XML 45 R36.htm IDEA: XBRL DOCUMENT
v3.23.3

Loans and Allowance for Credit Losses - Schedule of Information Regarding Credit Exposure (Details) - USD ($) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2023 | Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | $ 71,442 |
2022 | 83,396 |
2021 | 37,408 |
2020 | 20,355 |
2019 | 14,764 |
Prior | 43,723 |
Term Loans Total | 271,088 |
Revolving Loans | 63,105 |
Grand Total | 334,193 |
Loans | 1,309,800 | $ 1,189,782
Total nonaccrual loans | 1,670 | 1,263
Agricultural [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 1,963 |
2022 | 4,129 |
2021 | 3,134 |
2020 | 1,813 |
2019 | 7,360 |
Prior | 18,379 |
Term Loans Total | 36,778 |
Revolving Loans | 6,512 |
Grand Total | 43,290 |
Current year-to-date gross write-offs, 2023 | 0 |
Current year-to-date gross write-offs, 2022 | 0 |
Current year-to-date gross write-offs, 2021 | 0 |
Current year-to-date gross write-offs, 2020 | 0 |
Current year-to-date gross write-offs, 2019 | 0 |
Financing Receivable Originated Writeoffs Five or More Years Before Latest Fiscal Year, Total | 0 |
Current year-to-date gross write-offs, Term Loans Total | 0 |
Current year-to-date gross write-offs, Revolving Loans | 0 |
Current year-to-date gross write-offs, Grand Total | 0 |
Loans | 43,290 | 64,159
Agricultural [Member] | Pass [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 1,963 |
2022 | 4,129 |
2021 | 3,134 |
2020 | 1,813 |
2019 | 7,184 |
Prior | 18,311 |
Term Loans Total | 36,534 |
Revolving Loans | 6,512 |
Grand Total | 43,046 |
Loans |  | 63,867
Agricultural [Member] | Special Mention [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 176 |
Prior | 68 |
Term Loans Total | 244 |
Revolving Loans | 0 |
Grand Total | 244 |
Loans |  | 289
Agricultural [Member] | Substandard [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 3
Agricultural [Member] | Doubtful [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Agricultural [Member] | Loss [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Commercial and Industrial [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 17,445 |
2022 | 47,390 |
2021 | 25,139 |
2020 | 11,623 |
2019 | 11,160 |
Prior | 12,989 |
Term Loans Total | 125,746 |
Revolving Loans | 96,611 |
Grand Total | 222,357 |
Current year-to-date gross write-offs, 2023 | 0 |
Current year-to-date gross write-offs, 2022 | 0 |
Current year-to-date gross write-offs, 2021 | 0 |
Current year-to-date gross write-offs, 2020 | 71 |
Current year-to-date gross write-offs, 2019 | 0 |
Financing Receivable Originated Writeoffs Five or More Years Before Latest Fiscal Year, Total | 0 |
Current year-to-date gross write-offs, Term Loans Total | 71 |
Current year-to-date gross write-offs, Revolving Loans | 0 |
Current year-to-date gross write-offs, Grand Total | 71 |
Loans | 222,357 | 210,210
Total nonaccrual loans | 103 |
Commercial and Industrial [Member] | Pass [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 17,445 |
2022 | 47,330 |
2021 | 25,078 |
2020 | 11,584 |
2019 | 11,077 |
Prior | 12,891 |
Term Loans Total | 125,405 |
Revolving Loans | 96,604 |
Grand Total | 222,009 |
Loans |  | 209,700
Commercial and Industrial [Member] | Special Mention [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 31 |
2020 | 39 |
2019 | 83 |
Prior | 82 |
Term Loans Total | 235 |
Revolving Loans | 7 |
Grand Total | 242 |
Loans |  | 400
Commercial and Industrial [Member] | Substandard [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 1,560 |
Term Loans Total | 1,560 |
Revolving Loans | 0 |
Grand Total | 1,560 |
Loans |  | 110
Commercial and Industrial [Member] | Doubtful [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Commercial and Industrial [Member] | Loss [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Construction Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 777 |
2022 | 1,089 |
2021 | 557 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 2,423 |
Revolving Loans | 14,054 |
Grand Total | 16,477 |
Current year-to-date gross write-offs, 2023 | 0 |
Current year-to-date gross write-offs, 2022 | 0 |
Current year-to-date gross write-offs, 2021 | 0 |
Current year-to-date gross write-offs, 2020 | 0 |
Current year-to-date gross write-offs, 2019 | 0 |
Financing Receivable Originated Writeoffs Five or More Years Before Latest Fiscal Year, Total | 0 |
Current year-to-date gross write-offs, Term Loans Total | 0 |
Current year-to-date gross write-offs, Revolving Loans | 0 |
Current year-to-date gross write-offs, Grand Total | 0 |
Loans | 16,477 | 14,736
Total nonaccrual loans |  | 0
Construction Real Estate [Member] | Performing Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 777 |
2022 | 1,089 |
2021 | 557 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 2,423 |
Revolving Loans | 14,054 |
Grand Total | 16,477 |
Loans |  | 14,736
