Note 12 - Other Comprehensive Income (Loss) (Details Textual) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($)
Other Comprehensive Income (Loss), Remeasurement of Deferred Tax Assets and Liabilities	$ 506

Amount of remeasurement of deferred tax assets and liabilities included in other comprehensive income (loss).

No definition available.

Name:	sybt_OtherComprehensiveIncomeLossRemeasurementOfDeferredTaxAssetsAndLiabilities
Namespace Prefix:	sybt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration