XML 100 R86.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Right-of-Use Assets and Lease Liabilities - Narrative (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($) lease | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
Leases [Abstract] |  |  |
Number of lease contracts | 41 |  |
Number of operating lease agreements | 39 |  |
Number of financing leases | 2 |  |
Operating lease expense | $ | $ 0.2 | $ 0.2 | $ 0.2
Number of new lease agreements in the period | 1 |  |

X
- Definition Lessee, Finance Leases, Number Of Lease Agreements + References No definition available. + Details
Name: | stba_LesseeFinanceLeasesNumberOfLeaseAgreements
Namespace Prefix: | stba_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Lessee, Number Of Leases + References No definition available. + Details
Name: | stba_LesseeNumberOfLeases
Namespace Prefix: | stba_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Lessee, Number Of Leases, New + References No definition available. + Details
Name: | stba_LesseeNumberOfLeasesNew
Namespace Prefix: | stba_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Lessee, Operating Leases, Number Of Lease Agreements + References No definition available. + Details
Name: | stba_LesseeOperatingLeasesNumberOfLeaseAgreements
Namespace Prefix: | stba_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition Amount of operating lease expense. Excludes sublease income. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 4 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479041/842-20-45-4 + Details
Name: | us-gaap_OperatingLeaseExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration