XML 44 R35.htm IDEA: XBRL DOCUMENT
v3.23.2

Loans and Allowance for Credit Losses - Allowance for Credit Losses and Balances in Loan Portfolio (Details) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022 | Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | $ 15,065,000 | $ 7,601,000 | $ 7,619,000 | $ 7,688,000 |
Charge-offs | (131,000) | (244,000) | (271,000) | (386,000) |
Recoveries | 63,000 | 59,000 | 176,000 | 114,000 |
Provision | (415,000) | 0 | (106,000) | 0 |
Ending balance | 14,582,000 | 7,416,000 | 14,582,000 | 7,416,000 |
Individually evaluated for credit loss |  | 215,000 |  | 215,000 | $ 153,000
Collectively evaluated for credit loss |  | 7,201,000 |  | 7,201,000 | 7,466,000
Individually evaluated for credit loss | 72,000 |  | 72,000 |  |
Collectively evaluated for credit loss | 14,510,000 |  | 14,510,000 |  |
Individually evaluated for impairment |  |  |  |  | 2,846,000
Collectively evaluated for impairment |  |  |  |  | 1,172,662,000
Individually evaluated for credit loss | 2,123,000 |  | 2,123,000 |  |
Collectively evaluated for credit loss | 1,262,105,000 |  | 1,262,105,000 |  |
Acquired with deteriorated credit quality |  |  |  |  | 14,274,000
Loans | 1,264,228,000 |  | 1,264,228,000 |  | 1,189,782,000
Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | 7,165,000 |  |
Agricultural [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | 136,000 | 387,000 | 144,000 | 448,000 |
Charge-offs | 0 |  | 0 |  |
Recoveries | 0 |  | 0 |  |
Provision | (58,000) | (255,000) | (80,000) | (316,000) |
Ending balance | 78,000 | 132,000 | 78,000 | 132,000 |
Individually evaluated for credit loss |  | 1,000 |  | 1,000 | 2,000
Collectively evaluated for credit loss |  | 131,000 |  | 131,000 | 142,000
Individually evaluated for credit loss | 1,000 |  | 1,000 |  |
Collectively evaluated for credit loss | 77,000 |  | 77,000 |  |
Individually evaluated for impairment |  |  |  |  | 23,000
Collectively evaluated for impairment |  |  |  |  | 64,136,000
Individually evaluated for credit loss | 17,000 |  | 17,000 |  |
Collectively evaluated for credit loss | 40,667,000 |  | 40,667,000 |  |
Acquired with deteriorated credit quality |  |  |  |  | 0
Loans | 40,684,000 |  | 40,684,000 |  | 64,159,000
Agricultural [Member] | Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | 14,000 |  |
Commercial and Industrial [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | 3,020,000 | 1,752,000 | 1,361,000 | 1,454,000 |
Charge-offs | 0 | (100,000) | 0 | (131,000) |
Recoveries | 2,000 | 2,000 | 29,000 | 4,000 |
Provision | (126,000) | (41,000) | (81,000) | 286,000 |
Ending balance | 2,896,000 | 1,613,000 | 2,896,000 | 1,613,000 |
Individually evaluated for credit loss |  | 52,000 |  | 52,000 | 14,000
Collectively evaluated for credit loss |  | 1,561,000 |  | 1,561,000 | 1,347,000
Individually evaluated for credit loss | 34,000 |  | 34,000 |  |
Collectively evaluated for credit loss | 2,862,000 |  | 2,862,000 |  |
Individually evaluated for impairment |  |  |  |  | 177,000
Collectively evaluated for impairment |  |  |  |  | 206,074,000
Individually evaluated for credit loss | 318,000 |  | 318,000 |  |
Collectively evaluated for credit loss | 223,873,000 |  | 223,873,000 |  |
Acquired with deteriorated credit quality |  |  |  |  | 3,959,000
Loans | 224,191,000 |  | 224,191,000 |  | 210,210,000
Commercial and Industrial [Member] | Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | 1,587,000 |  |
Consumer Portfolio Segment [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | 913,000 | 304,000 | 310,000 | 290,000 |
Charge-offs | (131,000) | (144,000) | (271,000) | (255,000) |
Recoveries | 59,000 | 55,000 | 129,000 | 106,000 |
Provision | 44,000 | 94,000 | 176,000 | 168,000 |
Ending balance | 885,000 | 309,000 | 885,000 | 309,000 |
Individually evaluated for credit loss |  | 1,000 |  | 1,000 | 1,000
Collectively evaluated for credit loss |  | 308,000 |  | 308,000 | 309,000
Individually evaluated for credit loss | 0 |  | 0 |  |
Collectively evaluated for credit loss | 885,000 |  | 885,000 |  |
Individually evaluated for impairment |  |  |  |  | 7,000
Collectively evaluated for impairment |  |  |  |  | 39,793,000
