Investment Securities Carrying Value (Amortized Cost) and Fair Value by remaining period of contractual maturity (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
AFS Amortized Cost One through five years	$ 2,000
AFS Amortized Cost Five through ten years	32,044
AFS Amortized Cost After ten years	85,684
AFS Amortized Cost Total	119,728
AFS Fair Value One through five years	1,969
AFS Fair Value Five through ten years	31,052
AFS Fair Value After ten years	83,356
AFS Fair Value	116,377	116,051
AFS Weighted Average Rate One through five years	1.50%
AFS Weighted Average Rate Five through ten years	1.52%
Available-for-sale Securities, Debt Maturities, after Ten Years, Weighted Average Rate	1.54%
AFS Weighted Average Rate Total	1.54%
Held-to-Maturity Security Amortized Cost One through Five years	135
HTM Amortized Cost Five through ten years	5,201
HTM Amortized Cost After ten years	8,201
HTM Amortized Cost Total	13,537
Held-to-maturity securities, one through five years, fair value	138
HTM Fair Value Five through ten years	4,904
HTM Fair Value After ten years	8,626
HTM Fair Value Total	$ 13,668
Held-to-maturity Securities, Debt Maturities, One Through Five Years, Weighted Average Rate	2.76%
HTM Weighted Average Rate Five through ten years	2.42%
HTM Weighted Average Rate After ten years	3.52%
HTM Weighted Average Rate Total	3.09%