SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Business and Organization (Details)	12 Months Ended
Dec. 31, 2020 Branch
Business and Organization [Abstract]
Number of full service banking offices	30

The number of full service banking offices operated.

No definition available.

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