Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 500,685		$ 446,424		$ 335,685
Other comprehensive income (loss), before income taxes: [Abstract]
Net change in unrealized gain (loss)	241,047		(48,010)		(26,152)
Reclassification adjustments included in earnings: [Abstract]
Loss (gain) on available for sale securities, net	(5,597)		2,801		(4,428)
Other comprehensive gain (loss), before income taxes	235,450		(45,209)		(30,580)
Federal and state income taxes	57,942	[1]	(11,507)	[1]	(11,923)	[2]
Other comprehensive gain (loss), net of income taxes	177,508		(33,702)		(18,657)
Comprehensive income	678,193		412,722		317,028
Comprehensive income (loss) attributable to non-controlling interests	(73)		778		1,041
Comprehensive income attributable to BOK Financial Corp. shareholders	$ 678,266		$ 411,944		$ 315,987

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

[2] Calculated using a 39 percent blended federal and state statutory tax rate.