Loans Receivable and Allowance for Loan Losses - Summary of Aging Loans Receivable by Portfolio Segment and Class (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	$ 12,798	$ 14,105
60-89 Days	6,051	7,651
Non-accrual	65,363	76,680
Total Past Due and Non-accrual	84,212	98,436
Current	5,823,475	5,098,227
Total loans	5,907,687	5,196,663
Recorded Investment > 90 days accruing	0	0
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	385	305
60-89 Days	1	77
Non-accrual	20,914	22,228
Total Past Due and Non-accrual	21,300	22,610
Current	1,180,441	909,589
Total loans	1,201,741	932,199
Recorded Investment > 90 days accruing	0	0
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	2,084	2,474
60-89 Days	1,478	2,194
Non-accrual	3,284	3,928
Total Past Due and Non-accrual	6,846	8,596
Current	610,666	569,006
Total loans	617,512	577,602
Recorded Investment > 90 days accruing	0	0
Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days	10,329	11,326
60-89 Days	4,572	5,380
Non-accrual	41,165	50,524
Total Past Due and Non-accrual	56,066	67,230
Current	4,032,368	3,619,632
Total loans	4,088,434	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	10,329	10,639
60-89 Days	4,572	5,062
Non-accrual	21,323	23,011
Total Past Due and Non-accrual	36,224	38,712
Current	1,186,921	1,135,331
Total loans	1,223,145	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	0	687
60-89 Days	0	318
Non-accrual	19,439	18,662
Total Past Due and Non-accrual	19,439	19,667
Current	1,650,175	1,380,957
Total loans	1,669,614	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	967,839	928,503
Total loans	968,242	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	227,433	174,841
Total loans	227,433	183,289
Recorded Investment > 90 days accruing	0	0
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 1,201,741	$ 932,199