INVESTMENT SECURITIES - Held to maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023
INVESTMENT SECURITIES
Amortized Cost	$ 236,018	$ 243,843
Gross Unrealized Losses	(42,735)	(33,629)
Estimated Fair Value	193,283	210,214
Municipal securities
INVESTMENT SECURITIES
Amortized Cost	10,332	10,344
Gross Unrealized Losses	(3,516)	(2,859)
Estimated Fair Value	6,816	7,485
Agency securities
INVESTMENT SECURITIES
Amortized Cost	54,031	53,941
Gross Unrealized Losses	(6,080)	(5,091)
Estimated Fair Value	47,951	48,850
Real estate mortgage investment conduits
INVESTMENT SECURITIES
Amortized Cost	33,366	35,186
Gross Unrealized Losses	(6,236)	(4,769)
Estimated Fair Value	27,130	30,417
Residential mortgage-backed securities
INVESTMENT SECURITIES
Amortized Cost	117,761	123,773
Gross Unrealized Losses	(22,826)	(17,542)
Estimated Fair Value	94,935	106,231
Other mortgage-backed securities
INVESTMENT SECURITIES
Amortized Cost	20,528	20,599
Gross Unrealized Losses	(4,077)	(3,368)
Estimated Fair Value	$ 16,451	$ 17,231