total losses for securities with net losses in AOCI	(220)	(42)
Fair value of securities with unrealized losses	4,757	12,267
Maturities - Fair Value
After one year through five years	2,416
After five years through ten years	73,025
After ten years	28,822
Total	104,263	119,763
Maturities - Amortized Cost
After one year through five years	2,412
After five years through ten years	72,224
After ten years	26,211
Total	$ 100,847	$ 117,136