Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest and dividend revenue [Abstract]
Loans	$ 581,030	$ 529,683	$ 502,753
Residential mortgage loans held for sale	12,658	13,602	10,143
Trading securities	8,527	2,240	1,945
Investment securities	16,894	18,098	18,891
Available for sale securities	175,321	174,829	185,107
Fair value option securities	6,723	9,264	3,611
Restricted equity securities	17,238	13,532	7,040
Interest-bearing cash and cash equivalents	10,726	5,580	2,749
Total interest and dividend revenue	829,117	766,828	732,239
Interest expense [Abstract]
Deposits	40,494	44,170	50,683
Borrowed funds	35,336	14,204	7,672
Subordinated debentures	6,059	5,100	8,690
Total interest expense	81,889	63,474	67,045
Net interest and dividend revenue	747,228	703,354	665,194
Provision for credit losses	65,000	34,000	0
Net interest and dividend revenue after provision for credit losses	682,228	669,354	665,194
Other operating revenue [Abstract]
Brokerage and trading revenue	138,377	129,556	134,437
Transaction card revenue	135,758	128,621	123,689
Fiduciary and asset management revenue	135,477	126,153	115,652
Deposit service charges and fees	92,193	90,431	90,911
Mortgage banking revenue	133,914	126,002	109,093
Other revenue	51,029	49,883	47,537
Total fees and commissions	686,748	650,646	621,319
Other gains, net	4,030	5,702	2,953
Gain (loss) on derivatives, net	(15,685)	430	2,776
Gain (loss) on fair value option securities, net	(10,555)	(3,684)	10,189
Change in fair value of mortgage servicing rights	(2,193)	(4,853)	(16,445)
Gain on available for sale securities, net	11,675	12,058	1,539
Total other-than-temporary impairment losses	0	(2,443)	(373)
Portion of loss recognized in other comprehensive income	0	624	0
Net impairment losses recognized in earnings	0	(1,819)	(373)
Total other operating revenue	674,020	658,480	621,958
Other operating expense [Abstract]
Personnel	553,119	515,298	476,931
Business promotion	26,582	27,851	26,649
Charitable contributions to BOKF Foundation	2,000	796	4,267
Professional fees and services	56,783	40,123	44,440
Net occupancy and equipment	80,024	76,016	77,232
Insurance	32,489	20,375	18,578
Data processing and communications	131,841	122,383	115,225
Printing, postage and supplies	15,584	13,498	13,518
Net losses and operating expenses of repossessed assets	3,359	1,446	6,019
Amortization of intangible assets	6,862	4,359	3,965
Mortgage banking costs	61,387	38,813	31,705
Other expense	47,560	35,233	28,993
Total other operating expense	1,017,590	896,191	847,522
Net income before taxes	338,658	431,643	439,630
Federal and state income taxes	106,377	139,384	144,151
Net income	232,281	292,259	295,479
Net income (loss) attributable to non-controlling interests	(387)	3,694	3,044
Net income attributable to BOK Financial Corporation shareholders	$ 232,668	$ 288,565	$ 292,435
Earnings per share: [Abstract]
Basic (in dollars per share)	$ 3.53	$ 4.22	$ 4.23
Diluted (in dollars per share)	$ 3.53	$ 4.21	$ 4.22
Average shares used in computation: [Abstract]
Basic (in shares)	65,085,627	67,594,689	68,394,194
Diluted (in shares)	65,143,898	67,691,658	68,544,770
Dividends declared per share (in dollars per share)	$ 1.73	$ 1.69	$ 1.62