Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Numerator: [Abstract]:
Net income attributable to BOK Financial Corporation	$ 87,964	$ 83,615
Earnings allocated to participating securities	(971)	(740)
Numerator for basic earnings per share - income available to common shareholders	86,993	82,875
Effect of reallocating undistributed earnings of participating securities	5	2
Numerator for diluted earnings per share - income available to common shareholders	$ 86,998	$ 82,877
Denominator: [Abstract]
Weighted Average Number of Shares Outstanding, Basic and Diluted	68,569,475	68,268,458
Less: Participating securities included in weighted average shares outstanding (in shares)	(754,925)	(603,158)
Denominator for basic earnings per common share (in shares)	67,814,550	67,665,300
Dilutive effect of employee stock compensation plans (in shares)	225,630	276,595
Denominator for diluted earnings per common share (in shares)	68,040,180	67,941,895
Basic earnings per share (per share)	$ 1.28	$ 1.22
Diluted earnings per share (per share)	$ 1.28	$ 1.22
Excludes employee stock options with exercise prices greater than current market price.	87,377	356,708