Consolidated Statements of Earnings (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Interest revenue [Abstract]
Loans	$ 141,560	$ 133,197	$ 280,672	$ 259,893
Residential mortgage loans held for sale	3,508	3,892	6,208	6,841
Trading securities	616	442	1,140	949
Taxable securities	3,069	3,251	6,244	6,577
Tax-exempt securities	1,148	1,315	2,360	2,659
Total investment securities	4,217	4,566	8,604	9,236
Taxable securities	43,345	42,355	88,277	85,460
Tax-exempt securities	527	563	1,062	1,183
Total available for sale securities	43,872	42,918	89,339	86,643
Fair value option securities	2,062	2,320	4,651	4,323
Restricted equity securities	3,863	3,228	8,174	5,825
Interest-bearing cash and cash equivalents	2,569	1,250	5,275	2,672
Total interest revenue	202,267	191,813	404,063	376,382
Interest expense [Abstract]
Deposits	9,997	11,266	20,539	23,371
Borrowed funds	8,780	3,121	16,752	5,694
Subordinated debentures	878	1,695	1,588	3,860
Total interest expense	19,655	16,082	38,879	32,925
Net interest revenue	182,612	175,731	365,184	343,457
Provision for credit losses	20,000	4,000	55,000	4,000
Net interest revenue after provision for credit losses	162,612	171,731	310,184	339,457
Other operating revenue [Abstract]
Brokerage and trading revenue	39,530	36,012	71,871	67,719
Transaction card revenue	34,950	32,778	67,304	63,788
Fiduciary and asset management revenue	34,813	32,712	66,869	64,181
Deposit service charges and fees	22,618	22,328	45,160	44,012
Mortgage banking revenue	38,224	36,846	72,654	76,166
Other revenue	13,352	11,871	25,256	22,672
Total fees and commissions	183,487	172,547	349,114	338,538
Other gains, net	1,307	1,457	2,867	2,212
Gain (loss) on derivatives, net	10,766	(1,032)	17,904	(121)
Gain (loss) on fair value option securities, net	4,279	(8,130)	13,722	(5,483)
Change in fair value of mortgage servicing rights	(16,283)	8,010	(44,271)	(512)
Gain on available for sale securities, net	5,326	3,433	9,290	7,760
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	188,882	176,285	348,626	342,302
Other operating expense [Abstract]
Personnel	142,490	132,695	278,333	261,243
Business promotion	6,703	7,765	12,399	13,513
Professional fees and services	14,158	9,560	25,917	19,619
Net occupancy and equipment	19,677	18,927	38,443	37,971
Insurance	7,129	5,116	14,394	10,096
Data processing and communications	32,802	30,655	64,819	60,427
Printing, postage and supplies	3,889	3,553	7,796	7,014
Net losses and operating expenses of repossessed assets	1,588	223	2,658	836
Amortization of intangible assets	2,624	1,090	3,783	2,180
Mortgage banking costs	15,809	8,227	28,188	18,394
Other expense	7,856	9,302	22,895	16,085
Total other operating expense	254,725	227,113	499,625	447,378
Net income before taxes	96,769	120,903	159,185	234,381
Federal and state income taxes	30,497	40,630	51,925	79,014
Net income	66,272	80,273	107,260	155,367
Net income (loss) attributable to non-controlling interests	471	1,043	(1,105)	1,294
Net income attributable to BOK Financial Corporation shareholders	$ 65,801	$ 79,230	$ 108,365	$ 154,073
Earnings per share: [Abstract]
Basic (in dollars per share)	$ 1.00	$ 1.15	$ 1.64	$ 2.23
Diluted (in dollars per share)	$ 1.00	$ 1.15	$ 1.64	$ 2.23
Average shares used in computation: [Abstract]
Basic (in shares)	65,245,887	68,096,341	65,271,214	68,175,327
Diluted (in shares)	65,302,926	68,210,353	65,317,177	68,277,386
Dividends declared per share (in dollars per share)	$ 0.43	$ 0.42	$ 0.86	$ 0.84