XML 99 R86.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Loans and Allowance for Credit Losses - Allowance for Credit Loss Activity (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | $ 101,340 | $ 98,576
Provision for credit losses on loans | 19,240 | 5,359
Charge-offs | (24,638) | (11,617)
Recoveries | 11,456 | 9,022
Net (Charge-offs)/Recoveries | (13,182) | (2,595)
Balance at End of Period | 107,966 | 101,340
Cumulative Effect, Period of Adoption, Adjustment |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 568 |
Balance at End of Period |  | 568
Commercial Loans | Commercial real estate |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 41,428 | 50,700
Provision for credit losses on loans | (2,803) | (9,064)
Charge-offs | (1,706) | (827)
Recoveries | 967 | 619
Net (Charge-offs)/Recoveries | (739) | (208)
Balance at End of Period | 37,886 | 41,428
Commercial Loans | Commercial real estate | Cumulative Effect, Period of Adoption, Adjustment |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 0 |
Balance at End of Period |  | 0
Commercial Loans | Commercial and industrial |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 25,710 | 19,727
Provision for credit losses on loans | 18,366 | 4,797
Charge-offs | (19,254) | (5,797)
Recoveries | 9,641 | 6,983
Net (Charge-offs)/Recoveries | (9,613) | 1,186
Balance at End of Period | 34,538 | 25,710
Commercial Loans | Commercial and industrial | Cumulative Effect, Period of Adoption, Adjustment |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 75 |
Balance at End of Period |  | 75
Commercial Loans | Commercial construction |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 6,264 | 5,355
Provision for credit losses on loans | (648) | 908
Charge-offs | (451) | 0
Recoveries | 2 | 1
Net (Charge-offs)/Recoveries | (449) | 1
Balance at End of Period | 5,382 | 6,264
Commercial Loans | Commercial construction | Cumulative Effect, Period of Adoption, Adjustment |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 215 |
Balance at End of Period |  | 215
Commercial Loans | Business banking |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 12,547 | 11,338
Provision for credit losses on loans | 1,088 | 3,644
Charge-offs | (1,306) | (3,314)
Recoveries | 278 | 879
Net (Charge-offs)/Recoveries | (1,028) | (2,435)
Balance at End of Period | 12,858 | 12,547
Commercial Loans | Business banking | Cumulative Effect, Period of Adoption, Adjustment |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 251 |
Balance at End of Period |  | 251
Consumer Loans | Consumer real estate |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 12,105 | 8,733
Provision for credit losses on loans | 2,493 | 3,536
Charge-offs | (421) | (304)
Recoveries | 208 | 140
Net (Charge-offs)/Recoveries | (213) | (164)
Balance at End of Period | 14,663 | 12,105
Consumer Loans | Consumer real estate | Cumulative Effect, Period of Adoption, Adjustment |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 278 |
Balance at End of Period |  | 278
Consumer Loans | Other consumer |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | 3,286 | 2,723
Provision for credit losses on loans | 744 | 1,538
Charge-offs | (1,500) | (1,375)
Recoveries | 360 | 400
Net (Charge-offs)/Recoveries | (1,140) | (975)
Balance at End of Period | 2,639 | 3,286
Consumer Loans | Other consumer | Cumulative Effect, Period of Adoption, Adjustment |  |
Financing Receivable, Allowance for Credit Loss [Roll Forward] |  |
Balance at beginning of period | $ (251) |
Balance at End of Period |  | $ (251)

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of decrease (increase) in allowance for credit loss on financing receivable from writeoff (recovery). Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableExcludingAccruedInterestCreditLossExpenseReversal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=stba_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=stba_BusinessBankingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=stba_ConsumerRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=stba_OtherConsumerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |