Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator: [Abstract]:
Net income attributable to BOK Financial Corp. shareholders	$ 288,565	$ 292,435	$ 316,609
Less: Earnings allocated to participating securities	3,383	3,239	3,388
Numerator for basic earnings per share - income available to common shareholders	285,182	289,196	313,221
Effect of reallocating undistributed earnings of participating securities	3	4	7
Numerator for diluted earnings per share - income available to common shareholders	$ 285,185	$ 289,200	$ 313,228
Denominator: [Abstract]
Weighted average shares outstanding	68,397,215	69,159,902	68,719,069
Less: Participating securities included in weighted average shares outstanding (in shares)	802,526	765,708	730,172
Denominator for basic earnings per common share (in shares)	67,594,689	68,394,194	67,988,897
Dilutive effect of employee stock compensation plans (in shares)	96,969	150,576	216,622
Denominator for diluted earnings per common share (in shares)	67,691,658	68,544,770	68,205,519
Basic (in dollars per share)	$ 4.22	$ 4.23	$ 4.61
Diluted earnings per share (per share)	$ 4.21	$ 4.22	$ 4.59
Excludes employee stock options with exercise prices greater than current market price.	0	0	0