Consolidated Statements of Earnings (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest revenue [Abstract]
Loans	$ 126,559	$ 125,069	$ 374,523	$ 374,479
Residential mortgage loans held for sale	2,929	2,168	7,042	6,254
Trading securities	414	509	1,233	1,608
Taxable securities	3,238	3,434	9,715	10,836
Tax-exempt securities	1,373	1,163	4,348	3,341
Total investment securities	4,611	4,597	14,063	14,177
Taxable securities	45,257	50,167	138,970	156,534
Tax-exempt securities	451	560	1,576	1,851
Total available for sale securities	45,708	50,727	140,546	158,385
Fair value option securities	913	814	2,558	3,015
Restricted equity securities	2,133	1,189	4,405	3,516
Interest-bearing cash and cash equivalents	601	355	1,249	817
Total interest revenue	183,868	185,428	545,619	562,251
Interest expense [Abstract]
Deposits	12,719	13,526	38,482	42,316
Borrowed funds	2,204	1,804	5,106	5,134
Subordinated debentures	2,154	2,209	6,501	6,568
Total interest expense	17,077	17,539	50,089	54,018
Net interest revenue	166,791	167,889	495,530	508,233
Provision for credit losses	0	(8,500)	0	(16,500)
Net interest revenue after provision for credit losses	166,791	176,389	495,530	524,733
Other operating revenue [Abstract]
Brokerage and trading revenue	35,263	32,338	103,835	96,963
Transaction card revenue	31,578	30,055	92,222	87,689
Fiduciary and asset management revenue	29,738	23,892	85,003	71,008
Deposit service charges and fees	22,508	24,742	68,330	71,670
Mortgage banking revenue	26,814	23,486	78,988	100,058
Bank-owned life insurance	2,326	2,408	6,706	7,870
Other revenue	10,320	8,314	28,380	26,214
Total fees and commissions	158,547	145,235	463,464	461,472
Loss on other assets, net	(501)	(377)	(4,817)	(1,576)
Gain (loss) on derivatives, net	(93)	31	1,706	(3,437)
Gain (loss) on fair value option securities, net	(332)	(80)	6,504	(12,407)
Change in fair value of mortgage servicing rights	5,281	(346)	(5,624)	16,627
Gain on available for sale securities, net	146	478	1,390	9,086
Total other-than-temporary impairment losses	0	(1,436)	0	(2,574)
Portion of loss recognized in (reclassified from) other comprehensive income	0	(73)	0	266
Net impairment losses recognized in earnings	0	(1,509)	0	(2,308)
Total other operating revenue	163,048	143,432	462,623	467,457
Other operating expense [Abstract]
Personnel	123,043	125,799	351,190	379,563
Business promotion	6,160	5,355	19,151	16,578
Charitable contributions to BOKF Foundation	0	2,062	2,420	2,062
Professional fees and services	14,763	7,183	33,382	22,549
Net occupancy and equipment	18,892	17,280	54,577	50,670
Insurance	4,793	3,939	13,801	11,728
Data processing and communications	29,971	25,695	86,177	77,879
Printing, postage and supplies	3,380	3,505	10,350	10,759
Net losses and operating expenses of repossessed assets	4,966	2,014	7,516	3,542
Amortization of intangible assets	1,100	835	2,865	2,586
Mortgage banking costs	7,734	8,753	19,328	24,017
Other expense	7,032	7,878	20,888	23,268
Total other operating expense	221,834	210,298	621,645	625,201
Net income before taxes	108,005	109,523	336,508	366,989
Federal and state income taxes	31,879	33,461	106,610	121,980
Net income	76,126	76,062	229,898	245,009
Net income attributable to non-controlling interest	494	324	1,781	1,376
Net income attributable to BOK Financial Corporation shareholders	$ 75,632	$ 75,738	$ 228,117	$ 243,633
Earnings per share: [Abstract]
Basic (in dollars per share)	$ 1.09	$ 1.10	$ 3.30	$ 3.55
Diluted (in dollars per share)	$ 1.09	$ 1.10	$ 3.29	$ 3.54
Average shares used in computation: [Abstract]
Basic (in shares)	68,455,866	68,049,179	68,364,549	67,953,253
Diluted (in shares)	68,609,765	68,272,861	68,520,591	68,175,915
Dividends declared per share (in dollars per share)	$ 0.40	$ 0.38	$ 1.20	$ 1.14