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Investment Securities-Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Mar. 31, 2021
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost	$ 410
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost	7,849
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	32,641
Debt Securities, Available-for-sale, Amortized Cost	81,537	$ 89,682
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value	413
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value	7,896
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	31,900
Available-for-sale	$ 79,853	86,507
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Weighted Average Rate	0.75%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Weighted Average Rate	1.91%
Available-for-sale Securities, Debt Maturities, after Ten Years, Weighted Average Rate	1.92%
Available-for-sale Securities, Debt Maturities, Weighted Average Rate	1.60%
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount
Held-to-maturity	$ 5,623	7,807
Held-to-maturity Securities, Debt Maturities, Fair Value, Fiscal Year Maturity
Held-to-maturity, Fair Value	$ 5,865	$ 8,140

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