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Summary of Significant Accounting Policies (Details Narrative) (USD $) In Thousands, except Share data, unless otherwise specified | 3 Months Ended
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Mar. 31, 2015
Number of Options exercised | 1,703 us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Director's Stock Purchase Plan |
Shares issued | 12 us-gaap_StockIssuedDuringPeriodValueOther / us-gaap_PlanNameAxis = cofs_DirectorsStockPurchasePlanMember
Shares issued (in shares) | 512 us-gaap_StockIssuedDuringPeriodSharesOther / us-gaap_PlanNameAxis = cofs_DirectorsStockPurchasePlanMember

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- Definition Number of shares of stock issued during the period that is attributable to transactions involving issuance of stock not separately disclosed. + References No definition available. + Details
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Period Type: | duration

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- Definition Number of share options (or share units) exercised during the current period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.28,29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 + Details
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- Definition Value of shares of stock issued during the period that is attributable to transactions involving issuance of stock not separately disclosed. + References No definition available. + Details
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- Details
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Period Type: |