Loans Receivable and Allowance for Loan Losses (Details 6) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average Recorded Investment	$ 342,760	$ 309,898	$ 270,600
Interest Income Recognized	9,781	8,910	8,600
Cash Basis Interest Income	10,212	9,257	9,400
Residential \| Full Documentation Interest-only Loans
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average Recorded Investment, Loans with an allowance recorded	10,436	10,688
Average Recorded Investment, Loans without an allowance recorded	82,631	68,320
Interest Income Recognized, Loans with an allowance recorded	348	420
Interest Income Recognized, Loans without an allowance recorded	1,633	1,402
Cash Basis Interest Income, Loans with an allowance recorded	350	425
Cash Basis Interest Income, Loans without an allowance recorded	1,739	1,626
Residential \| Full Documentation Amortizing Loans
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average Recorded Investment, Loans with an allowance recorded	4,482	5,428
Average Recorded Investment, Loans without an allowance recorded	17,554	13,858
Interest Income Recognized, Loans with an allowance recorded	193	158
Interest Income Recognized, Loans without an allowance recorded	299	214
Cash Basis Interest Income, Loans with an allowance recorded	200	156
Cash Basis Interest Income, Loans without an allowance recorded	332	252
Residential \| Reduced Documentation Interest-only Loans
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average Recorded Investment, Loans with an allowance recorded	11,352	11,239
Average Recorded Investment, Loans without an allowance recorded	115,593	108,857
Interest Income Recognized, Loans with an allowance recorded	542	544
Interest Income Recognized, Loans without an allowance recorded	2,555	2,131
Cash Basis Interest Income, Loans with an allowance recorded	543	539
Cash Basis Interest Income, Loans without an allowance recorded	2,655	2,317
Residential \| Reduced Documentation Amortizing Loans
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average Recorded Investment, Loans with an allowance recorded	2,445	1,248
Average Recorded Investment, Loans without an allowance recorded	17,319	14,130
Interest Income Recognized, Loans with an allowance recorded	114	88
Interest Income Recognized, Loans without an allowance recorded	367	333
Cash Basis Interest Income, Loans with an allowance recorded	119	86
Cash Basis Interest Income, Loans without an allowance recorded	384	341
Multi-Family
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average Recorded Investment, Loans with an allowance recorded	48,196	55,284
Average Recorded Investment, Loans without an allowance recorded	14,617	882
Interest Income Recognized, Loans with an allowance recorded	663	2,168
Interest Income Recognized, Loans without an allowance recorded	2,053	215
Cash Basis Interest Income, Loans with an allowance recorded	715	2,096
Cash Basis Interest Income, Loans without an allowance recorded	2,088	215
Commercial Real Estate
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average Recorded Investment, Loans with an allowance recorded	12,724	19,964
Average Recorded Investment, Loans without an allowance recorded	5,411
Interest Income Recognized, Loans with an allowance recorded	495	1,237
Interest Income Recognized, Loans without an allowance recorded	519
Cash Basis Interest Income, Loans with an allowance recorded	540	1,204
Cash Basis Interest Income, Loans without an allowance recorded	$ 547

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5258-111524

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