Fair Value Measurements Fair Value Measurement, Measured On Non-Recurring Basis, Signfiicant Unobservable Inputs, Quantitative Information (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	Dec. 31, 2022		Dec. 31, 2021
Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member] | BOK Financial Pension Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Defined Benefit Plan, Plan Assets, Amount			$ 39,000
Fair Value, Nonaccruing Loans | Fair Value, Inputs, Level 2 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 57		808
Real estate and other repossessed assets [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure			0
Real estate and other repossessed assets [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	3,873		1,706
Discounted Cash Flow [Member] | Fair Value, Nonaccruing Loans | Fair Value, Inputs, Level 3 [Member] | Management knowledge of Industry [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	4,998		$ 1,990
Discounted Cash Flow [Member] | Real estate and other repossessed assets [Member] | Fair Value, Inputs, Level 3 [Member] | Management knowledge of Industry [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 1,699
Minimum [Member] | Fair Value, Nonaccruing Loans | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value of Impaired Loans as Percentage of Unpaid Principal Balance	9.00%	[1]	16.00%	[2]
Maximum [Member] | Fair Value, Nonaccruing Loans | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value of Impaired Loans as Percentage of Unpaid Principal Balance	24.00%	[1]	97.00%	[2]
Weighted Average [Member] | Fair Value, Nonaccruing Loans | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value of Impaired Loans as Percentage of Unpaid Principal Balance	23.00%	[1]	37.00%	[2]

[1] Represents fair value as a percentage of the unpaid principal balance.

[2] Represents fair value as a percentage of the unpaid principal balance.