Individually evaluated for credit loss | 0 |  | 0 |  |
Collectively evaluated for credit loss | 38,614,000 |  | 38,614,000 |  |
Acquired with deteriorated credit quality |  |  |  |  | 8,000
Loans | 38,614,000 |  | 38,614,000 |  | 39,808,000
Consumer Portfolio Segment [Member] | Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | 541,000 |  |
Commercial Real Estate Portfolio Segment [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | 7,837,000 | 3,690,000 | 4,822,000 | 3,705,000 |
Charge-offs | 0 | 0 | 0 |  |
Recoveries | 0 | 1,000 | 13,000 | 2,000 |
Provision | (600,000) | 533,000 | (604,000) | 517,000 |
Ending balance | 7,237,000 | 4,224,000 | 7,237,000 | 4,224,000 |
Individually evaluated for credit loss |  | 7,000 |  | 7,000 | 5,000
Collectively evaluated for credit loss |  | 4,217,000 |  | 4,217,000 | 4,817,000
Individually evaluated for credit loss | 1,000 |  | 1,000 |  |
Collectively evaluated for credit loss | 7,236,000 |  | 7,236,000 |  |
Individually evaluated for impairment |  |  |  |  | 165,000
Collectively evaluated for impairment |  |  |  |  | 622,131,000
Individually evaluated for credit loss | 32,000 |  | 32,000 |  |
Collectively evaluated for credit loss | 657,517,000 |  | 657,517,000 |  |
Acquired with deteriorated credit quality |  |  |  |  | 8,657,000
Loans | 657,549,000 |  | 657,549,000 |  | 630,953,000
Commercial Real Estate Portfolio Segment [Member] | Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | 3,006,000 |  |
Construction Real Estate [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | 72,000 | 37,000 | 63,000 | 110,000 |
Charge-offs | 0 |  | 0 |  |
Recoveries | 0 |  | 0 |  |
Provision | (2,000) | 8,000 | (13,000) | (65,000) |
Ending balance | 70,000 | 45,000 | 70,000 | 45,000 |
Individually evaluated for credit loss |  | 0 |  | 0 | 0
Collectively evaluated for credit loss |  | 45,000 |  | 45,000 | 63,000
Individually evaluated for credit loss | 0 |  | 0 |  |
Collectively evaluated for credit loss | 70,000 |  | 70,000 |  |
Individually evaluated for impairment |  |  |  |  | 0
Collectively evaluated for impairment |  |  |  |  | 14,736,000
Individually evaluated for credit loss | 0 |  | 0 |  |
Collectively evaluated for credit loss | 16,734,000 |  | 16,734,000 |  |
Acquired with deteriorated credit quality |  |  |  |  | 0
Loans | 16,734,000 |  | 16,734,000 |  | 14,736,000
Construction Real Estate [Member] | Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | 20,000 |  |
Residential Portfolio Segment [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | 3,087,000 | 589,000 | 906,000 | 671,000 |
Charge-offs | 0 | 0 | 0 |  |
Recoveries | 2,000 | 1,000 | 5,000 | 2,000 |
Provision | 287,000 | 101,000 | 455,000 | 18,000 |
Ending balance | 3,376,000 | 691,000 | 3,376,000 | 691,000 |
Individually evaluated for credit loss |  | 154,000 |  | 154,000 | 131,000
Collectively evaluated for credit loss |  | 537,000 |  | 537,000 | 775,000
Individually evaluated for credit loss | 36,000 |  | 36,000 |  |
Collectively evaluated for credit loss | 3,340,000 |  | 3,340,000 |  |
Individually evaluated for impairment |  |  |  |  | 2,474,000
Collectively evaluated for impairment |  |  |  |  | 225,792,000
Individually evaluated for credit loss | 1,756,000 |  | 1,756,000 |  |
Collectively evaluated for credit loss | 245,862,000 |  | 245,862,000 |  |
Acquired with deteriorated credit quality |  |  |  |  | 1,650,000
Loans | 247,618,000 |  | 247,618,000 |  | 229,916,000
Residential Portfolio Segment [Member] | Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | 2,010,000 |  |
Loans To Other Financial Institutions [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Provision | 40,000 |  | 40,000 |  |
Ending balance | 40,000 |  | 40,000 |  |
Collectively evaluated for credit loss | 40,000 |  | 40,000 |  |
Collectively evaluated for credit loss | 38,838,000 |  | 38,838,000 |  |
Loans | 38,838,000 |  | 38,838,000 |  |
Unallocated Financing Receivables [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance | 0 | 842,000 | 13,000 | 1,010,000 |
Charge-offs | 0 |  | 0 |  |
Recoveries | 0 |  | 0 |  |
Provision | 0 | (440,000) | 0 | (608,000) |
