Loans Receivable and Allowance for Loan Losses (Details 9) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Average recorded investment, interest income recognized and cash basis interest income related to impaired mortgage loans by segment and class
Average recorded investment	$ 330,190	$ 396,575	$ 342,760
Interest income recognized	10,714	12,216	9,781
Cash basis interest income	10,922	12,677	10,212
Residential mortgage loans \| 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	84,264	106,720	10,436
Average recorded investment, loans without an allowance recorded		11,547	82,631
Interest income recognized, loans with an allowance recorded	1,860	2,938	348
Interest income recognized, loans without an allowance recorded			1,633
Cash basis interest income, loans with an allowance recorded	1,920	3,068	350
Cash basis interest income, loans without an allowance recorded			1,739
Residential mortgage loans \| 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	38,340	30,790	4,482
Average recorded investment, loans without an allowance recorded	365	3,517	17,554
Interest income recognized, loans with an allowance recorded	1,491	948	193
Interest income recognized, loans without an allowance recorded	0		299
Cash basis interest income, loans with an allowance recorded	1,498	974	200
Cash basis interest income, loans without an allowance recorded			332
Residential mortgage loans \| 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	112,172	145,490	11,352
Average recorded investment, loans without an allowance recorded		1,669	115,593
Interest income recognized, loans with an allowance recorded	3,646	4,179	542
Interest income recognized, loans without an allowance recorded			2,555
Cash basis interest income, loans with an allowance recorded	3,671	4,371	543
Cash basis interest income, loans without an allowance recorded			2,655
Residential mortgage loans \| 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	22,137	25,460	2,445
Average recorded investment, loans without an allowance recorded			17,319
Interest income recognized, loans with an allowance recorded	655	696	114
Interest income recognized, loans without an allowance recorded			367
Cash basis interest income, loans with an allowance recorded	653	729	119
Cash basis interest income, loans without an allowance recorded			384
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	30,291	19,130	48,196
Average recorded investment, loans without an allowance recorded	17,225	33,193	14,617
Interest income recognized, loans with an allowance recorded	1,320	737	663
Interest income recognized, loans without an allowance recorded	632	1,606	2,053
Cash basis interest income, loans with an allowance recorded	1,339	789	715
Cash basis interest income, loans without an allowance recorded	633	1,671	2,088
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	17,341	8,112	12,724
Average recorded investment, loans without an allowance recorded	2,853	10,947	5,411
Interest income recognized, loans with an allowance recorded	1,065	367	495
Interest income recognized, loans without an allowance recorded		745	519
Cash basis interest income, loans with an allowance recorded	1,154	377	540
Cash basis interest income, loans without an allowance recorded		698	547
Consumer portfolio segment \| Home equity and other consumer
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	5,202
Interest income recognized, loans with an allowance recorded	45
Cash basis interest income, loans with an allowance recorded	$ 54

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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=35738203&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=35738203&loc=d3e5258-111524

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