Investment Securities Unrealized losses and fair value of securities (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Sep. 30, 2013	Mar. 31, 2013
Gain (Loss) on Investments [Line Items]
Unrealized Loss on Securities	$ (5,153)	$ (290)
Total securities Estimated Fair Value	99,764	125,680
Total mortgage-backed securities AFS
Gain (Loss) on Investments [Line Items]
AFS unrealized losses less than 12 months	(1,066)	(104)
AFS Fair Value less than 12 months	29,132	10,298
AFS unrealized losses 12 months of longer	0	0
AFS Fair Value 12 months or longer	0	0
AFS total unrealized losses	(1,066)	(104)
Total Fair Value AFS	29,132	10,298
Held-to-maturity Securities, unrealized losses, less than 12 months	(277)
Held-to-maturity Securities fair value, Less than Twelve Months	4,851
Held-to-maturity Securities, Unrealized Losses, 12 Months or Longer	0
Held-to-maturity Securities, fair value, Twelve Months or Longer	0
Held-to-maturity Securities,total unrealized Losses	(277)
Total fair value Held-to-maturity Securities	4,851
US Government Agency Securities
Gain (Loss) on Investments [Line Items]
AFS unrealized losses less than 12 months	(3,291)	(177)
AFS Fair Value less than 12 months	45,200	25,290
AFS unrealized losses 12 months of longer	(140)	0
AFS Fair Value 12 months or longer	1,859	0
AFS total unrealized losses	(3,431)	(177)
Total Fair Value AFS	47,059	25,290
Other
Gain (Loss) on Investments [Line Items]
AFS unrealized losses less than 12 months	(379)	(9)
AFS Fair Value less than 12 months	9,621	9,991
AFS unrealized losses 12 months of longer	0	0
AFS Fair Value 12 months or longer	0	0
AFS total unrealized losses	(379)	(9)
Total Fair Value AFS	9,621	9,991
Total available-for-sale securities [Member]
Gain (Loss) on Investments [Line Items]
AFS unrealized losses less than 12 months	(4,736)	(290)
AFS Fair Value less than 12 months	83,953	45,579
AFS unrealized losses 12 months of longer	(140)	0
AFS Fair Value 12 months or longer	1,859	0
AFS total unrealized losses	(4,876)	(290)
Total Fair Value AFS	85,812	45,579
Total held-to-maturity Securities [Member]
Gain (Loss) on Investments [Line Items]
Held-to-maturity Securities, unrealized losses, less than 12 months	(277)
Held-to-maturity Securities fair value, Less than Twelve Months	4,851
Held-to-maturity Securities, Unrealized Losses, 12 Months or Longer	0
Held-to-maturity Securities, fair value, Twelve Months or Longer	0
Held-to-maturity Securities,total unrealized Losses	(277)
Total fair value Held-to-maturity Securities	4,851
Total securities [Member]
Gain (Loss) on Investments [Line Items]
Total Securities unrealized Loss Position Less than 12 months	(5,013)
Total Securities Unrealized Loss Position Less than 12 months Fair Value	88,804
Total Securities, Unrealized Loss Position ,12 months or Longer	(140)
Total Securities, Unrealized Loss Position, 12 months or Longer, Fair Value	1,859
Unrealized Loss on Securities	(5,153)
Total securities Estimated Fair Value	$ 90,663