Information Related to Impaired Loans by Segment and Class (Detail) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 389,020	$ 372,457
Recorded Investment	307,901	300,604
Related Allowance	(25,073)	(28,362)
Net Investment	282,828	272,242
One to Four Family | Full Documentation Interest Only Loans | With an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	10,307	11,033
Recorded Investment	10,307	11,033
Related Allowance	(1,238)	(1,980)
Net Investment	9,069	9,053
One to Four Family | Full Documentation Amortizing Loans | With an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	3,966	7,340
Recorded Investment	3,966	7,340
Related Allowance	(467)	(947)
Net Investment	3,499	6,393
One to Four Family | Reduced Documentation Interest Only Loans | With an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	11,508	10,234
Recorded Investment	11,508	10,234
Related Allowance	(1,384)	(2,500)
Net Investment	10,124	7,734
One to Four Family | Reduced Documentation Amortizing Loans | With an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,066	1,032
Recorded Investment	1,066	1,032
Related Allowance	(131)	(239)
Net Investment	935	793
Multi Family | With an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	53,844	51,793
Recorded Investment	53,134	51,084
Related Allowance	(14,278)	(14,349)
Net Investment	38,856	36,735
Commercial Real Estate | With an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	21,604	19,929
Recorded Investment	20,500	18,825
Related Allowance	(4,913)	(5,496)
Net Investment	15,587	13,329
Construction | With an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	5,916	6,546
Recorded Investment	5,806	6,435
Related Allowance	(2,662)	(2,851)
Net Investment	3,144	3,584
One to Four Family | Full Documentation Interest Only Loans | Without an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	92,071	87,110
Recorded Investment	66,285	64,185
Net Investment	66,285	64,185
One to Four Family | Full Documentation Amortizing Loans | Without an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	18,102	15,363
Recorded Investment	13,904	11,883
Net Investment	13,904	11,883
One to Four Family | Reduced Documentation Interest Only Loans | Without an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	150,797	145,091
Recorded Investment	106,652	105,905
Net Investment	106,652	105,905
One to Four Family | Reduced Documentation Amortizing Loans | Without an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	18,639	15,786
Recorded Investment	14,134	12,009
Net Investment	14,134	12,009
Construction | Without an allowance recorded
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,200	1,200
Recorded Investment	639	639
Net Investment	$ 639	$ 639