Investment Securities Unrealized losses and fair value of securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	$ (57)	$ (2,437)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	12,943	51,174
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(1,090)	(2,335)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	58,499	38,238
Available-for-sale Securities, Gross Unrealized Loss	(1,147)	(4,772)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	71,442	89,412
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss		(283)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		4,796
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss		(283)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value		4,796
Securities Continuous Loss Position Less than 12 months	(57)	(2,720)
Securities Continuous Unrealized Loss Position Less than 12 months Fair Value	12,943	55,970
Securities, Continuous Unrealized Loss Position ,12 months or Longer	(1,090)	(2,335)
Securities, Continuous Unrealized Loss Position, 12 months or Longer, Fair Value	58,499	38,238
Unrealized Loss on Securities	(1,147)	(5,055)
Securities, Continuous Unrealized Loss Position, Fair Value	71,442	94,208
Mortgage-backed securities
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	0	(322)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	7,569
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(287)	(1,015)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	22,297	20,123
Available-for-sale Securities, Gross Unrealized Loss	(287)	(1,337)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	22,297	27,692
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss		(283)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		4,796
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss		(283)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value		4,796
US Government Agency Securities
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(57)	(1,646)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	12,943	34,074
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(605)	(1,320)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	26,400	18,115
Available-for-sale Securities, Gross Unrealized Loss	(662)	(2,966)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	39,343	52,189
Other
Schedule of Investments [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	0	(469)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	9,531
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(198)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	9,802	0
Available-for-sale Securities, Gross Unrealized Loss	(198)	(469)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 9,802	$ 9,531