Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 154,092	$ 141,858	$ 280,362		$ 389,903
Other Comprehensive Income (Loss), before Tax [Abstract]
Net change in unrealized gain (loss)	(6,783)	46,285	347,985		274,441
Reclassification Adjustments Included in Earnings [Abstract]
Loss (gain) on available for sale securities, net	12	(5)	(5,571)		(1,110)
Other comprehensive income (loss) before income taxes	(6,771)	46,280	342,414		273,331
Federal and state income taxes	(1,625)	11,096	82,167	[1]	66,993	[1]
Other comprehensive income (loss), net of income taxes	(5,146)	35,184	260,247		206,338
Comprehensive income	148,946	177,042	540,609		596,241
Comprehensive income (loss) attributable to non-controlling interests	58	(373)	(444)		(503)
Comprehensive income attributable to BOK Financial Corp. shareholders	$ 148,888	$ 177,415	$ 541,053		$ 596,744

[1] Calculated using a 25 percent blended federal and state statutory tax rate.