Investment Securities Investment Securities-Investments Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Mar. 31, 2017
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis		$ 7,387
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis		12,142
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis		37,295
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		56,824
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value		7,212
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value		11,859
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value		36,016
Available-for-sale		$ 55,087	$ 59,011
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Weighted Average Rate		1.66%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Weighted Average Rate		2.04%
Available-for-sale Securities, Debt Maturities, after Ten Years, Weighted Average Rate		1.47%
Available-for-sale Securities, Debt Maturities, Weighted Average Rate		1.62%
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount		$ 9,075
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount		3,319
Held-to-maturity	[1]	12,394	13,435
Held-to-maturity Securities, Debt Maturities, Fair Value, Fiscal Year Maturity
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value		9,099
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value		3,317
Held-to-maturity, Fair Value	[1]	$ 12,416	$ 13,497
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Weighted Average Rate		2.81%
Held-to-maturity Securities, Debt Maturities, after Ten Years, Weighted Average Rate		2.64%
Held-to-maturity Securities, Debt Maturities, Weighted Average Rate		2.77%

[1] * The carrying amount and amortized cost are the same for all held-to-maturity securities, as no OTTI has been recorded.