XML 29 R19.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Qualified Affordable Housing Projects | 6 Months Ended
--- | ---
Jun. 30, 2018
Investments in Affordable Housing Projects [Abstract] |
QUALIFIED AFFORDABLE HOUSING PROJECTS | QUALIFIED AFFORDABLE HOUSING PROJECTS We invest in affordable housing projects primarily to satisfy our Community Reinvestment Act requirements. As a limited partner in these operating partnerships, we receive tax credits and tax deductions for losses incurred by the underlying properties. We use the cost method to account for these partnerships. Our total investment in qualified affordable housing projects was $7.3 million at June 30, 2018 and $8.7 million at December 31, 2017. Amortization expense, included in other noninterest expense in the Consolidated Statements of Comprehensive Income was $0.7 million and $1.4 million for the three and six months ended June 30, 2018 and $0.8 million and $1.6 million for the three and six months ended June 30, 2017. The amortization expense was offset by tax credits of $0.8 million and $1.5 million for the three and six months ended June 30, 2018 and $0.9 million and $1.7 million for the three and six months ended June 30, 2017 as a reduction to our federal tax provision.

X
- Definition Qualified Affordable Housing Projects, Cost Method Accounting [Text Block] + References No definition available. + Details
Name: | stba_QualifiedAffordableHousingProjectsCostMethodAccountingTextBlock
Namespace Prefix: | stba_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsInAffordableHousingProjectsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration