Note 1 - Summary of Significant Accounting Policies (Details Textual)	6 Months Ended
Jun. 30, 2017
Period Look-back, Quarters	24
Period Look-back, Extended, Quarters	28

Represents the number of quarters for the extended look-back period for the critical accounting policy related to allowance and provision for loan losses.

No definition available.

Name:	sybt_PeriodLookbackExtendedQuarters
Namespace Prefix:	sybt_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration