Qualified Affordable Housing Projects and Other Tax Credit Investments - Schedule of Qualified Affordable Housing Projects and Other Tax Credit Investments (Detail) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015
Investment Holdings [Line Items]
Total	$ 29,848
Total	15,429
Amortization Expense	603	$ 710
Tax Benefit Recognized	(843)	(1,018)
LIHTC and Other Qualifying Investments [Member]
Investment Holdings [Line Items]
Proportional amortization method of investment	23,910
Unfunded commitment, Proportional amortization	10,823
Amortization Expense	603	603
Tax Benefit Recognized	(843)	(843)
FHTC [Member]
Investment Holdings [Line Items]
Equity method investment	4,434
Unfunded commitment, Equity	3,104
CReED [Member]
Investment Holdings [Line Items]
Equity method investment	1,504
Unfunded commitment, Equity	$ 1,502
NMTC [Member]
Investment Holdings [Line Items]
Amortization Expense		107
Tax Benefit Recognized		$ (175)

Amortization method qualified affordable housing project investments commitment.

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Equity method investment qualified affordable housing project investments.

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Equity method qualified affordable housing project investments commitment.

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Investments in qualified affordable housing projects.

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Amount of affordable housing tax credits and other tax benefits recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=64813897&loc=SL49122993-202985

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Amount of investment in qualified affordable housing projects.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64813897&loc=SL49122993-202985

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Amount of amortization expense of investment in qualified affordable housing projects.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
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-Section 50
-Paragraph 2
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Amount of commitment or contingent commitments to qualified affordable housing project investments.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
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