Construction Real Estate [Member] | Nonperforming Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Construction Real Estate [Member] | Nonaccrual Financing Receivable [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Consumer Portfolio Segment [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 8,246 |
2022 | 14,922 |
2021 | 7,421 |
2020 | 3,332 |
2019 | 1,472 |
Prior | 1,404 |
Term Loans Total | 36,797 |
Revolving Loans | 808 |
Grand Total | 37,605 |
Current year-to-date gross write-offs, 2023 | 1 |
Current year-to-date gross write-offs, 2022 | 13 |
Current year-to-date gross write-offs, 2021 | 11 |
Current year-to-date gross write-offs, 2020 | 28 |
Current year-to-date gross write-offs, 2019 | 0 |
Financing Receivable Originated Writeoffs Five or More Years Before Latest Fiscal Year, Total | 1 |
Current year-to-date gross write-offs, Term Loans Total | 54 |
Current year-to-date gross write-offs, Revolving Loans | 0 |
Current year-to-date gross write-offs, Grand Total | 54 |
Loans | 37,605 | 39,808
Total nonaccrual loans |  | 0
Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 8,246 |
2022 | 14,922 |
2021 | 7,421 |
2020 | 3,332 |
2019 | 1,472 |
Prior | 1,404 |
Term Loans Total | 36,797 |
Revolving Loans | 808 |
Grand Total | 37,605 |
Loans |  | 39,808
Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Consumer Portfolio Segment [Member] | Nonaccrual Financing Receivable [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Commercial Real Estate Portfolio Segment [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 72,271 |
2022 | 137,771 |
2021 | 109,265 |
2020 | 73,112 |
2019 | 45,074 |
Prior | 143,397 |
Term Loans Total | 580,890 |
Revolving Loans | 129,070 |
Grand Total | 709,960 |
Loans | 709,960 | 630,953
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 72,271 |
2022 | 137,771 |
2021 | 109,265 |
2020 | 73,112 |
2019 | 45,074 |
Prior | 141,265 |
Term Loans Total | 578,758 |
Revolving Loans | 129,070 |
Grand Total | 707,828 |
Loans |  | 624,555
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 572 |
Term Loans Total | 572 |
Revolving Loans | 0 |
Grand Total | 572 |
Loans |  | 2,048
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 60 |
2021 | 30 |
2020 | 0 |
2019 | 0 |
Prior | 16 |
Term Loans Total | 106 |
Revolving Loans | 0 |
Grand Total | 106 |
Loans |  | 4,350
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Commercial Real Estate Portfolio Segment [Member] | Loss [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | 0
Residential Portfolio Segment [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 38,656 |
2022 | 67,385 |
2021 | 29,430 |
2020 | 17,023 |
2019 | 13,292 |
Prior | 42,319 |
Term Loans Total | 208,105 |
Revolving Loans | 48,243 |
Grand Total | 256,348 |
Current year-to-date gross write-offs, 2023 | 0 |
Current year-to-date gross write-offs, 2022 | 27 |
Current year-to-date gross write-offs, 2021 | 0 |
Current year-to-date gross write-offs, 2020 | 0 |
Current year-to-date gross write-offs, 2019 | 0 |
Financing Receivable Originated Writeoffs Five or More Years Before Latest Fiscal Year, Total | 1 |
Current year-to-date gross write-offs, Term Loans Total | 28 |
Current year-to-date gross write-offs, Revolving Loans | 0 |
Current year-to-date gross write-offs, Grand Total | 28 |
Loans | 256,348 | 229,916
Total nonaccrual loans | 1,567 | 1,263
Residential Portfolio Segment [Member] | Performing Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 38,656 |
2022 | 66,921 |
2021 | 29,360 |
2020 | 17,023 |
2019 | 13,292 |
Prior | 41,778 |
Term Loans Total | 207,030 |
Revolving Loans | 47,751 |
Grand Total | 254,781 |
Loans |  | 228,653
Residential Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans |  | $ 0
Residential Portfolio Segment [Member] | Nonaccrual Financing Receivable [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 464 |
2021 | 70 |
2020 | 0 |
2019 | 0 |
Prior | 541 |
Term Loans Total | 1,075 |
Revolving Loans | 492 |
Grand Total | 1,567 |
Loans to other financial institutions [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 23,763 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 23,763 |
Revolving Loans | 0 |
Grand Total | 23,763 |
Current year-to-date gross write-offs, 2023 | 0 |
Current year-to-date gross write-offs, 2022 | 0 |
Current year-to-date gross write-offs, 2021 | 0 |
Current year-to-date gross write-offs, 2020 | 0 |
Current year-to-date gross write-offs, 2019 | 0 |
Financing Receivable Originated Writeoffs Five or More Years Before Latest Fiscal Year, Total | 0 |
Current year-to-date gross write-offs, Term Loans Total | 0 |
Current year-to-date gross write-offs, Revolving Loans | 0 |
Current year-to-date gross write-offs, Grand Total | 0 |
Loans | 23,763 |
Loans to other financial institutions [Member] | Performing Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 23,763 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 23,763 |
Revolving Loans | 0 |
