Loan Receivable and Allowance for Loan and Lease Losses Impaired Loans with No Specific Allowance Recorded (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2012
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 32,867		$ 39,309
Impaired Financing Receivable, Related Allowance	2,657		949
Impaired Financing Receivable, Average Recorded Investment	27,729	51,569
Impaired Financing Receivable, Interest Income, Cash Basis Method	791	1,519
Impaired Financing Receivable, Recorded Investment	29,678		36,247
Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	14,082		18,213
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Average Recorded Investment	11,868	23,655
Impaired Financing Receivable, Interest Income, Cash Basis Method	328	1,021
Impaired Financing Receivable, Recorded Investment	12,193		17,515
One- to four family loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	1,111		628
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Average Recorded Investment	659	2,176
Impaired Financing Receivable, Interest Income, Cash Basis Method	38	39
Impaired Financing Receivable, Recorded Investment	1,111		628
Multifamily Loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	0		194
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Average Recorded Investment	0	196
Impaired Financing Receivable, Interest Income, Cash Basis Method	5	18
Impaired Financing Receivable, Recorded Investment	0		194
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	9,348		6,304
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Average Recorded Investment	7,402	6,202
Impaired Financing Receivable, Interest Income, Cash Basis Method	191	4
Impaired Financing Receivable, Recorded Investment	8,660		6,304
Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	1,492		5,670
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Average Recorded Investment	2,743	10,139
Impaired Financing Receivable, Interest Income, Cash Basis Method	53	804
Impaired Financing Receivable, Recorded Investment	1,230		5,406
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	2,131		5,417
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Average Recorded Investment	1,064	4,942
Impaired Financing Receivable, Interest Income, Cash Basis Method	41	156
Impaired Financing Receivable, Recorded Investment	1,192		4,983
Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	0		0
Impaired Financing Receivable, Related Allowance	0		0
Impaired Financing Receivable, Average Recorded Investment	0	0
Impaired Financing Receivable, Interest Income, Cash Basis Method	0	0
Impaired Financing Receivable, Recorded Investment	$ 0		$ 0