Consolidated Statements of Earnings (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest revenue [Abstract]
Loans	$ 146,840	$ 132,985	$ 427,512	$ 392,878
Residential mortgage loans held for sale	3,615	3,793	9,823	10,634
Trading securities	2,996	669	4,136	1,618
Taxable securities	3,000	3,211	9,244	9,788
Tax-exempt securities	1,132	1,274	3,492	3,933
Total investment securities	4,132	4,485	12,736	13,721
Taxable securities	42,513	43,473	130,790	128,933
Tax-exempt securities	529	535	1,591	1,718
Total available for sale securities	43,042	44,008	132,381	130,651
Fair value option securities	1,531	2,480	6,182	6,803
Restricted equity securities	4,510	3,802	12,684	9,627
Interest-bearing cash and cash equivalents	2,651	1,442	7,926	4,114
Total interest revenue	209,317	193,664	613,380	570,046
Interest expense [Abstract]
Deposits	9,812	10,731	30,351	34,102
Borrowed funds	9,191	3,701	25,943	9,395
Subordinated debentures	2,468	596	4,056	4,456
Total interest expense	21,471	15,028	60,350	47,953
Net interest revenue	187,846	178,636	553,030	522,093
Provision for credit losses	10,000	7,500	65,000	11,500
Net interest revenue after provision for credit losses	177,846	171,136	488,030	510,593
Other operating revenue [Abstract]
Brokerage and trading revenue	38,006	31,582	109,877	99,301
Transaction card revenue	33,933	32,514	101,237	96,302
Fiduciary and asset management revenue	34,073	30,807	100,942	94,988
Deposit service charges and fees	23,668	23,606	68,828	67,618
Mortgage banking revenue	42,548	33,170	115,202	109,336
Other revenue	13,080	12,978	38,336	35,650
Total fees and commissions	185,308	164,657	534,422	503,195
Other gains, net	2,442	1,161	5,309	3,373
Gain on derivatives, net	2,226	1,283	20,130	1,162
Gain (loss) on fair value option securities, net	(3,355)	5,926	10,367	443
Change in fair value of mortgage servicing rights	2,327	(11,757)	(41,944)	(12,269)
Gain on available for sale securities, net	2,394	2,166	11,684	9,926
Total other-than-temporary impairment losses	0	0	0	(781)
Portion of loss recognized in other comprehensive income	0	0	0	689
Net impairment losses recognized in earnings	0	0	0	(92)
Total other operating revenue	191,342	163,436	539,968	505,738
Other operating expense [Abstract]
Personnel	143,185	129,062	421,518	390,305
Business promotion	6,839	5,922	19,238	19,435
Charitable contributions to BOKF Foundation	0	796	0	796
Professional fees and services	14,038	10,147	39,955	29,766
Net occupancy and equipment	20,111	18,689	58,554	56,660
Insurance	9,390	4,864	23,784	14,960
Data processing and communications	33,331	30,708	98,150	91,135
Printing, postage and supplies	3,790	3,376	11,586	10,390
Net losses (gains) and operating expenses of repossessed assets	(926)	267	1,732	1,103
Amortization of intangible assets	1,521	1,089	5,304	3,269
Mortgage banking costs	16,022	9,107	44,210	27,501
Other expense	14,819	10,601	37,714	26,686
Total other operating expense	262,120	224,628	761,745	672,006
Net income before taxes	107,068	109,944	266,253	344,325
Federal and state income taxes	31,956	34,128	83,881	113,142
Net income	75,112	75,816	182,372	231,183
Net income (loss) attributable to non-controlling interests	835	925	(270)	2,219
Net income attributable to BOK Financial Corporation shareholders	$ 74,277	$ 74,891	$ 182,642	$ 228,964
Earnings per share: [Abstract]
Basic	$ 1.13	$ 1.09	$ 2.77	$ 3.33
Diluted	$ 1.13	$ 1.09	$ 2.76	$ 3.32
Average shares used in computation: [Abstract]
Basic	65,085,392	67,668,076	65,208,774	68,004,508
Diluted	65,157,841	67,762,483	65,263,566	68,104,017
Dividends declared per share	$ 0.43	$ 0.42	$ 1.29	$ 1.26