Grand Total | 23,763 |
Loans to other financial institutions [Member] | Nonperforming Financial Instruments [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Term Loans Total | 0 |
Revolving Loans | 0 |
Grand Total | 0 |
Loans to other financial institutions [Member] | Nonaccrual Financing Receivable [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
2023 | 0 |
2022 | 0 |
2021 | 0 |
2020 | 0 |
2019 | 0 |
Prior | 0 |
Revolving Loans | 0 |
Grand Total | $ 0 |

X
- Definition Financing receivable originated writeoffs five or more years before latest fiscal year. + References No definition available. + Details
Name: | cofs_FinancingReceivableOriginatedWriteoffsFiveOrMoreYearsBeforeLatestFiscalYear
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing receivable originated writeoffs four years before latest fiscal year. + References No definition available. + Details
Name: | cofs_FinancingReceivableOriginatedWriteoffsFourYearsBeforeLatestFiscalYear
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing receivable originated writeoffs in current fiscal year. + References No definition available. + Details
Name: | cofs_FinancingReceivableOriginatedWriteoffsInCurrentFiscalYear
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing receivable originated writeoffs in fiscal year before latest fiscal year. + References No definition available. + Details
Name: | cofs_FinancingReceivableOriginatedWriteoffsInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing receivable originated writeoffs three years before latest fiscal year. + References No definition available. + Details
Name: | cofs_FinancingReceivableOriginatedWriteoffsThreeYearsBeforeLatestFiscalYear
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing receivable originated writeoffs two years before latest fiscal year. + References No definition available. + Details
Name: | cofs_FinancingReceivableOriginatedWriteoffsTwoYearsBeforeLatestFiscalYear
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Financing receivable writeoff revolving converted to term loan. + References No definition available. + Details
Name: | cofs_FinancingReceivableWriteoffRevolvingConvertedToTermLoan
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Writeoff of notes receivable gross. + References No definition available. + Details
Name: | cofs_WriteoffOfNotesReceivableGross
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Wriyeoff of financing receivable revolving. + References No definition available. + Details
Name: | cofs_WriyeoffOfFinancingReceivableRevolving
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amortized cost of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated in current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (3) -Publisher SEC Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (2) -Publisher SEC Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-7 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of financing receivable that can be withdrawn, repaid, and redrawn. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableRevolving
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of revolving financing receivable converted to term loan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6A -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6A + Details
Name: | us-gaap_FinancingReceivableRevolvingConvertedToTermLoan
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481990/310-10-45-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-4 + Details
Name: | us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 80 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-80 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479294/326-20-55-79 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (1) -Publisher SEC Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (2) -Publisher SEC Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Name Regulation S-K (SK) -Number 229 -Section 1404 -Paragraph (a) -Publisher SEC Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-14 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 7A -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-7A Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cofs_AgriculturalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_DoubtfulMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_UnlikelyToBeCollectedFinancingReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cofs_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cofs_ConstructionRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_PerformingFinancingReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_NonperformingFinancingReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=cofs_NonaccrualFinancingReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cofs_LoansToOtherFinancialInstitutionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |