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Regulatory Capital Requirements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Bank
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Proceeds from Dividends Received		$ 0
Bank | Line of Credit Interest and Trust Preferred Securities Interest and Preferred Dividends
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Proceeds from Dividends Received	$ 2,800,000
Federal Deposit Corporation And Federal Reserve Board | Rules Phased in beginning January 2016
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Additional capital conservation buffer requirement subsequent years ratio	2.50%
New capital conservation buffer requirement beginning ratio	0.625%
Capital conservation buffer requirement ratio	1.25%

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The additional capital conservation buffer ratio requirement in subsequent years.

+ References

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The new capital conservation buffer ratio requirement beginning in January 2016.

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- Definition

Dividends received on equity and other investments during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

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