Investment Securities Unrealized losses and fair value of securities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Mar. 31, 2012
Asset-backed Securities [Member]
Gain (Loss) on Investments [Line Items]
Total Fair Value AFS	$ 6,716
AFS Amortized Cost	15,237
AFS unrealized losses less than 12 months	(21)
AFS Fair Value less than 12 months	6,716
AFS unrealized losses 12 months of longer	0
AFS Fair Value 12 months or longer	0
AFS Gross Unrealized Losses	(21)
Total mortgage-backed securities AFS
Gain (Loss) on Investments [Line Items]
Total Fair Value AFS	21,109	13,699
AFS Amortized Cost	39,934	45,782
AFS unrealized losses less than 12 months	(188)	(25)
AFS Fair Value less than 12 months	17,123	13,699
AFS unrealized losses 12 months of longer	(53)	0
AFS Fair Value 12 months or longer	3,986	0
AFS Gross Unrealized Losses	(241)	(25)
US Government Agency Securities
Gain (Loss) on Investments [Line Items]
Total Fair Value AFS	11,044	9,917
AFS Amortized Cost	43,128	23,176
AFS unrealized losses less than 12 months	(20)	(63)
AFS Fair Value less than 12 months	11,044	9,917
AFS unrealized losses 12 months of longer	0	0
AFS Fair Value 12 months or longer	0	0
AFS Gross Unrealized Losses	(20)	(63)
Treasuries
Gain (Loss) on Investments [Line Items]
Total Fair Value AFS	1,552	1,555
AFS unrealized losses less than 12 months	0	(1)
AFS Fair Value less than 12 months	1,552	1,555
AFS unrealized losses 12 months of longer	0	0
AFS Fair Value 12 months or longer	0	0
AFS Gross Unrealized Losses	0	(1)
Other
Gain (Loss) on Investments [Line Items]
Total Fair Value AFS		9,973
AFS Amortized Cost	10,485	10,536
AFS unrealized losses less than 12 months		(27)
AFS Fair Value less than 12 months		9,973
AFS unrealized losses 12 months of longer		0
AFS Fair Value 12 months or longer		0
AFS Gross Unrealized Losses	0	(27)
Debt Securities [Member]
Gain (Loss) on Investments [Line Items]
Total Fair Value AFS	40,421	35,144
AFS unrealized losses less than 12 months	(229)	(116)
AFS Fair Value less than 12 months	36,435	35,144
AFS unrealized losses 12 months of longer	(53)	0
AFS Fair Value 12 months or longer	3,986	0
AFS Gross Unrealized Losses	$ (282)	$ (116)