Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Net interest revenue from external sources	$ 166,351	$ 176,027	$ 503,912	$ 530,957
Net interest revenue (expense) from internal sources	0	0	0	0
Net interest revenue	166,351	176,027	503,912	530,957
Provision for credit losses	(8,500)	0	(16,500)	(8,000)
Net interest revenue after provision for credit losses	174,851	176,027	520,412	538,957
Other operating revenue	145,316	179,944	455,151	503,485
Operating expense	210,644	222,340	608,574	627,487
Net income before taxes	109,523	133,631	366,989	414,955
Federal and state income taxes	33,461	45,778	121,980	144,447
Net income	76,062	87,853	245,009	270,508
Net income attributable to non-controlling interest	324	471	1,376	1,882
Net income attributable to BOK Financial Corporation shareholders	75,738	87,382	243,633	268,626
Average assets	27,254,732	26,588,172	27,474,882	25,883,670
Average invested capital	2,964,923	2,947,192	2,996,685	2,883,952
Performance measurements: [Abstract]
Return on average assets	1.10%	1.31%	1.19%	1.39%
Return on average invested capital	10.13%	11.80%	10.87%	12.44%
Efficiency ratio	66.03%	61.18%	63.35%	60.68%
Operating Segments [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	91,540	91,381	272,889	274,423
Net interest revenue (expense) from internal sources	(9,405)	(11,002)	(27,907)	(34,491)
Net interest revenue	82,135	80,379	244,982	239,932
Provision for credit losses	(1,326)	3,253	(219)	10,393
Net interest revenue after provision for credit losses	83,461	77,126	245,201	229,539
Other operating revenue	42,509	40,091	127,352	131,042
Operating expense	60,969	62,633	179,795	181,119
Net income before taxes	65,001	54,584	192,758	179,462
Federal and state income taxes	25,285	21,233	74,983	69,811
Net income	39,716	33,351	117,775	109,651
Net income attributable to non-controlling interest			0	0
Net income attributable to BOK Financial Corporation shareholders	39,716	33,351	117,775	109,651
Average assets	10,460,986	10,065,208	10,470,800	9,981,793
Average invested capital	911,229	865,157	900,789	880,777
Performance measurements: [Abstract]
Return on average assets	1.51%	1.32%	1.50%	1.47%
Return on average invested capital	17.29%	15.34%	17.48%	16.63%
Efficiency ratio	48.92%	51.99%	48.30%	50.80%
Operating Segments [Member] | Consumer [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	25,131	24,862	74,056	77,173
Net interest revenue (expense) from internal sources	5,060	5,410	15,711	15,093
Net interest revenue	30,191	30,272	89,767	92,266
Provision for credit losses	1,331	338	3,663	5,991
Net interest revenue after provision for credit losses	28,860	29,934	86,104	86,275
Other operating revenue	46,932	80,640	152,066	205,400
Operating expense	56,431	74,486	152,122	197,399
Net income before taxes	19,361	36,088	86,048	94,276
Federal and state income taxes	7,531	14,038	33,473	36,673
Net income	11,830	22,050	52,575	57,603
Net income attributable to non-controlling interest			0	0
Net income attributable to BOK Financial Corporation shareholders	11,830	22,050	52,575	57,603
Average assets	5,655,914	5,671,356	5,691,406	5,705,411
Average invested capital	293,716	292,280	295,394	287,888
Performance measurements: [Abstract]
Return on average assets	0.83%	1.55%	1.24%	1.35%
Return on average invested capital	15.98%	30.01%	23.80%	26.73%
Efficiency ratio	71.53%	61.11%	64.28%	63.62%
Operating Segments [Member] | Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	6,300	7,064	19,373	21,340
Net interest revenue (expense) from internal sources	4,837	5,452	15,209	15,503
Net interest revenue	11,137	12,516	34,582	36,843
Provision for credit losses	255	509	1,704	1,680
Net interest revenue after provision for credit losses	10,882	12,007	32,878	35,163
Other operating revenue	55,601	50,156	163,368	148,105
Operating expense	59,993	53,917	178,694	158,505
Net income before taxes	6,490	8,246	17,552	24,763
Federal and state income taxes	2,525	3,208	6,828	9,633
Net income	3,965	5,038	10,724	15,130
Net income attributable to non-controlling interest			0	0
Net income attributable to BOK Financial Corporation shareholders	3,965	5,038	10,724	15,130
Average assets	4,385,941	4,273,386	4,537,922	4,202,977
Average invested capital	206,872	188,755	204,592	179,772
Performance measurements: [Abstract]
Return on average assets	0.36%	0.47%	0.32%	0.48%
Return on average invested capital	7.62%	10.59%	7.00%	11.25%
Efficiency ratio	89.99%	86.27%	90.57%	85.91%
Corporate, Non-Segment [Member] | Funds Management and Other [Member]
Segment Reporting Information [Line Items]
Net interest revenue from external sources	43,380	52,720	137,594	158,021
Net interest revenue (expense) from internal sources	(492)	140	(3,013)	3,895
Net interest revenue	42,888	52,860	134,581	161,916
Provision for credit losses	(8,760)	(4,100)	(21,648)	(26,064)
Net interest revenue after provision for credit losses	51,648	56,960	156,229	187,980
Other operating revenue	274	9,057	12,365	18,938
Operating expense	33,251	31,304	97,963	90,464
Net income before taxes	18,671	34,713	70,631	116,454
Federal and state income taxes	(1,880)	7,299	6,696	28,330
Net income	20,551	27,414	63,935	88,124
Net income attributable to non-controlling interest	324	471	1,376	1,882
Net income attributable to BOK Financial Corporation shareholders	20,227	26,943	62,559	86,242
Average assets	6,751,891	6,578,222	6,774,754	5,993,489
Average invested capital	$ 1,553,106	$ 1,601,000	$ 1,595,910	$ 1,535,515