Qualified Affordable Housing Projects (Details)	3 Months Ended
Mar. 31, 2018 USD ($) commitment	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) commitment
Other Commitments [Line Items]
Qualified Affordable Housing Project Investments, Commitment			$ 0
Investment in qualified affordable housing projects	$ 8,000,000		8,700,000
Amortization expense included in noninterest expense	700,000	$ 800,000
Tax credits	800,000	$ 900,000
Federal Historic Tax Credit Project
Other Commitments [Line Items]
Investment in qualified affordable housing projects	$ 800,000		$ 800,000
Number of open commitments to fund future investments \| commitment	1		1

Qualified Affordable Housing Project Investments, Commitment, Number

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- Definition

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

+ Details

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Amount of investment in qualified affordable housing projects.

+ 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 (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.

+ 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 (c)
-URI http://asc.fasb.org/extlink&oid=64813897&loc=SL49122993-202985

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+ References

No definition available.

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- Definition

Amount of commitment or contingent commitments to qualified affordable housing project investments.

+ 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 (e)
-URI http://asc.fasb.org/extlink&oid=64813897&loc=SL49122993-202985

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