XML 55 R46.htm IDEA: XBRL DOCUMENT
v3.23.1

Loans and Allowance for Credit Losses - Loans on Nonaccrual Status and Loans Past Due 90 Days or More and Still Accruing (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 | Dec. 31, 2022
Financing Receivable, Nonaccrual [Line Items] |  |
Beginning of Period Nonaccrual | $ 19,052 | $ 66,291
End of Period Nonaccrual | 24,644 | 19,052
Nonaccrual With No Related Allowance | 5,442 | 6,582
Interest income recognized on nonaccrual | 201 | 1,385
Commercial Loans | Commercial real estate |  |
Financing Receivable, Nonaccrual [Line Items] |  |
Beginning of Period Nonaccrual | 7,100 | 31,488
End of Period Nonaccrual | 7,425 | 7,100
Nonaccrual With No Related Allowance | 5,442 | 5,649
Interest income recognized on nonaccrual | 1 | 580
Commercial Loans | Commercial and industrial |  |
Financing Receivable, Nonaccrual [Line Items] |  |
Beginning of Period Nonaccrual | 283 | 15,239
End of Period Nonaccrual | 7,075 | 283
Nonaccrual With No Related Allowance | 0 | 0
Interest income recognized on nonaccrual | 0 | 148
Commercial Loans | Commercial construction |  |
Financing Receivable, Nonaccrual [Line Items] |  |
Beginning of Period Nonaccrual | 384 | 2,471
End of Period Nonaccrual | 384 | 384
Nonaccrual With No Related Allowance | 0 | 0
Interest income recognized on nonaccrual | 0 | 171
Commercial Loans | Business banking |  |
Financing Receivable, Nonaccrual [Line Items] |  |
Beginning of Period Nonaccrual | 4,490 | 9,641
End of Period Nonaccrual | 3,915 | 4,490
Nonaccrual With No Related Allowance | 0 | 933
Interest income recognized on nonaccrual | 108 | 228
Consumer Loans | Consumer real estate |  |
Financing Receivable, Nonaccrual [Line Items] |  |
Beginning of Period Nonaccrual | 6,526 | 7,294
End of Period Nonaccrual | 5,529 | 6,526
Nonaccrual With No Related Allowance | 0 | 0
Interest income recognized on nonaccrual | 91 | 257
Consumer Loans | Other consumer |  |
Financing Receivable, Nonaccrual [Line Items] |  |
Beginning of Period Nonaccrual | 269 | 158
End of Period Nonaccrual | 316 | 269
Nonaccrual With No Related Allowance | 0 | 0
Interest income recognized on nonaccrual | $ 1 | $ 1

X
- Definition Amount of interest income on financing receivable on nonaccrual status. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-16 + Details
Name: | us-gaap_FinancingReceivableNonaccrualInterestIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amortized cost of financing receivable on nonaccrual status with no allowance for credit loss. 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 16 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-16 + Details
Name: | us-gaap_FinancingReceivableNonaccrualNoAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 16 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-16 + Details
Name: | us-gaap_FinancingReceivableNonaccrualStatusLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amortized cost of financing receivable on nonaccrual status. 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 16 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-16 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (3) -Publisher SEC Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (2) -Publisher SEC Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-7 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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: |