Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator: [Abstract]
Net income attributable to BOK Financial Corporation shareholders	$ 75,632	$ 75,738	$ 228,117	$ 243,633
Less: Earnings allocated to participating securities	898	799	2,479	2,623
Numerator for basic earnings per share - income available to common shareholders	74,734	74,939	225,638	241,010
Effect of reallocating undistributed earnings of participating securities	1	2	3	6
Numerator for diluted earnings per share - income available to common shareholders	$ 74,735	$ 74,941	$ 225,641	$ 241,016
Denominator: [Abstract]
Weighted average shares outstanding (in shares)	69,275,121	68,770,950	69,113,914	68,687,609
Less: Participating securities included in weighted average shares (in shares)	819,255	721,771	749,365	734,356
Denominator for basic earnings per common share (in shares)	68,455,866	68,049,179	68,364,549	67,953,253
Dilutive effect of employee stock compensation plans (in shares)	153,899	223,682	156,042	222,662
Denominator for diluted earnings per common share (in shares)	68,609,765	68,272,861	68,520,591	68,175,915
Basic earnings per share (per share)	$ 1.09	$ 1.10	$ 3.30	$ 3.55
Diluted earnings per share (per share)	$ 1.09	$ 1.10	$ 3.29	$ 3.54
Excludes employee stock options with exercise prices greater than current market price.	0	0	0	0