Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest revenue	$ 174,001	$ 182,113	$ 344,640	$ 364,687
Provision for credit losses	2,700	36,040	8,950	78,140
Decrease in fair value of mortgage service rights	(13,493)	(19,458)	(10,364)	(5,526)
Income before taxes	111,052	97,600	214,570	188,225
Federal and state income tax	39,357	32,042	78,109	62,325
Net income	71,695	65,558	136,461	125,900
Net income attributable to non-controlling interest	2,688	2,036	2,680	2,245
Net income attributable to BOK Financial Corporation	69,007	63,522	133,781	123,655
Commercial [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest revenue from external sources	86,067	85,129	170,020	170,027
Net interest revenue (expense) from internal sources	(7,225)	(12,633)	(16,270)	(25,016)
Net interest revenue	78,842	72,496	153,750	145,011
Other operating revenue	36,104	33,531	71,610	63,213
Operating expense	54,594	50,578	107,112	100,401
Provision for credit losses	4,660	22,477	11,437	50,856
Decrease in fair value of mortgage service rights	0	0	0	0
Gain on financial instruments, net	0	0	0	0
Loss on repossessed assets, net	(3,147)	(10,741)	(6,731)	(15,764)
Income before taxes	52,545	22,231	100,080	41,203
Federal and state income tax	20,440	8,648	38,931	16,028
Net income	32,105	13,583	61,149	25,175
Net income attributable to non-controlling interest	0	0	0	0
Net income attributable to BOK Financial Corporation	32,105	13,583	61,149	25,175
Average assets	9,393,935	8,982,359	9,283,264	9,078,390
Average invested capital	867,491	909,930	865,439	920,056
Performance measurements: [Abstract]
Return on average assets	1.37%	0.61%	1.33%	0.56%
Return on average invested capital	14.84%	5.99%	14.25%	5.52%
Efficiency ratio	47.50%	47.70%	47.53%	48.22%
Consumer [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest revenue from external sources	21,357	21,498	40,022	40,993
Net interest revenue (expense) from internal sources	7,597	11,444	16,655	23,323
Net interest revenue	28,954	32,942	56,677	64,316
Other operating revenue	46,340	50,439	89,760	93,661
Operating expense	58,130	61,613	113,269	117,782
Provision for credit losses	3,435	10,300	7,035	14,008
Decrease in fair value of mortgage service rights	(13,493)	(19,458)	(10,364)	(5,526)
Gain on financial instruments, net	11,145	22,431	5,208	22,220
Loss on repossessed assets, net	(229)	90	(421)	121
Income before taxes	11,152	14,531	20,556	43,002
Federal and state income tax	4,338	5,653	7,996	16,728
Net income	6,814	8,878	12,560	26,274
Net income attributable to non-controlling interest	0	0	0	0
Net income attributable to BOK Financial Corporation	6,814	8,878	12,560	26,274
Average assets	5,819,151	6,197,861	5,940,101	6,178,632
Average invested capital	271,353	312,192	272,301	290,796
Performance measurements: [Abstract]
Return on average assets	0.47%	0.57%	0.43%	0.86%
Return on average invested capital	10.07%	11.41%	9.30%	18.22%
Efficiency ratio	77.20%	73.89%	77.35%	74.56%
Wealth Management [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest revenue from external sources	7,184	8,358	14,713	16,987
Net interest revenue (expense) from internal sources	3,476	2,391	6,219	5,412
Net interest revenue	10,660	10,749	20,932	22,399
Other operating revenue	42,699	42,020	82,558	79,340
Operating expense	46,899	43,829	90,086	84,901
Provision for credit losses	836	3,135	1,280	5,900
Decrease in fair value of mortgage service rights	0	0	0	0
Gain on financial instruments, net	0	15	18	16
Loss on repossessed assets, net	0	0	0	0
Income before taxes	5,624	5,820	12,142	10,954
Federal and state income tax	2,188	2,264	4,723	4,261
