XML 61 R48.htm IDEA: XBRL DOCUMENT
v3.19.1

Off-Balance Sheet Activities (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2018
Risks and Uncertainties [Abstract] |
Schedule of contractual amount of financial instruments with off-balance sheet risk | The contractual amount of financial instruments with off-balance sheet risk was as follows at December 31:
|  | 2018 |  |  | 2017 |
|  | Fixed |  |  | Variable |  |  | Fixed |  |  | Variable |
(Dollars in thousands) |  | Rate |  |  | Rate |  |  | Rate |  |  | Rate |
Unused lines of credit and letters of credit |  | $ | 20,036 |  |  | $ | 103,978 |  |  | $ | 9,033 |  |  | $ | 104,257 |
Commitments to fund loans (at market rates) |  |  | 20,997 |  |  |  | 1,421 |  |  |  | 8,633 |  |  |  | 1,225 |

X
- Definition Tabular disclosure of contractual amount of financial instruments with off-balance sheet risk. + References No definition available. + Details
Name: | cofs_CreditRiskConcentrationsTableTextBlock
Namespace Prefix: | cofs_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_RisksAndUncertaintiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration