FANNIE MAE COMMITMENTS AND PLEDGED SECURITIES - Agency Multifamily Mortgage Based Securities Pledged Securities (Detail) - Agency MBS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Investments in Agency debt securities
Fair Value	$ 156,891	$ 142,798
Amortized Cost	155,504	143,862
Total gains for securities with net gains in AOCI	2,557	1,036
Total losses for securities with net losses in AOCI	(1,170)	(2,100)
Fair value of securities with unrealized losses	97,834	103,003
Maturities - Fair Value
Within one year	228
After one year through five years	70,035
After five years through ten years	69,219
After ten years	17,409
Total	156,891	142,798
Maturities - Amortized Cost
Within one year	228
After one year through five years	69,994
After five years through ten years	68,332
After ten years	16,950
Total	$ 155,504	$ 143,862