Fair Value Measurements-Assets Measured on Recurring basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	$ 0	$ 0
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	0	0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	147	145
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	147	145
Investments, Fair Value Disclosure	86,507	65,829
Assets, Fair Value Disclosure	86,654	65,974
Fair Value, Measurements, Recurring | Government National Mortgage Association (GNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	1,026	3,587
Fair Value, Measurements, Recurring | Federal Home Loan Mortgage Corporation (FHLMC)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	27,785	9,538
Fair Value, Measurements, Recurring | Federal National Mortgage Association (FNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	14,610	22,168
Fair Value, Measurements, Recurring | US Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	18,631	26,481
Fair Value, Measurements, Recurring | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	4,481	4,055
Fair Value, Measurements, Recurring | Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	16,610
Fair Value, Measurements, Recurring | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	3,364
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	0	0
Investments, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Government National Mortgage Association (GNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Federal Home Loan Mortgage Corporation (FHLMC)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Federal National Mortgage Association (FNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | US Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights	0	0
Investments, Fair Value Disclosure	86,507	65,829
Assets, Fair Value Disclosure	86,507	65,829
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Government National Mortgage Association (GNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	1,026	3,587
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Federal Home Loan Mortgage Corporation (FHLMC)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	27,785	9,538
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Federal National Mortgage Association (FNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	14,610	22,168
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | US Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	18,631	26,481
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	4,481	4,055
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	16,610
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	3,364
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	147	145
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Government National Mortgage Association (GNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Federal Home Loan Mortgage Corporation (FHLMC)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Federal National Mortgage Association (FNMA)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | US Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0	$ 0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	$ 0