Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Net interest revenue from external sources	$ 162,642	$ 171,452
Net interest revenue (expense) from internal sources	0	0
Net interest revenue	162,642	171,452
Provision for credit losses	0	(8,000)
Net interest revenue after provision for credit losses	162,642	179,452
Other operating revenue	137,006	160,685
Other operating expense	185,104	203,982
Net direct contribution	114,544	136,155
Corporate expense allocations	0	0
Net income before taxes	114,544	136,155
Federal and state income taxes	37,501	47,096
Net income	77,043	89,059
Net income attributable to non-controlling interest	453	1,095
Net income attributable to BOK Financial Corporation shareholders	76,590	87,964
Average assets	27,238,768	27,513,431
Average invested capital	3,105,074	2,997,839
Performance measurements: [Abstract]
Return on average assets	1.14%	1.30%
Return on average invested capital	10.00%	11.90%
Efficiency ratio	59.69%	61.04%
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	91,009	90,882
Net interest revenue (expense) from internal sources	(8,857)	(9,145)
Net interest revenue	82,152	81,737
Provision for credit losses	(3,312)	1,021
Net interest revenue after provision for credit losses	85,464	80,716
Other operating revenue	40,689	41,451
Other operating expense	49,389	46,661
Net direct contribution	76,764	75,506
Corporate expense allocations	17,285	17,999
Net income before taxes	59,479	57,507
Federal and state income taxes	23,137	22,370
Net income	36,342	35,137
Net income attributable to non-controlling interest	0	0
Net income attributable to BOK Financial Corporation shareholders	36,342	35,137
Average assets	10,956,107	10,629,342
Average invested capital	934,328	890,844
Performance measurements: [Abstract]
Return on average assets	1.35%	1.34%
Return on average invested capital	15.77%	16.00%
Efficiency ratio	39.67%	37.82%
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	24,657	24,095
Net interest revenue (expense) from internal sources	4,193	5,483
Net interest revenue	28,850	29,578
Provision for credit losses	861	930
Net interest revenue after provision for credit losses	27,989	28,648
Other operating revenue	43,411	59,799
Other operating expense	41,844	45,008
Net direct contribution	29,556	43,439
Corporate expense allocations	15,839	14,169
Net income before taxes	13,717	29,270
Federal and state income taxes	5,336	11,386
Net income	8,381	17,884
Net income attributable to non-controlling interest	0	0
Net income attributable to BOK Financial Corporation shareholders	8,381	17,884
Average assets	5,615,816	5,723,956
Average invested capital	285,086	297,073
Performance measurements: [Abstract]
Return on average assets	0.61%	1.27%
Return on average invested capital	11.92%	24.41%
Efficiency ratio	52.22%	46.58%
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	5,828	6,480
Net interest revenue (expense) from internal sources	4,683	5,295
Net interest revenue	10,511	11,775
Provision for credit losses	49	519
Net interest revenue after provision for credit losses	10,462	11,256
Other operating revenue	54,261	51,490
Other operating expense	49,248	47,122
Net direct contribution	15,475	15,624
Corporate expense allocations	11,422	12,540
Net income before taxes	4,053	3,084
Federal and state income taxes	1,577	1,200
Net income	2,476	1,884
Net income attributable to non-controlling interest	0	0
Net income attributable to BOK Financial Corporation shareholders	2,476	1,884
Average assets	4,621,817	4,687,067
Average invested capital	202,191	202,313
Performance measurements: [Abstract]
Return on average assets	0.22%	0.16%
Return on average invested capital	4.97%	3.78%
Efficiency ratio	75.42%	73.55%
Corporate, Non-Segment [Member] | Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	41,148	49,995
Net interest revenue (expense) from internal sources	(19)	(1,633)
Net interest revenue	41,129	48,362
Provision for credit losses	2,402	(10,470)
Net interest revenue after provision for credit losses	38,727	58,832
Other operating revenue	(1,355)	7,945
Other operating expense	44,623	65,191
Net direct contribution	(7,251)	1,586
Corporate expense allocations	(44,546)	(44,708)
Net income before taxes	37,295	46,294
Federal and state income taxes	7,451	12,140
Net income	29,844	34,154
Net income attributable to non-controlling interest	453	1,095
Net income attributable to BOK Financial Corporation shareholders	29,391	33,059
Average assets	6,045,028	6,473,066
Average invested capital	$ 1,683,469	$ 1,607,609