Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator: [Abstract]:
Net income attributable to BOK Financial Corp. shareholders	$ 232,668	$ 288,565	$ 292,435
Less: Earnings allocated to participating securities	2,883	3,383	3,239
Numerator for basic earnings per share - income available to common shareholders	229,785	285,182	289,196
Effect of reallocating undistributed earnings of participating securities	1	3	4
Numerator for diluted earnings per share - income available to common shareholders	$ 229,786	$ 285,185	$ 289,200
Denominator: [Abstract]
Weighted average shares outstanding	65,901,110	68,397,215	69,159,902
Less: Participating securities included in weighted average shares outstanding (in shares)	815,483	802,526	765,708
Denominator for basic earnings per common share (in shares)	65,085,627	67,594,689	68,394,194
Dilutive effect of employee stock compensation plans (in shares)	58,271	96,969	150,576
Denominator for diluted earnings per common share (in shares)	65,143,898	67,691,658	68,544,770
Basic (in dollars per share)	$ 3.53	$ 4.22	$ 4.23
Diluted earnings per share (per share)	$ 3.53	$ 4.21	$ 4.22
Excludes employee stock options with exercise prices greater than current market price.	0	0	0