Note 1 - Summary of Significant Accounting Policies (Details)	9 Months Ended
Sep. 30, 2015
Accounting Policies [Abstract]
Period Look-back	36 months
Period Look-back, Extended	72 months

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

No definition available.

Name:	sybt_PeriodLookBackExtended
Namespace Prefix:	sybt_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration