XML 98 R62.htm IDEA: XBRL DOCUMENT
v3.20.1

Allowance for Credit Losses - Collateral Dependent Loans by Class of Loan (Details) - USD ($) $ in Thousands | Mar. 31, 2020 | Jan. 01, 2020
--- | --- | ---
Real Estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | $ 62,638 |
Blanket Lien |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 5,421 |
Investment/Cash |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 40 |
Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 689 |
Commercial | Commercial real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans |  | $ 3,416,518
Commercial | Commercial real estate | Real Estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 51,630 |
Commercial | Commercial real estate | Blanket Lien |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Commercial real estate | Investment/Cash |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Commercial real estate | Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Commercial and industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans |  | 1,720,833
Commercial | Commercial and industrial | Real Estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 4,686 |
Commercial | Commercial and industrial | Blanket Lien |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 4,545 |
Commercial | Commercial and industrial | Investment/Cash |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 40 |
Commercial | Commercial and industrial | Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Commercial construction |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans |  | 375,445
Commercial | Commercial construction | Real Estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 3,602 |
Commercial | Commercial construction | Blanket Lien |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Commercial construction | Investment/Cash |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Commercial construction | Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Business banking |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans |  | $ 0
Commercial | Business banking | Real Estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 2,322 |
Commercial | Business banking | Blanket Lien |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 876 |
Commercial | Business banking | Investment/Cash |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Business banking | Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 689 |
Commercial | Consumer real estate | Real Estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Consumer real estate | Blanket Lien |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Consumer real estate | Investment/Cash |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Consumer real estate | Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Other consumer | Real Estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 398 |
Commercial | Other consumer | Blanket Lien |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Other consumer | Investment/Cash |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | 0 |
Commercial | Other consumer | Other |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Collateral dependent loans | $ 0 |

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

X
- Definition Amount, before allowance for credit loss, of financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919230-210447 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_CollateralAxis=us-gaap_RealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=stba_BlanketLienMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=stba_InvestmentAndCashCollateralMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollateralAxis=stba_OtherCollateralMember
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_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: |