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 ($)
EBP, Schedule of Asset Held for Investment [Line Items]  
Entity tax identification number 25-1255406
Plan number 002
Participant Loans, Cost $ 0
Participant Loans 11,218,173
Total $ 596,961,309
Minimum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan, interest rate 4.25%
Maximum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Participant loan, interest rate 9.50%
Mutual fund investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value $ 468,567,203
F.N.B. Corporation Common Stock Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 117,165,090
Money market fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 10,843
Investment, Identifier [Axis]: Allspring Spl Mid Cap Value R6 | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 8,344,862
Investment, Identifier [Axis]: American Century Small Cap Value R6 | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 6,827,338
Investment, Identifier [Axis]: Baird Core Plus Inst | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 18,659,779
Investment, Identifier [Axis]: Baird Short term Bond IS | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 2,528,147
Investment, Identifier [Axis]: C&S Realty Shares Z | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 3,129,113
Investment, Identifier [Axis]: Fidelity 500 Index | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 60,798,290
Investment, Identifier [Axis]: Fidelity Blue Chip Growth K6 | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 48,095,551
Investment, Identifier [Axis]: Fidelity FDM Index 2010 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 1,533,618
Investment, Identifier [Axis]: Fidelity FDM Index 2015 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 630,708
Investment, Identifier [Axis]: Fidelity FDM Index 2020 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 7,062,780
Investment, Identifier [Axis]: Fidelity FDM Index 2025 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 16,972,114
Investment, Identifier [Axis]: Fidelity FDM Index 2030 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 31,462,853
Investment, Identifier [Axis]: Fidelity FDM Index 2035 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 25,173,016
Investment, Identifier [Axis]: Fidelity FDM Index 2040 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 27,327,990
Investment, Identifier [Axis]: Fidelity FDM Index 2045 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 26,205,037
Investment, Identifier [Axis]: Fidelity FDM Index 2050 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 18,458,169
Investment, Identifier [Axis]: Fidelity FDM Index 2055 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 13,822,010
Investment, Identifier [Axis]: Fidelity FDM Index 2060 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 9,491,358
Investment, Identifier [Axis]: Fidelity FDM Index 2065 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 3,410,882
Investment, Identifier [Axis]: Fidelity FDM Index 2070 IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 231,174
Investment, Identifier [Axis]: Fidelity FDM Index RET IPR | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 584,705
Investment, Identifier [Axis]: Fidelity Global Ex US Index | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 5,597,908
Investment, Identifier [Axis]: Fidelity International Cap Appr K6 | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 16,615,839
Investment, Identifier [Axis]: Fidelity Mid Cap Index | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 13,471,029
Investment, Identifier [Axis]: Fidelity Small Cap Growth K6 | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 8,901,585
Investment, Identifier [Axis]: Fidelity Small Cap Index | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 8,594,355
Investment, Identifier [Axis]: Fidelity Total Market Index | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 16,044,677
Investment, Identifier [Axis]: Fidelity US Bond Index | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 3,487,022
Investment, Identifier [Axis]: JPMorgan US Value R6 | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 19,503,074
Investment, Identifier [Axis]: MFS Mid Cap Growth R6 | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value 9,557,177
Investment, Identifier [Axis]: Vanguard Cr Fed Money Market Adm | Mutual Fund Investments  
EBP, Schedule of Asset Held for Investment [Line Items]  
Current value $ 36,045,043