Loan Receivable and Allowance for Loan and Lease Losses Past due financing receivable (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Sep. 30, 2012		Mar. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	$ 4,242		$ 21,030
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	2,753		1,382
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	9,459
Financing Receivable, Recorded Investment, Past Due	16,454		53,876
impaired loans	8,562	[1]	2,081	[1]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	16,932	[2]
Loans Receivable, Net	338,002		335,859
Loans and Leases Receivable, Gross, Carrying Amount	381,756		414,830
Loans and Leases Receivable, Net of Deferred Income	379,950		412,858
One- to four family loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	0		2,381
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	589		0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,170		4,681
Financing Receivable, Recorded Investment, Past Due	3,759		7,062
impaired loans	0	[1]	0	[1]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	2,924	[2]	2,306	[3]
Loans Receivable, Net	55,265		56,804
Loans and Leases Receivable, Gross, Carrying Amount	61,948		66,172
Multifamily Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	0		3,220
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	162		427
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	1,046		1,915
Financing Receivable, Recorded Investment, Past Due	1,208		5,562
impaired loans	0	[1]	0	[1]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	678	[2]	1,008	[3]
Loans Receivable, Net	71,629		72,414
Loans and Leases Receivable, Gross, Carrying Amount	73,515		78,984
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	4,224		11,455
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	1,560		0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	1,778		9,406
Financing Receivable, Recorded Investment, Past Due	7,562		20,861
impaired loans	3,618	[1]	2,000	[1]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	8,749	[2]	13,061	[3]
Loans Receivable, Net	179,712		170,099
Loans and Leases Receivable, Gross, Carrying Amount	199,641		206,022
Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	0		0
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	0		0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0		11,086
Financing Receivable, Recorded Investment, Past Due	0		11,086
impaired loans	4,258	[1]	0	[1]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	0	[2]	239	[3]
Loans Receivable, Net	4,040		5,108
Loans and Leases Receivable, Gross, Carrying Amount	8,298		16,433
Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	0		3,937
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	420		954
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,450		4,353
Financing Receivable, Recorded Investment, Past Due	3,870		9,244
impaired loans	686	[1]	81	[1]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	4,581	[2]	4,428	[3]
Loans Receivable, Net	26,959		30,229
Loans and Leases Receivable, Gross, Carrying Amount	36,096		43,982
Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 30 to 59 Days Past Due	18		37
Financing Receivable, Recorded Investment, 60 to 89 Days Past Due	22		1
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	15		23
Financing Receivable, Recorded Investment, Past Due	55		61
impaired loans	0	[1]	0	[1]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	0	[2]	0	[3]
Loans Receivable, Net	397		1,204
Loans and Leases Receivable, Gross, Carrying Amount	$ 452		$ 1,265

[1] (1) Consists of loans which are less than 90 days past due but impaired due to other risk characteristics.

[2] (2) Excludes $5.2 million TDR loans that have performed in accordance with their modified terms for at least six months and are considered performing. These loans are classified as current.

[3] (2) Excludes $3.5 million TDR loans that have performed in accordance with their modified terms for at least six months and are considered performing. These loans are classified as current.