Consolidated Statements of Earnings (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Interest revenue [Abstract]
Loans	$ 125,113	$ 126,983
Residential mortgage loans held for sale	1,792	1,768
Trading securities	478	300
Taxable securities	3,798	4,434
Tax-exempt securities	1,028	977
Total investment securities	4,826	5,411
Taxable securities	55,019	59,656
Tax-exempt securities	604	601
Total available for sale securities	55,623	60,257
Fair value optioin securities	1,165	3,487
Funds sold and resell agreements	2	2
Total interest revenue	188,999	198,208
Interest expense [Abstract]
Deposits	14,881	17,498
Borrowed funds	1,554	1,589
Subordinated debentures	2,159	5,552
Total interest expense	18,594	24,639
Net interest revenue	170,405	173,569
Provision for credit losses	(8,000)	0
Net interest revenue after provision for credit losses	178,405	173,569
Other operating revenue [Abstract]
Brokerage and trading revenue	31,751	31,111
Transaction card revenue	27,692	25,430
Trust fees and commissions	22,313	18,438
Deposit service charges and fees	22,966	24,379
Mortgage banking revenue	39,976	33,078
Bank-owned life insurance	3,226	2,871
Other revenue	10,187	9,264
Total fees and commissions	158,111	144,571
Gain (loss) on assets, net	467	(3,693)
Gain (loss) on derivatives, net	(941)	(2,473)
Gain (loss) on fair value option securities, net	(3,171)	(1,733)
Gain on available for sale securities, net	4,855	4,331
Total other-than-temporary impairment losses	0	(505)
Portion of loss recognized in (reclassified from) other comprehensive income	(247)	(3,217)
Net impairment losses recognized in earnings	(247)	(3,722)
Total other operating revenue	159,074	137,281
Other operating expense [Abstract]
Personnel	125,654	114,769
Business promotion	5,453	4,388
Professional fees and services	6,985	7,599
Net occupancy and equipment	16,481	16,023
Insurance	3,745	3,866
Data processing and communications	25,450	22,144
Printing, postage and supplies	3,674	3,311
Net losses and expenses of repossessed assets	1,246	2,245
Amortization of intangible assets	876	575
Mortgage banking costs	7,354	8,439
Change in fair value of mortgage servicing rights	(2,658)	(7,127)
Other expense	7,064	5,905
Total other operating expense	201,324	182,137
Income before taxes	136,155	128,713
Federal and state income tax	47,096	45,520
Net income	89,059	83,193
Net income (loss) attributable to non-controlling interest	1,095	(422)
Net income attributable to BOK Financial Corporation	$ 87,964	$ 83,615
Earnings per share: [Abstract]
Basic (in dollars per share)	$ 1.28	$ 1.22
Diluted (in dollars per share)	$ 1.28	$ 1.22
Average shares used in computation: [Abstract]
Basic (in shares)	67,814,550	67,665,300
Diluted (in shares)	68,040,180	67,941,895
Dividends declared per share (in dollars per share)	$ 0.38	$ 0.33