Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Net interest revenue from external sources	$ 674,477	$ 707,549	$ 693,045
Net interest revenue (expense) from internal sources	0	0	0
Net interest revenue	674,477	707,549	693,045
Provision for credit losses	(27,900)	(22,000)	(6,050)
Net interest revenue after provision for credit losses	702,377	729,549	699,095
Other operating revenue	614,472	653,678	528,538
Operating expense	840,620	840,363	779,298
Income before taxes	476,229	542,864	448,335
Federal and state income tax	157,298	188,740	158,511
Net income	318,931	354,124	289,824
Net income attributable to non-controlling interests	2,322	2,933	3,949
Net income attributable to BOK Financial Corp. shareholders	316,609	351,191	285,875
Average assets	27,381,094	26,289,150	24,494,861
Average invested capital	3,011,082	2,905,955	2,681,865
Performance measurements: [Abstract]
Return on average assets	1.16%	1.34%	1.17%
Return on average invested capital	10.51%	12.09%	10.66%
Efficiency ratio	65.03%	62.87%	63.83%
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	364,604	367,533	342,853
Net interest revenue (expense) from internal sources	(37,025)	(43,438)	(30,689)
Net interest revenue	327,579	324,095	312,164
Provision for credit losses	(3,468)	10,852	20,760
Net interest revenue after provision for credit losses	331,047	313,243	291,404
Other operating revenue	171,900	171,131	147,545
Operating expense	244,211	246,954	230,458
Income before taxes	258,736	237,420	208,491
Federal and state income tax	100,648	92,356	81,103
Net income	158,088	145,064	127,388
Net income attributable to non-controlling interests	0	0	0
Net income attributable to BOK Financial Corp. shareholders	158,088	145,064	127,388
Average assets	10,483,706	10,147,805	9,383,530
Average invested capital	906,716	882,037	884,171
Performance measurements: [Abstract]
Return on average assets	1.51%	1.43%	1.36%
Return on average invested capital	17.44%	16.45%	14.41%
Efficiency ratio	49.18%	51.36%	50.22%
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	99,509	101,029	102,854
Net interest revenue (expense) from internal sources	20,290	21,305	27,416
Net interest revenue	119,799	122,334	130,270
Provision for credit losses	4,628	9,198	13,598
Net interest revenue after provision for credit losses	115,171	113,136	116,672
Other operating revenue	216,828	262,908	182,875
Operating expense	226,852	248,767	239,302
Income before taxes	105,147	127,277	60,245
Federal and state income tax	40,902	49,511	23,435
Net income	64,245	77,766	36,810
Net income attributable to non-controlling interests	0	0	0
Net income attributable to BOK Financial Corp. shareholders	64,245	77,766	36,810
Average assets	5,669,580	5,726,564	5,937,584
Average invested capital	293,736	289,665	273,905
Performance measurements: [Abstract]
Return on average assets	1.13%	1.36%	0.62%
Return on average invested capital	21.87%	26.85%	13.44%
Efficiency ratio	66.62%	63.97%	73.06%
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	25,478	27,647	30,859
Net interest revenue (expense) from internal sources	20,061	21,456	16,540
Net interest revenue	45,539	49,103	47,399
Provision for credit losses	1,275	2,284	2,960
Net interest revenue after provision for credit losses	44,264	46,819	44,439
Other operating revenue	213,790	200,007	171,827
Operating expense	237,540	214,293	190,702
Income before taxes	20,514	32,533	25,564
Federal and state income tax	7,980	12,655	9,944
Net income	12,534	19,878	15,620
Net income attributable to non-controlling interests	0	0	0
Net income attributable to BOK Financial Corp. shareholders	12,534	19,878	15,620
Average assets	4,556,132	4,357,641	4,073,623
Average invested capital	203,914	184,707	174,877
Performance measurements: [Abstract]
Return on average assets	0.28%	0.46%	0.38%
Return on average invested capital	6.15%	10.76%	8.93%
Efficiency ratio	91.92%	86.23%	87.21%
Corporate, Non-Segment [Member] | Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	184,886	211,340	216,479
Net interest revenue (expense) from internal sources	(3,326)	677	(13,267)
Net interest revenue	181,560	212,017	203,212
Provision for credit losses	(30,335)	(44,334)	(43,368)
Net interest revenue after provision for credit losses	211,895	256,351	246,580
Other operating revenue	11,954	19,632	26,291
Operating expense	132,017	130,349	118,836
Income before taxes	91,832	145,634	154,035
Federal and state income tax	7,768	34,218	44,029
Net income	84,064	111,416	110,006
Net income attributable to non-controlling interests	2,322	2,933	3,949
Net income attributable to BOK Financial Corp. shareholders	81,742	108,483	106,057
Average assets	6,671,676	6,057,140	5,100,124
Average invested capital	$ 1,606,716	$ 1,549,546	$ 1,348,912