Loans Receivable And Allowance For Loan Losses (Summary Of Loans Receivable By Credit Quality Risk Rating Indicator) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	$ 3,303,074	$ 3,241,141
Total loans	4,733,622	4,651,120
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	52,016	75,051
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	212,416	232,317
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	694
Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans
Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	265,126	307,368
Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,468,496	4,343,752
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,307,578	1,308,635
Residential [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	4,503	7,980
Residential [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	34,207	40,386
Residential [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Residential [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Residential [Member] | Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	38,710	48,366
Residential [Member] | Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,268,868	1,260,269
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,277,342	1,253,542
Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	13,740	27,773
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	86,335	82,428
Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Commercial [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Commercial [Member] | Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	100,075	110,201
Commercial [Member] | Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	1,177,267	1,143,341
Multi-Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	598,476	564,147
Multi-Family [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	8,356	12,193
Multi-Family [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	9,068	8,534
Multi-Family [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Multi-Family [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Multi-Family [Member] | Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	17,424	20,727
Multi-Family [Member] | Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	581,052	543,420
Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	119,678	114,817
Construction [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	7,929	10,699
Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	17,388	18,643
Construction [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Construction [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Construction [Member] | Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	25,317	29,342
Construction [Member] | Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	94,361	85,475
Mortgage Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	3,303,074	3,241,141
Mortgage Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	34,528	58,645
Mortgage Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	146,998	149,991
Mortgage Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Mortgage Loans [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans
Mortgage Loans [Member] | Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	181,526	208,636
Mortgage Loans [Member] | Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total mortgage loans	3,121,548	3,032,505
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	854,257	849,009
Commercial Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	15,407	14,498
Commercial Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	58,509	73,793
Commercial Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	694
Commercial Loans [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans
Commercial Loans [Member] | Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	74,610	88,291
Commercial Loans [Member] | Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	779,647	760,718
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	576,291	560,970
Consumer Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,081	1,908
Consumer Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,909	8,533
Consumer Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans
Consumer Loans [Member] | Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans
Consumer Loans [Member] | Total Classified And Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,990	10,441
Consumer Loans [Member] | Pass/Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 567,301	$ 550,529