Shareholders' Equity (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Common stock, authorized (in shares)	2,500,000,000		2,500,000,000
Common stock, par value (in dollars per share)	$ 0.00006		$ 0.00006
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 149,920,000		$ 128,979,000		$ 107,839,000
Net change in unrealized gain (loss)	(275,945,000)		66,197,000		47,287,000
Transfer of net unrealized gain from AFS to Investment securities					0
Reclassification adjustments included in earnings [Abstract]
Interest revenue, Investment securities, Taxable securities	(3,210,000)		(6,601,000)		(1,357,000)
Interest expense, Subordinated debentures	262,000		453,000		304,000
Net impairment losses recognized in earnings	2,308,000		7,351,000		23,507,000
Gain on available for sale securities, net	(10,720,000)		(33,845,000)		(34,144,000)
Other comprehensive income (loss) before income taxes	(287,305,000)		33,555,000		35,597,000
Federal and state income tax	111,762,000	[1]	(12,614,000)	[1]	(14,457,000)	[1]
Other comprehensive income (loss), net of income taxes	(175,543,000)		20,941,000		21,140,000
Ending balance	(25,623,000)		149,920,000		128,979,000
Total Capital (to Risk Weighted Assets) [Abstract]
Total Capital Ratio Required to be Well Capitalized	10.00%		10.00%
Total Capital	3,017,022,000		2,877,949,000
Total Capital to Risk Weighted Assets	15.56%		15.13%
Tier I Capital (to Risk Weighted Assets) [Abstract]
Tier I Capital Ratio Required to be Well Capitalized	6.00%		6.00%
Tier I Capital	2,668,981,000		2,430,671,000
Tier I Capital to Risk Weighted Assets	13.77%		12.78%
Tier I Capital (to Average Assets) [Abstract]
Leverage Ratio Required to be Well Capitalized	5.00%		5.00%
Tier I Capital to Average Assets	10.05%		9.01%
Accumulated Net Unrealized Gain (Loss) on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	155,553,000		135,740,000		122,494,000
Net change in unrealized gain (loss)	(284,104,000)		58,921,000		45,593,000
Transfer of net unrealized gain from AFS to Investment securities					(12,999,000)
Reclassification adjustments included in earnings [Abstract]
Interest revenue, Investment securities, Taxable securities	0		0		0
Interest expense, Subordinated debentures	0		0		0
Net impairment losses recognized in earnings	2,308,000		7,351,000		23,507,000
Gain on available for sale securities, net	(10,720,000)		(33,845,000)		(34,144,000)
Other comprehensive income (loss) before income taxes	(292,516,000)		32,427,000		21,957,000
Federal and state income tax	113,788,000	[1]	(12,614,000)	[1]	(8,711,000)	[1]
Other comprehensive income (loss), net of income taxes	(178,728,000)		19,813,000		13,246,000
Ending balance	(23,175,000)		155,553,000		135,740,000
Accumulated Unrealized Gain on Investment Securities Transferred from AFS [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	3,078,000		6,673,000		0
Net change in unrealized gain (loss)	0		0		0
Transfer of net unrealized gain from AFS to Investment securities					12,999,000
Reclassification adjustments included in earnings [Abstract]
Interest revenue, Investment securities, Taxable securities	(3,210,000)		(6,601,000)		(1,357,000)
Interest expense, Subordinated debentures	0		0		0
Net impairment losses recognized in earnings	0		0		0
Gain on available for sale securities, net	0		0		0
Other comprehensive income (loss) before income taxes	(3,210,000)		(6,601,000)		11,642,000
Federal and state income tax	1,250,000	[1]	3,006,000	[1]	(4,969,000)	[1]
Other comprehensive income (loss), net of income taxes	(1,960,000)		(3,595,000)		6,673,000
Ending balance	1,118,000		3,078,000		6,673,000
Accumulated Unrealized Gain (Loss) on Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(8,296,000)		(12,742,000)		(13,777,000)
Net change in unrealized gain (loss)	8,159,000		7,276,000		1,694,000
Transfer of net unrealized gain from AFS to Investment securities					0
Reclassification adjustments included in earnings [Abstract]
Interest revenue, Investment securities, Taxable securities	0		0		0
Interest expense, Subordinated debentures	0		0		0
Net impairment losses recognized in earnings	0		0		0
Gain on available for sale securities, net	0		0		0
Other comprehensive income (loss) before income taxes	8,159,000		7,276,000		1,694,000
Federal and state income tax	(3,174,000)	[1]	(2,830,000)	[1]	(659,000)	[1]
Other comprehensive income (loss), net of income taxes	4,985,000		4,446,000		1,035,000
Ending balance	(3,311,000)		(8,296,000)		(12,742,000)
Accumulated Loss on Effective Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(415,000)		(692,000)		(878,000)
Net change in unrealized gain (loss)	0		0		0
Transfer of net unrealized gain from AFS to Investment securities					0
Reclassification adjustments included in earnings [Abstract]
Interest revenue, Investment securities, Taxable securities	0		0		0
Interest expense, Subordinated debentures	262,000		453,000		304,000
Net impairment losses recognized in earnings	0		0		0
Gain on available for sale securities, net	0		0		0
Other comprehensive income (loss) before income taxes	262,000		453,000		304,000
Federal and state income tax	(102,000)	[1]	(176,000)	[1]	(118,000)	[1]
Other comprehensive income (loss), net of income taxes	160,000		277,000		186,000
Ending balance	(255,000)		(415,000)		(692,000)
BOKF, NA [Member]
Allowed dividends without regulatory approval	225,000,000		275,000,000		270,000,000
Maximum percentage of unimpaired capital on loan commitments and equity investments to a single affiliate (in hundredths)	10.00%
Maximum percentage of unimpaired capital on loan commitments and equity investments to all affiliates (in hundredths)	20.00%
Maximum loan commitments and equity investments to a single affiliate	229,000,000
Maximum loan commitments and equity investments to all affiliates	459,000,000
Largest loan commitment and equity investment to a single affiliate	220,000,000
Aggregate loan commitment and equity investment to all affiliates	334,000,000		330,000,000
Largest amount outstanding to a single affiliate	22,000,000
Outstanding amounts to all affiliates	27,000,000		68,000,000
Total Capital (to Risk Weighted Assets) [Abstract]
Total Capital	2,293,673,000		2,296,451,000
Total Capital to Risk Weighted Assets	11.88%		12.13%
Tier I Capital (to Risk Weighted Assets) [Abstract]
Tier I Capital	1,946,247,000		1,849,769,000
Tier I Capital to Risk Weighted Assets	10.08%		9.77%
Tier I Capital (to Average Assets) [Abstract]
Tier I Capital to Average Assets	7.38%		6.89%
Other Non-Bank Subsidiaries [Member]
Allowed dividends without regulatory approval	158,000,000
Perpetual stock [Member]
Preferred stock, authorized (in shares)	1,000,000,000
Preferred stock at par value (in dollars per share)	$ 0.00005
Preferred stock conversion rate	one share of Common Stock for each 36 shares of Series A Preferred Stock at the option of the holder
Preferred stock, Rate of annual cumulative dividends (in hundredths)	10.00%
Preferred stock, Liquidation preference per share	$ 0.06
Preferred stock, Aggregate liquidation preference	$ 15,000,000
Preferred Stock, Shares Outstanding	0		0		0
Common Stock [Member]
Common stock, authorized (in shares)	2,500,000,000
Common stock, par value (in dollars per share)	$ 0.00006
Common stock, number of vote per share	$ 1

[1] 1 Calculated using 39% effective tax rate.