Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Net interest revenue from external sources	$ 166,097	$ 168,892	$ 328,739	$ 340,344
Net interest revenue (expense) from internal sources	0	0	0	0
Net interest revenue	166,097	168,892	328,739	340,344
Provision for credit losses	0	0	0	(8,000)
Net interest revenue after provision for credit losses	166,097	168,892	328,739	348,344
Other operating revenue	162,569	163,340	299,575	324,026
Other operating expense	214,707	210,921	399,811	414,904
Net direct contribution	113,959	121,311	228,503	257,466
Corporate expense allocations	0	0	0	0
Net income before taxes	113,959	121,311	228,503	257,466
Federal and state income taxes	37,230	41,423	74,731	88,519
Net income	76,729	79,888	153,772	168,947
Net income (loss) attributable to non-controlling interest	834	(43)	1,287	1,052
Net income attributable to BOK Financial Corporation shareholders	75,895	79,931	152,485	167,895
Average assets	27,486,821	27,659,324	27,363,480	27,586,780
Average invested capital	3,176,724	3,027,654	3,141,097	3,012,828
Performance measurements: [Abstract]
Return on average assets	1.11%	1.16%	1.12%	1.23%
Return on average invested capital	9.58%	10.59%	9.79%	11.24%
Efficiency ratio	63.62%	63.11%	61.74%	62.07%
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	95,018	90,551	186,037	181,433
Net interest revenue (expense) from internal sources	(7,857)	(9,389)	(16,714)	(18,534)
Net interest revenue	87,161	81,162	169,323	162,899
Provision for credit losses	(2,812)	86	(6,043)	1,107
Net interest revenue after provision for credit losses	89,973	81,076	175,366	161,792
Other operating revenue	44,836	43,330	85,525	84,781
Other operating expense	50,922	47,342	100,310	94,002
Net direct contribution	83,887	77,064	160,581	152,571
Corporate expense allocations	18,367	18,080	35,653	36,079
Net income before taxes	65,520	58,984	124,928	116,492
Federal and state income taxes	25,487	22,945	48,597	45,315
Net income	40,033	36,039	76,331	71,177
Net income (loss) attributable to non-controlling interest	0	0	0	0
Net income attributable to BOK Financial Corporation shareholders	40,033	36,039	76,331	71,177
Average assets	11,243,678	10,363,144	11,100,687	10,486,544
Average invested capital	937,085	899,087	934,768	895,748
Performance measurements: [Abstract]
Return on average assets	1.43%	1.39%	1.39%	1.37%
Return on average invested capital	17.14%	16.08%	16.47%	16.02%
Efficiency ratio	38.52%	37.96%	39.07%	37.89%
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	24,170	24,830	48,826	48,925
Net interest revenue (expense) from internal sources	4,666	5,167	8,860	10,650
Net interest revenue	28,836	29,997	57,686	59,575
Provision for credit losses	1,345	1,402	2,201	2,332
Net interest revenue after provision for credit losses	27,491	28,595	55,485	57,243
Other operating revenue	51,256	62,309	94,668	122,108
Other operating expense	49,087	47,151	90,932	92,159
Net direct contribution	29,660	43,753	59,221	87,192
Corporate expense allocations	16,911	14,690	32,750	28,859
Net income before taxes	12,749	29,063	26,471	58,333
Federal and state income taxes	4,959	11,306	10,297	22,692
Net income	7,790	17,757	16,174	35,641
Net income (loss) attributable to non-controlling interest	0	0	0	0
Net income attributable to BOK Financial Corporation shareholders	7,790	17,757	16,174	35,641
Average assets	5,668,256	5,695,096	5,642,181	5,709,446
Average invested capital	276,294	297,674	279,897	297,375
Performance measurements: [Abstract]
Return on average assets	0.55%	1.25%	0.58%	1.26%
Return on average invested capital	11.31%	23.93%	11.65%	24.17%
Efficiency ratio	55.11%	49.26%	53.74%	47.91%
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	5,765	6,512	11,604	12,991
Net interest revenue (expense) from internal sources	4,719	5,107	9,403	10,403
Net interest revenue	10,484	11,619	21,007	23,394
Provision for credit losses	19	931	(26)	1,449
Net interest revenue after provision for credit losses	10,465	10,688	21,033	21,945
Other operating revenue	65,527	55,287	119,787	106,778
Other operating expense	55,156	51,440	104,403	98,562
Net direct contribution	20,836	14,535	36,417	30,161
Corporate expense allocations	12,388	13,019	23,810	25,559
Net income before taxes	8,448	1,516	12,607	4,602
Federal and state income taxes	3,286	590	4,904	1,790
Net income	5,162	926	7,703	2,812
Net income (loss) attributable to non-controlling interest	0	0	0	0
Net income attributable to BOK Financial Corporation shareholders	5,162	926	7,703	2,812
Average assets	4,556,825	4,544,061	4,589,141	4,615,169
Average invested capital	214,936	206,219	208,909	204,161
Performance measurements: [Abstract]
Return on average assets	0.45%	0.08%	0.34%	0.12%
Return on average invested capital	9.63%	1.80%	7.44%	2.78%
Efficiency ratio	72.29%	76.87%	73.72%	75.24%
Corporate, Non-Segment [Member] | Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	41,144	46,999	82,272	96,995
Net interest revenue (expense) from internal sources	(1,528)	(885)	(1,549)	(2,519)
Net interest revenue	39,616	46,114	80,723	94,476
Provision for credit losses	1,448	(2,419)	3,868	(12,888)
Net interest revenue after provision for credit losses	38,168	48,533	76,855	107,364
Other operating revenue	950	2,414	(405)	10,359
Other operating expense	59,542	64,988	104,166	130,181
Net direct contribution	(20,424)	(14,041)	(27,716)	(12,458)
Corporate expense allocations	(47,666)	(45,789)	(92,213)	(90,497)
Net income before taxes	27,242	31,748	64,497	78,039
Federal and state income taxes	3,498	6,582	10,933	18,722
Net income	23,744	25,166	53,564	59,317
Net income (loss) attributable to non-controlling interest	834	(43)	1,287	1,052
Net income attributable to BOK Financial Corporation shareholders	22,910	25,209	52,277	58,265
Average assets	6,018,062	7,057,023	6,031,471	6,775,621
Average invested capital	$ 1,748,409	$ 1,624,674	$ 1,717,523	$ 1,615,544