Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Numerator: [Abstract]:
Net income attributable to BOK Financial Corp. shareholders	$ 351,191	$ 285,875	$ 246,754
Earnings allocated to participating securities	(2,541)	(2,214)	(1,583)
Numerator for basic earnings per share - income available to common shareholders	348,650	283,661	245,171
Effect of reallocating undistributed earnings of participating securities	6	6	3
Numerator for diluted earnings per share - income available to common shareholders	$ 348,656	$ 283,667	$ 245,174
Denominator: [Abstract]
Weighted average shares outstanding	68,221,013	68,313,898	68,062,047
Less: Participating securities included in weighted average shares outstanding (in shares)	(536,970)	(526,222)	(434,312)
Denominator for basic earnings per common share (in shares)	67,684,043	67,787,676	67,627,735
Dilutive effect of employee stock compensation plans (in shares)	280,897	251,087	203,999
Denominator for diluted earnings per common share (in shares)	67,964,940	68,038,763	67,831,734
Basic earnings per share (per share)	$ 5.15	$ 4.18	$ 3.63
Diluted earnings per share (per share)	$ 5.13	$ 4.17	$ 3.61
Excludes employee stock options with exercise prices greater than current market price.	224,653	769,041	1,245,483