Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018		Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 105,347		$ 88,664
Other comprehensive income (loss) before income taxes:
Net change in unrealized gain (loss)	(97,406)		11,411
Reclassification adjustments included in earnings:
Loss (gain) on available for sale securities, net	290		(2,049)
Other comprehensive income (loss) before income taxes	(97,116)		9,362
Federal and state income taxes	(24,808)	[1]	3,616	[2]
Other comprehensive income (loss), net of income taxes	(72,308)		5,746
Comprehensive income	33,039		94,410
Comprehensive income (loss) attributable to non-controlling interests	(215)		308
Comprehensive income attributable to BOK Financial Corp. shareholders	$ 33,254		$ 94,102

[1] Calculated using a 25 percent effective tax rate.

[2] Calculated using a 39 percent effective tax rate.