Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 295,479		$ 318,931		$ 354,124
Other comprehensive income (loss), before income taxes: [Abstract]
Net change in unrealized gain (loss)	136,775		(275,945)		66,197
Reclassification adjustments included in earnings: [Abstract]
Interest revenue, Investment securities, Taxable securities	(1,216)		(3,210)		(6,601)
Interest expense, Subordinated debentures	296		262		453
Net impairment losses recognized in earnings	373		2,308		7,351
Gain on available for sale securities, net	(1,539)		(10,720)		(33,845)
Other comprehensive income (loss), before income taxes	134,689		(287,305)		33,555
Federal and state income taxes	(52,393)	[1]	111,762	[1]	(12,614)	[1]
Other comprehensive income (loss), net of income taxes	82,296		(175,543)		20,941
Comprehensive income	377,775		143,388		375,065
Comprehensive income attributable to non-controlling interests	3,044		2,322		2,933
Comprehensive income attributable to BOK Financial Corp. shareholders	$ 374,731		$ 141,066		$ 372,132

[1] 1 Calculated using 39% effective tax rate.