Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 446,424		$ 335,685		$ 232,281
Other comprehensive income (loss), before income taxes: [Abstract]
Net change in unrealized gain (loss)	(48,010)		(26,152)		(41,521)
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities	0		0		(112)
Loss (gain) on available for sale securities, net	2,801		(4,428)		(11,675)
Other comprehensive loss, before income taxes	(45,209)		(30,580)		(53,308)
Federal and state income taxes	(11,507)	[1]	(11,923)	[2]	(20,754)	[2]
Other comprehensive loss, net of income taxes	(33,702)		(18,657)		(32,554)
Comprehensive income	412,722		317,028		199,727
Comprehensive income (loss) attributable to non-controlling interests	778		1,041		(387)
Comprehensive income attributable to BOK Financial Corp. shareholders	$ 411,944		$ 315,987		$ 200,114

[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.