SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Derivatives (Details)	12 Months Ended
Dec. 31, 2020 Derivative
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Number of types of derivatives	3

Number of types of derivatives based on the purpose of the contract and belief as to its effectiveness as a hedge.

No definition available.

Name:	czfs_NumberOfTypesOfDerivatives
Namespace Prefix:	czfs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration