Investment Securities Investment Securities Carrying Value (Amortized Cost) and Fair Value by remaining period of contractual maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis		$ 5,070
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value		$ 4,962
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Weighted Average Rate		1.65%
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis		$ 14,574
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value		$ 14,104
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Weighted Average Rate		1.99%
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis		$ 42,481
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value		$ 40,958
Available-for-sale Securities, Debt Maturities, after Ten Years, Weighted Average Rate		1.43%
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis		$ 62,125
Available-for-sale		$ 60,024	$ 56,180
Available-for-sale Securities, Debt Maturities, Weighted Average Rate		1.58%
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount		$ 6,654
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value		$ 6,652
Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Weighted Average Rate		3.05%
Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount		$ 7,259
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value		$ 7,255
Held-to-maturity Securities, Debt Maturities, after Ten Years, Weighted Average Rate		2.20%
Held-to-maturity, Amortized Cost	[1]	$ 13,913	15,311
Held-to-maturity Securities, Fair Value	[1]	$ 13,907	$ 15,653
Held-to-maturity Securities, Debt Maturities, Weighted Average Rate		2.61%

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