v3.26.1
Schedule H, Line 4i – Schedule of Assets (Held At End of Year) (Details) - EBP 002
 12 Months Ended
Dec. 31, 2025
USD ($)
shares
EBP, Schedule of Asset Held for Investment [Line Items]  
Entity tax identification number 25-0776600
Plan number 002
Total assets held at end of year $ 144,188,868
Mutual funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
Total assets held at end of year $ 123,475,784
Investment, Identifier [Axis]: American Funds 2010 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 26
Total assets held at end of year $ 310
Investment, Identifier [Axis]: American Funds 2015 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 10,638
Total assets held at end of year $ 137,023
Investment, Identifier [Axis]: American Funds 2020 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 53,434
Total assets held at end of year $ 760,368
Investment, Identifier [Axis]: American Funds 2025 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 94,075
Total assets held at end of year $ 1,520,259
Investment, Identifier [Axis]: American Funds 2030 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 218,052
Total assets held at end of year $ 4,092,832
Investment, Identifier [Axis]: American Funds 2035 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 230,298
Total assets held at end of year $ 4,836,253
Investment, Identifier [Axis]: American Funds 2040 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 159,677
Total assets held at end of year $ 3,694,926
Investment, Identifier [Axis]: American Funds 2045 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 171,694
Total assets held at end of year $ 4,132,674
Investment, Identifier [Axis]: American Funds 2050 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 152,932
Total assets held at end of year $ 3,630,585
Investment, Identifier [Axis]: American Funds 2055 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 47,801
Total assets held at end of year $ 1,440,717
Investment, Identifier [Axis]: American Funds 2060 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 51,026
Total assets held at end of year $ 1,047,058
Investment, Identifier [Axis]: American Funds 2065 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 31,041
Total assets held at end of year $ 626,415
Investment, Identifier [Axis]: American Funds 2070 Trgt Dt Ret R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 8,368
Total assets held at end of year $ 108,029
Investment, Identifier [Axis]: American Funds Fundamental Investors Fund R5  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 135,835
Total assets held at end of year $ 12,487,281
Investment, Identifier [Axis]: Brandes Emerging Markets Value Fund I  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 44,055
Total assets held at end of year $ 1,281,108
Investment, Identifier [Axis]: Dodge & Cox Income X  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 93,536
Total assets held at end of year $ 1,202,876
Investment, Identifier [Axis]: Dodge & Cox Stock X  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 80,664
Total assets held at end of year $ 1,338,209
Investment, Identifier [Axis]: Dodge & Cox Balanced Fund X  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 2,089,045
Total assets held at end of year $ 28,202,106
Investment, Identifier [Axis]: Emerald Growth Institutional  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 11,364
Total assets held at end of year $ 341,947
Investment, Identifier [Axis]: Federated Short-Intermediate Total Ret Bond Fund R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 58,041
Total assets held at end of year $ 593,182
Investment, Identifier [Axis]: Fidelity 500 Index  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 96,529
Total assets held at end of year $ 22,946,980
Investment, Identifier [Axis]: Fidelity International Index  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 83,118
Total assets held at end of year $ 5,053,602
Investment, Identifier [Axis]: Fidelity Mid Cap Index  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 374,155
Total assets held at end of year $ 13,817,527
Investment, Identifier [Axis]: Merger I  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 11,885
Total assets held at end of year $ 1,027,346
Investment, Identifier [Axis]: Neuberger Berman International Equity R6  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 80,762
Total assets held at end of year $ 5,423,998
Investment, Identifier [Axis]: PIMCO Total Return Institutional  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 421,235
Total assets held at end of year $ 3,732,173
Investment, Identifier [Axis]: S&T Bancorp, Inc. Common Stock  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 354,390
Total assets held at end of year $ 13,945,243
Investment, Identifier [Axis]: Vanguard Treasury Money Market Investor Shares  
EBP, Schedule of Asset Held for Investment [Line Items]  
Number of Units or Shares Held | shares 6,767,841
Total assets held at end of year $ 6,767,841