Investments in Qualified Affordable Housing Projects - Components of Qualified Affordable Housing Projects Included in Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Tax credit amortization	$ 394	$ 472	$ 1,198	$ 995
Tax credits and other benefits	(572)	(671)	(1,717)	(1,519)
Total	$ (178)	$ (199)	$ (519)	$ (524)

Affordable Housing Tax Credits and Other Benefits, Net of Amortization

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114775393&loc=SL49122993-202985

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