XML 40 R31.htm IDEA: XBRL DOCUMENT
v3.23.3

Securities - Schedule of Maturities of Securities (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | $ 16,364 |
1 Year - 5 Years | 132,625 |
5 Years - 10 Years | 170,733 |
More than 10 Years | 171,082 |
Fair value, available for sale | 490,804 | $ 529,749
Total Available for Sale | 490,804 |
Held to Maturity Securities maturing within Less than 1 Year | 15,809 |
Held to Maturity Securities maturing within 1 Year -5 Years | 43,702 |
Held to Maturity Securities maturing within 5 Years -10 Years | 249,135 |
Held to Maturity Securities maturing within More than10 Years | 106,097 |
Held to Maturity Securities maturing within amortized cost | 414,743 |
U.S. Government and Federal Agency [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | 0 |
1 Year - 5 Years | 0 |
5 Years - 10 Years | 0 |
More than 10 Years | 0 |
Fair value, available for sale | 0 |
Held to Maturity Securities maturing within Less than 1 Year | 0 |
Held to Maturity Securities maturing within 1 Year -5 Years | 2,971 |
Held to Maturity Securities maturing within 5 Years -10 Years | 0 |
Held to Maturity Securities maturing within More than10 Years | 0 |
Held to Maturity Securities maturing within amortized cost | 2,971 |
U.S. Treasury Notes and Bonds [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | 0 |
1 Year - 5 Years | 55,662 |
5 Years - 10 Years | 21,370 |
More than 10 Years | 0 |
Fair value, available for sale | 77,032 | 78,204
State and Municipal [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | 1,854 |
1 Year - 5 Years | 9,677 |
5 Years - 10 Years | 36,082 |
More than 10 Years | 165,101 |
Fair value, available for sale | 212,714 | 229,938
Held to Maturity Securities maturing within Less than 1 Year | 1,056 |
Held to Maturity Securities maturing within 1 Year -5 Years | 9,425 |
Held to Maturity Securities maturing within 5 Years -10 Years | 80,002 |
Held to Maturity Securities maturing within More than10 Years | 106,097 |
Held to Maturity Securities maturing within amortized cost | 196,580 |
Corporate [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | 509 |
1 Year - 5 Years | 0 |
5 Years - 10 Years | 200 |
More than 10 Years | 0 |
Fair value, available for sale | 709 | 711
Held to Maturity Securities maturing within Less than 1 Year | 0 |
Held to Maturity Securities maturing within 1 Year -5 Years | 0 |
Held to Maturity Securities maturing within 5 Years -10 Years | 20,005 |
Held to Maturity Securities maturing within More than10 Years | 0 |
Held to Maturity Securities maturing within amortized cost | 20,005 |
Asset-backed Securities [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | 0 |
1 Year - 5 Years | 8,195 |
5 Years - 10 Years | 3,090 |
More than 10 Years | 0 |
Fair value, available for sale | 11,285 | 12,333
Held to Maturity Securities maturing within Less than 1 Year | 0 |
Held to Maturity Securities maturing within 1 Year -5 Years | 642 |
Held to Maturity Securities maturing within 5 Years -10 Years | 0 |
Held to Maturity Securities maturing within More than10 Years | 0 |
Held to Maturity Securities maturing within amortized cost | 642 |
Total debt securities [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | 2,363 |
1 Year - 5 Years | 73,534 |
5 Years - 10 Years | 60,742 |
More than 10 Years | 165,101 |
Fair value, available for sale | 301,740 |
Held to Maturity Securities maturing within Less than 1 Year | 1,056 |
Held to Maturity Securities maturing within 1 Year -5 Years | 13,038 |
Held to Maturity Securities maturing within 5 Years -10 Years | 100,007 |
Held to Maturity Securities maturing within More than10 Years | 106,097 |
Held to Maturity Securities maturing within amortized cost | 220,198 |
Mortgage-backed [Member] |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Less than 1 Year | 14,001 |
1 Year - 5 Years | 59,091 |
5 Years - 10 Years | 109,991 |
More than 10 Years | 5,981 |
Fair value, available for sale | 189,064 | $ 208,563
Held to Maturity Securities maturing within Less than 1 Year | 14,753 |
Held to Maturity Securities maturing within 1 Year -5 Years | 30,664 |
Held to Maturity Securities maturing within 5 Years -10 Years | 149,128 |
Held to Maturity Securities maturing within More than10 Years | 0 |
Held to Maturity Securities maturing within amortized cost | $ 194,545 |

X
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), and equity security measured at fair value with change in fair value recognized in net income (FV-NI), with single maturity date and allocated without single maturity date, maturing after rolling tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References No definition available. + Details
Name: | cofs_AvailableForSaleSecuritiesDebtAndEquitySecuritiesFvNiMaturitiesRollingAfterYearTenFairValue
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), maturing in rolling sixth through tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References No definition available. + Details
Name: | cofs_DebtSecuritiesAvailableforsaleAndEquitySecuritiesFVNIMaturityRollingAfterFiveThroughTenYearsFairValue
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), maturing in rolling second through fifth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References No definition available. + Details
Name: | cofs_DebtSecuritiesAvailableforsaleAndEquitySecuritiesFVNIMaturityRollingAfterOneThroughFiveYearsFairValue
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), maturing in next rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. + References No definition available. + Details
Name: | cofs_DebtSecuritiesAvailableforsaleAndEquitySecuritiesFVNIMaturityRollingWithinOneYearFairValue
Namespace Prefix: | cofs_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (aa) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481830/320-10-45-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479130/326-30-45-1 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year following current statement of financial position date. For interim and annual periods when interim period is reported on rolling approach. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing after rolling tenth fiscal year following current statement of financial position date. For interim and annual periods when interim period is reported on rolling approach. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in sixth through tenth rolling fiscal year following current statement of financial position date. For interim and annual periods when interim period is reported on rolling approach. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in second through fifth rolling fiscal year following current statement of financial position date. For interim and annual periods when interim period is reported on rolling approach. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sum of the carrying amounts as of the balance sheet date of all investments. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)(h)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1 + Details
Name: | us-gaap_Investments
Namespace Prefix: | us-gaap_
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_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |