Consolidated Statements of Earnings (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Interest revenue [Abstract]
Loans	$ 125,069	$ 126,248	$ 374,479	$ 384,406
Residential mortgage loans held for sale	2,168	2,310	6,254	5,862
Trading securities	509	555	1,608	1,219
Taxable securities	3,434	4,124	10,836	12,840
Tax-exempt securities	1,163	764	3,341	2,662
Total investment securities	4,597	4,888	14,177	15,502
Taxable securities	50,179	59,482	156,569	180,721
Tax-exempt securities	560	699	1,851	1,931
Total available for sale securities	50,739	60,181	158,420	182,652
Fair value option securities	802	1,886	2,980	7,684
Funds sold and resell agreements	6	3	12	9
Total interest revenue	183,890	196,071	557,930	597,334
Interest expense [Abstract]
Deposits	13,526	15,917	42,316	49,805
Borrowed funds	1,804	1,652	5,134	5,033
Subordinated debentures	2,209	2,475	6,568	11,539
Total interest expense	17,539	20,044	54,018	66,377
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 [Abstract]
Brokerage and trading revenue	32,338	31,261	96,963	94,972
Transaction card revenue	30,055	27,788	87,689	79,976
Trust fees and commissions	23,892	19,654	71,008	58,023
Deposit service charges and fees	24,742	25,148	71,670	74,743
Mortgage banking revenue	23,486	50,266	100,058	122,892
Bank-owned life insurance	2,408	2,707	7,870	8,416
Other revenue	9,852	9,149	30,535	27,273
Total fees and commissions	146,773	165,973	465,793	466,295
Gain (loss) on assets, net	(377)	452	(1,576)	(1,552)
Gain (loss) on derivatives, net	31	464	(3,437)	336
Gain (loss) on fair value option securities, net	(80)	6,192	(12,407)	11,311
Gain on available for sale securities, net	478	7,967	9,086	32,779
Total other-than-temporary impairment losses	(1,436)	0	(2,574)	(640)
Portion of loss recognized in (reclassified from) other comprehensive income	(73)	(1,104)	266	(5,044)
Net impairment losses recognized in earnings	(1,509)	(1,104)	(2,308)	(5,684)
Total other operating revenue	145,316	179,944	455,151	503,485
Other operating expense [Abstract]
Personnel	125,799	122,775	379,563	359,841
Business promotion	5,355	6,054	16,578	17,188
Contribution to BOKF Foundation	2,062	0	2,062	0
Professional fees and services	7,183	7,991	22,549	23,933
Net occupancy and equipment	17,280	16,914	50,670	49,843
Insurance	3,939	3,690	11,728	11,567
Data processing and communications	25,695	26,486	77,879	73,894
Printing, postage and supplies	3,505	3,611	10,759	10,825
Net losses and operating expenses of repossessed assets	2,014	5,706	3,542	13,863
Amortization of intangible assets	835	742	2,586	1,862
Mortgage banking costs	8,753	13,036	24,017	33,792
Change in fair value of mortgage servicing rights	346	9,576	(16,627)	13,899
Other expense	7,878	5,759	23,268	16,980
Total other 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 (loss) 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
Earnings per share: [Abstract]
Basic (in dollars per share)	$ 1.10	$ 1.28	$ 3.55	$ 3.94
Diluted (in dollars per share)	$ 1.10	$ 1.27	$ 3.54	$ 3.92
Average shares used in computation: [Abstract]
Basic (in shares)	68,049,179	67,966,700	67,953,253	67,704,343
Diluted (in shares)	68,272,861	68,334,989	68,175,915	67,981,558
Dividends declared per share (in dollars per share)	$ 0.38	$ 0.38	$ 1.14	$ 1.09