Loans Receivable and Allowance for Loan Losses - Summary of Aging Loans Receivable by Portfolio Segment and Class (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	$ 16,223	$ 14,105
60-89 Days	7,279	7,651
Non-accrual	64,056	76,680
Total Past Due and Non-accrual	87,558	98,436
Current	5,172,121	5,098,227
Total loans	5,259,679	5,196,663
Recorded Investment > 90 days accruing	0	0
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	4,322	305
60-89 Days	42	77
Non-accrual	19,350	22,228
Total Past Due and Non-accrual	23,714	22,610
Current	942,730	909,589
Total loans	966,444	932,199
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	2,756	2,474
60-89 Days	1,808	2,194
Non-accrual	3,400	3,928
Total Past Due and Non-accrual	7,964	8,596
Current	564,172	569,006
Total loans	572,136	577,602
Recorded Investment > 90 days accruing	0	0
Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	9,145	11,326
60-89 Days	5,429	5,380
Non-accrual	41,306	50,524
Total Past Due and Non-accrual	55,880	67,230
Current	3,665,219	3,619,632
Total loans	3,721,099	3,686,862
Recorded Investment > 90 days accruing	0	0
Mortgage Loans [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	7,742	10,639
60-89 Days	5,429	5,062
Non-accrual	21,985	23,011
Total Past Due and Non-accrual	35,156	38,712
Current	1,130,040	1,135,331
Total loans	1,165,196	1,174,043
Recorded Investment > 90 days accruing	0	0
Mortgage Loans [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	1,403	687
60-89 Days	0	318
Non-accrual	18,918	18,662
Total Past Due and Non-accrual	20,321	19,667
Current	1,384,145	1,380,957
Total loans	1,404,466	1,400,624
Recorded Investment > 90 days accruing	0	0
Mortgage Loans [Member] | Multi-Family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
Non-accrual	403	403
Total Past Due and Non-accrual	403	403
Current	938,615	928,503
Total loans	939,018	928,906
Recorded Investment > 90 days accruing	0	0
Mortgage Loans [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	0	0
60-89 Days	0	0
Non-accrual	0	8,448
Total Past Due and Non-accrual	0	8,448
Current	212,419	174,841
Total loans	212,419	183,289
Recorded Investment > 90 days accruing	0	0
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	966,444	932,199
Recorded Investment > 90 days accruing		$ 0