Loans Receivable and Allowance for Loan Losses - Average Recorded Investment, Interest Income Recognized and Cash Basis Interest Income Related to Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Total impaired loans
Average Recorded Investment	$ 213,019	$ 233,663
Interest Income Recognized	1,922	1,995
Cash Basis Interest Income	1,887	1,993
Consumer and other loans \| Home equity lines of credit
With an allowance recorded:
Average Recorded Investment	3,973	4,753
Interest Income Recognized	13	5
Cash Basis Interest Income	13	9
Mortgage loans \| Residential \| Full documentation interest-only
With an allowance recorded:
Average Recorded Investment	15,144	29,462
Interest Income Recognized	153	189
Cash Basis Interest Income	156	186
Mortgage loans \| Residential \| Full documentation amortizing
With an allowance recorded:
Average Recorded Investment	80,414	64,858
Interest Income Recognized	624	494
Cash Basis Interest Income	614	478
Mortgage loans \| Residential \| Reduced documentation interest-only
With an allowance recorded:
Average Recorded Investment	19,382	43,118
Interest Income Recognized	111	391
Cash Basis Interest Income	103	385
Mortgage loans \| Residential \| Reduced documentation amortizing
With an allowance recorded:
Average Recorded Investment	74,107	57,203
Interest Income Recognized	757	525
Cash Basis Interest Income	738	529
Without an allowance recorded:
Average Recorded Investment	2,645	0
Interest Income Recognized	23	0
Cash Basis Interest Income	21	0
Mortgage loans \| Multi-family
With an allowance recorded:
Average Recorded Investment	1,941	6,813
Interest Income Recognized	26	67
Cash Basis Interest Income	26	79
Without an allowance recorded:
Average Recorded Investment	4,645	13,375
Interest Income Recognized	51	152
Cash Basis Interest Income	55	149
Mortgage loans \| Commercial real estate
With an allowance recorded:
Average Recorded Investment	1,133	3,875
Interest Income Recognized	34	6
Cash Basis Interest Income	30	7
Without an allowance recorded:
Average Recorded Investment	9,598	10,206
Interest Income Recognized	128	166
Cash Basis Interest Income	129	171
Mortgage loans \| Commercial and industrial
Without an allowance recorded:
Average Recorded Investment	37	0
Interest Income Recognized	2	0
Cash Basis Interest Income	$ 2	$ 0

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Impaired Financing Receivable, with No Related Allowance [Abstract]

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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=66008989&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=66008989&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Amount of average investment of impaired financing receivables for which there is no 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 17
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5258-111524

Reference 2: 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=66008989&loc=d3e5212-111524

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