Consolidated Statements of Earnings (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Interest revenue [Abstract]
Loans	$ 160,895	$ 139,112
Residential mortgage loans held for sale	1,836	2,700
Trading securities	5,183	524
Investment securities	4,171	4,387
Available for sale securities	43,372	45,467
Fair value option securities	2,380	2,589
Restricted equity securities	4,309	4,311
Interest-bearing cash and cash equivalents	4,244	2,706
Total interest revenue	226,390	201,796
Interest expense [Abstract]
Deposits	11,354	10,542
Borrowed funds	11,829	7,972
Subordinated debentures	2,025	710
Total interest expense	25,208	19,224
Net interest revenue	201,182	182,572
Provision for credit losses	0	35,000
Net interest revenue after provision for credit losses	201,182	147,572
Other operating revenue [Abstract]
Brokerage and trading revenue	33,623	32,341
Transaction card revenue	32,127	32,354
Fiduciary and asset management revenue	38,631	32,056
Deposit service charges and fees	23,030	22,542
Mortgage banking revenue	25,191	32,100
Other revenue	11,752	11,904
Total fees and commissions	164,354	163,297
Other gains, net	3,627	1,560
Gain (loss) on derivatives, net	(450)	7,138
Gain (loss) on fair value option securities, net	(1,140)	9,443
Change in fair value of mortgage servicing rights	1,856	(27,988)
Gain on available for sale securities, net	2,049	3,964
Total other operating revenue	170,296	157,414
Other operating expense [Abstract]
Personnel	136,425	133,562
Business promotion	6,717	5,696
Professional fees and services	12,379	11,759
Net occupancy and equipment	21,624	18,766
Insurance	6,404	7,265
Data processing and communications	33,940	32,017
Printing, postage and supplies	3,851	3,907
Net losses (gains) and operating expenses of repossessed assets	1,009	1,070
Amortization of intangible assets	1,802	1,159
Mortgage banking costs	13,003	12,330
Other expense	7,557	15,039
Total other operating expense	244,711	242,570
Net income before taxes	126,767	62,416
Federal and state income taxes	38,103	21,428
Net income	88,664	40,988
Net income (loss) attributable to non-controlling interests	308	(1,576)
Net income attributable to BOK Financial Corporation shareholders	$ 88,356	$ 42,564
Earnings per share: [Abstract]
Basic	$ 1.35	$ 0.64
Diluted	$ 1.35	$ 0.64
Average shares used in computation: [Abstract]
Basic	64,715,964	65,296,541
Diluted	64,783,737	65,331,428
Dividends declared per share	$ 0.44	$ 0.43