Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator: [Abstract]
Net income attributable to BOK Financial Corporation shareholders	$ 75,738	$ 87,382	$ 243,633	$ 268,626
Earnings allocated to participating securities	799	278	2,623	1,994
Numerator for basic earnings per share - income available to common shareholders	74,939	87,104	241,010	266,632
Effect of reallocating undistributed earnings of participating securities	2	1	6	6
Numerator for diluted earnings per share - income available to common shareholders	$ 74,941	$ 87,105	$ 241,016	$ 266,638
Denominator: [Abstract]
Weighted average shares outstanding (in shares)	68,770,950	68,183,171	68,687,609	68,204,078
Less: Participating securities included in weighted average shares (in shares)	721,771	216,471	734,356	499,735
Denominator for basic earnings per common share (in shares)	68,049,179	67,966,700	67,953,253	67,704,343
Dilutive effect of employee stock compensation plans (in shares)	223,682	368,289	222,662	277,215
Denominator for diluted earnings per common share (in shares)	68,272,861	68,334,989	68,175,915	67,981,558
Basic earnings per share (per share)	$ 1.10	$ 1.28	$ 3.55	$ 3.94
Diluted earnings per share (per share)	$ 1.10	$ 1.27	$ 3.54	$ 3.92
Excludes employee stock options with exercise prices greater than current market price.	0	87,749	0	270,288