Loans Receivable and Allowance for Loan Losses - Summary of Loans Receivable by Credit Quality Risk Rating Indicator (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	$ 3,721,099	$ 3,686,862
Total loans	5,259,679	5,196,663
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,165,196	1,174,043
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,404,466	1,400,624
Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	939,018	928,906
Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	212,419	183,289
Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	3,721,099	3,686,862
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	966,444	932,199
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	572,136	577,602
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	52,358	50,951
Special Mention [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	5,429	5,062
Special Mention [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	13,602	15,301
Special Mention [Member] | Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	329	0
Special Mention [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Special Mention [Member] | Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	19,360	20,363
Special Mention [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	31,191	28,551
Special Mention [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,807	2,037
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	123,874	137,362
Substandard [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	21,985	23,011
Substandard [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	52,037	54,592
Substandard [Member] | Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	403	403
Substandard [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	8,449
Substandard [Member] | Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	74,425	86,455
Substandard [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	45,895	46,687
Substandard [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,554	4,220
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	649	649
Doubtful [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Doubtful [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Doubtful [Member] | Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Doubtful [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Doubtful [Member] | Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Doubtful [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	649	649
Doubtful [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Loss [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Loss [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Loss [Member] | Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Loss [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Loss [Member] | Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	0
Loss [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Loss [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total classified and criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	176,881	188,962
Total classified and criticized [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	27,414	28,073
Total classified and criticized [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	65,639	69,893
Total classified and criticized [Member] | Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	732	403
Total classified and criticized [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	0	8,449
Total classified and criticized [Member] | Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	93,785	106,818
Total classified and criticized [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	77,735	75,887
Total classified and criticized [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,361	6,257
Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,082,798	5,007,701
Pass/Watch [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,137,782	1,145,970
Pass/Watch [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,338,827	1,330,731
Pass/Watch [Member] | Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	938,286	928,503
Pass/Watch [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	212,419	174,840
Pass/Watch [Member] | Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	3,627,314	3,580,044
Pass/Watch [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	888,709	856,312
Pass/Watch [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 566,775	$ 571,345