Net income	3,436	3,556	7,419	6,693
Net income attributable to non-controlling interest	0	0	0	0
Net income attributable to BOK Financial Corporation	3,436	3,556	7,419	6,693
Average assets	3,659,617	3,355,079	3,643,497	3,321,811
Average invested capital	176,069	167,903	175,505	167,495
Performance measurements: [Abstract]
Return on average assets	0.38%	0.43%	0.41%	0.41%
Return on average invested capital	7.83%	8.49%	8.52%	8.06%
Efficiency ratio	87.89%	83.06%	87.05%	83.45%
Tax Equivalent Adjustment [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest revenue from external sources	2,261	2,327	4,582	4,743
Net interest revenue (expense) from internal sources	0	0	0	0
Net interest revenue	2,261	2,327	4,582	4,743
Other operating revenue	0	0	0	0
Operating expense	0	0	0	0
Provision for credit losses	0	0	0	0
Decrease in fair value of mortgage service rights	0	0	0	0
Gain on financial instruments, net	0	0	0	0
Loss on repossessed assets, net	0	0	0	0
Income before taxes	2,261	2,327	4,582	4,743
Federal and state income tax	0	0	0	0
Net income	2,261	2,327	4,582	4,743
Net income attributable to non-controlling interest	0	0	0	0
Net income attributable to BOK Financial Corporation	2,261	2,327	4,582	4,743
Average assets	0	0	0	0
Average invested capital	0	0	0	0
Funds Management and Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest revenue from external sources	57,132	64,801	115,303	131,937
Net interest revenue (expense) from internal sources	(3,848)	(1,202)	(6,604)	(3,719)
Net interest revenue	53,284	63,599	108,699	128,218
Other operating revenue	6,027	3,723	10,448	7,424
Operating expense	26,695	19,790	53,098	45,391
Provision for credit losses	(6,231)	128	(10,802)	7,376
Decrease in fair value of mortgage service rights	0	0	0	0
Gain on financial instruments, net	645	5,280	936	5,448
Loss on repossessed assets, net	(22)	7	(577)	0
Income before taxes	39,470	52,691	77,210	88,323
Federal and state income tax	12,391	15,477	26,459	25,308
Net income	27,079	37,214	50,751	63,015
Net income attributable to non-controlling interest	2,688	2,036	2,680	2,245
Net income attributable to BOK Financial Corporation	24,391	35,178	48,071	60,770
Average assets	5,106,532	4,909,508	4,982,749	4,821,760
Average invested capital	1,335,976	988,704	1,294,836	960,552
BOK Financial Consolidated [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest revenue from external sources	174,001	182,113	344,640	364,687
Net interest revenue (expense) from internal sources	0	0	0	0
Net interest revenue	174,001	182,113	344,640	364,687
Other operating revenue	131,170	129,713	254,376	243,638
Operating expense	186,318	175,810	363,565	348,475
Provision for credit losses	2,700	36,040	8,950	78,140
Decrease in fair value of mortgage service rights	(13,493)	(19,458)	(10,364)	(5,526)
Gain on financial instruments, net	11,790	27,726	6,162	27,684
Loss on repossessed assets, net	(3,398)	(10,644)	(7,729)	(15,643)
Income before taxes	111,052	97,600	214,570	188,225
Federal and state income tax	39,357	32,042	78,109	62,325
Net income	71,695	65,558	136,461	125,900
Net income attributable to non-controlling interest	2,688	2,036	2,680	2,245
Net income attributable to BOK Financial Corporation	69,007	63,522	133,781	123,655
Average assets	23,979,235	23,444,807	23,849,611	23,400,593
Average invested capital	$ 2,650,889	$ 2,378,729	$ 2,608,081	$ 2,338,899
Performance measurements: [Abstract]
Return on average assets	1.15%	1.09%	1.13%	1.07%
Return on average invested capital	10.44%	10.71%	10.34%	10.66%
Efficiency ratio	62.23%	59.56%	60.69%	57.28%