Allowance for Loan Losses - Loans by Credit Quality Indicators - Performing and Non-Performing (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Allowance for loan losses
Loans	$ 1,027,788	$ 999,740
Consumer Finance
Allowance for loan losses
Loans	292,004	304,357
Consumer Finance \| Performing
Allowance for loan losses
Loans	291,240	303,142
Consumer Finance \| Nonperforming
Allowance for loan losses
Loans	764	$ 1,215
CVBK \| Pass
Allowance for loan losses
Loans	42,670
CVBK \| Special Mention
Allowance for loan losses
Loans	1,090
CVBK \| Substandard
Allowance for loan losses
Loans	1,980
CVBK \| Substandard Nonaccrual
Allowance for loan losses
Loans	$ 161

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant