v3.26.1
Employee Benefit Plan, Fair Value and NAV (Details) - EBP 002 - USD ($)
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
EBP, Investment, Fair Value and NAV [Line Items]    
EBP, Investment, Level 3 Reconciliation, Increase from Transfer into Level 3 $ 0  
EBP, Investment, Level 3 Reconciliation, Decrease from Transfer out of Level 3 0  
Investments, at fair value (See Note 3) 1,311,512,712 $ 1,170,324,448
BOKF common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 51,063,570 50,765,240
Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 771,026,816 709,523,023
Self-directed brokerage accounts    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 92,085,693 77,916,987
Collective investment funds measured at NAV1    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) [1] 397,336,633 332,119,198
Fair Value, Inputs, Level 1 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 910,311,673 834,844,677
Fair Value, Inputs, Level 1 [Member] | BOKF common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 51,063,570 50,765,240
Fair Value, Inputs, Level 1 [Member] | Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 771,026,816 709,523,023
Fair Value, Inputs, Level 1 [Member] | Self-directed brokerage accounts    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 88,221,287 74,556,414
Fair Value, Inputs, Level 2 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 3,864,406 3,360,573
Fair Value, Inputs, Level 2 [Member] | BOKF common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 0 0
Fair Value, Inputs, Level 2 [Member] | Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 0 0
Fair Value, Inputs, Level 2 [Member] | Self-directed brokerage accounts    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 3,864,406 3,360,573
Fair Value, Inputs, Level 3 [Member]    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 0 0
Fair Value, Inputs, Level 3 [Member] | BOKF common stock    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 0 0
Fair Value, Inputs, Level 3 [Member] | Registered investment companies    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) 0 0
Fair Value, Inputs, Level 3 [Member] | Self-directed brokerage accounts    
EBP, Investment, Fair Value and NAV [Line Items]    
Investments, at fair value (See Note 3) $ 0 $ 0
[1] In accordance with Subtopic 820-10, certain investments that were measured at NAV per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the statements of net assets available for benefits.