Ending balance | 0 | 402,000 | 0 | 402,000 |
Individually evaluated for credit loss |  | 0 |  | 0 | 0
Collectively evaluated for credit loss |  | $ 402,000 |  | $ 402,000 | $ 13,000
Individually evaluated for credit loss | 0 |  | 0 |  |
Collectively evaluated for credit loss | $ 0 |  | 0 |  |
Unallocated Financing Receivables [Member] | Cumulative Effect of Change in Accounting Principle [Member] |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |
Beginning balance |  |  | $ (13,000) |  |

X
- Definition The balance of financing receivables that were acquired with deteriorated credit quality. + References No definition available. + Details
Name: | cofs_FinancingReceivableAcquiredWithDeterioratedCreditQuality
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing receivable, allowance for credit losses, collectively evaluated for credit loss. + References No definition available. + Details
Name: | cofs_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForCreditLoss
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing receivable, allowance for credit losses, individually evaluated for credit loss. + References No definition available. + Details
Name: | cofs_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForCreditLoss
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Collectively Evaluated For Credit loss. + References No definition available. + Details
Name: | cofs_FinancingReceivableCollectivelyEvaluatedForCreditLoss
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Financing Receivable Individually Evaluated For Credit Loss. + References No definition available. + Details
Name: | cofs_FinancingReceivableIndividuallyEvaluatedForCreditLoss
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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 The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (g) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (g) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase in allowance for credit loss on financing receivable from recovery. + 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 13 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(4) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of writeoff of financing receivable, charged against allowance for credit loss. + 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 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(3) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The balance of financing receivables that were collectively evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L(5)(a)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480418/310-10-S99-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11C -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11C + Details
Name: | us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The balance of financing receivables that were individually evaluated for impairment. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11C -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11C Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L(5)(a)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480418/310-10-S99-4 + Details
Name: | us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481696/310-30-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(1) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (g) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.1) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480418/310-10-S99-4 + Details
Name: | us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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 Amount of credit loss expense (reversal of expense) for financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(11)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1 + Details
Name: | us-gaap_ProvisionForLoanLossesExpensed
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cofs_AgriculturalMember
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=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=cofs_ConstructionRealEstateMember
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: |

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