Parent Company Only Financial Statements Parent Company Only Financial Statements, Condensed Income Statements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Income Statements, Captions [Line Items]
Interest expense	$ 61,896	$ 160,556	$ 419,079
Other operating expense	1,177,708	1,164,308	1,133,244
Other gains (losses), net	63,742	6,046	10,214
Federal and state income taxes	179,775	128,793	130,183
Net income attributable to BOK Financial Corp. shareholders	618,121	435,030	500,758
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Total revenue	492,665	205,097	354,368
Interest expense	10,535	13,944	15,113
Other operating expense	2,914	2,697	2,352
Total expense	13,449	16,641	17,465
Net income before taxes, other losses, net, and equity in undistributed income of subsidiaries	479,216	188,456	336,903
Other gains (losses), net	(3,415)	1,465	3,310
Net income before taxes and equity in undistributed income of subsidiaries	475,801	189,921	340,213
Federal and state income taxes	(4,202)	(4,502)	(4,516)
Net income before equity in undistributed income of subsidiaries	480,003	194,423	344,729
Equity in undistributed income of bank subsidiaries	126,380	276,217	166,797
Equity in undistributed income of non-bank subsidiaries	11,738	(35,610)	(10,768)
Net income attributable to BOK Financial Corp. shareholders	618,121	435,030	500,758
Parent Company [Member] | Dividends, interest and fees received from bank susidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Total revenue	483,868	179,140	344,007
Parent Company [Member] | Dividends, interest and fees received from non-bank subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Total revenue	8,030	25,050	9,325
Parent Company [Member] | Other revenue [Member]
Condensed Income Statements, Captions [Line Items]
Total revenue	$ 767	$ 907	$ 1,036