XML 61 R26.htm IDEA: XBRL DOCUMENT
v3.21.1

Commitments and Contingencies (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract] |
Schedule of Commitments and Letters of Credit | The following table sets forth our commitments and letters of credit as of the dates presented:
(dollars in thousands) | March 31, 2021 |  | December 31, 2020 |
Commitments to extend credit |  | $ | 2,261,223 |  |  |  | $ | 2,185,752 |  |
Standby letters of credit |  | 88,418 |  |  |  | 89,095 |  |
Total |  | $ | 2,349,641 |  |  |  | $ | 2,274,847 |  |
Unfunded Loan Commitments, Allowance For Credit Loss | The following table presents activity in the allowance for credit losses on unfunded loan commitments as of the dates presented:
(dollars in thousands) | Three Months Ended March 31, 2021 |  | Three Months Ended March 31, 2020
Balance at beginning of period |  | $ | 4,467 |  |  |  | $ | 3,112 |
Impact of adopting ASU 2016-13 at January 1, 2020 |  | — |  |  |  | 1,349 |
Balance after adoption of ASU 2016-13 |  | 4,467 |  |  |  | 4,461 |
(Recovery) provision for credit losses |  | (164) |  |  |  | 1,616 |
Total |  | $ | 4,303 |  |  |  | $ | 6,077 |

X
- Definition Commitments and Letters of Credit [Table Text Block] + References No definition available. + Details
Name: | stba_CommitmentsandLettersofCreditTableTextBlock
Namespace Prefix: | stba_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Off Balance Sheet Liability, Allowance For Credit Loss + References No definition available. + Details
Name: | stba_OffBalanceSheetLiabilityAllowanceForCreditLossTableTextBlock
Namespace Prefix: | stba_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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