RIVERVIEW BANCORP, INC. (PARENT COMPANY ONLY) - SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED):
Interest and dividend income	$ 13,941	$ 14,443	$ 14,088	$ 13,194	$ 12,389	$ 12,551	$ 12,965	$ 11,920	$ 55,666	$ 49,825	$ 48,344
Interest expense	2,127	743	657	533	483	492	589	636	4,060	2,200	3,427
Net interest income	11,814	13,700	13,431	12,661	11,906	12,059	12,376	11,284	51,606	47,625	44,917
Provision for (recapture of) loan losses	750				(650)	(1,275)	(1,100)	(1,600)		(4,625)	6,300
Non-interest income, net	2,971	2,963	3,134	3,126	2,966	3,116	3,074	3,588	12,194	12,744	11,090
Non-interest expense	9,950	9,848	9,804	9,769	10,115	9,279	8,187	9,137	39,371	36,718	36,254
Income before income taxes	4,085	6,815	6,761	6,018	5,407	7,171	8,363	7,335	23,679	28,276	13,453
Provision for income taxes	1,102	1,575	1,567	1,366	1,282	1,661	1,933	1,580	5,610	6,456	2,981
Net income	$ 2,983	$ 5,240	$ 5,194	$ 4,652	$ 4,125	$ 5,510	$ 6,430	$ 5,755	$ 18,069	$ 21,820	$ 10,472
Basic earnings per common share (1)	$ 0.14	$ 0.24	$ 0.24	$ 0.21	$ 0.19	$ 0.25	$ 0.29	$ 0.26	$ 0.84	$ 0.98	$ 0.47
Diluted earnings per common share (1)	$ 0.14	$ 0.24	$ 0.24	$ 0.21	$ 0.19	$ 0.25	$ 0.29	$ 0.26	$ 0.83	$ 0.98	$ 0.47
RIVERVIEW BANCORP, INC. (PARENT COMPANY ONLY)
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED):
Non-interest expense									$ 1,567	$ 813	$ 874
Income before income taxes									(1,438)	(797)	(857)
Provision for income taxes									(303)	(167)	(180)
Net income									$ 18,069	$ 21,820	$ 10,472