Other Borrowings (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Borrowings [Line Items]
Balance		$ 5,717,302	$ 6,277,866	$ 3,726,277
Average Balance		$ 6,901,856	$ 5,880,647	$ 3,699,621
Rate		0.60%	0.36%	0.43%
U.S. government agency mortgage-backed securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 655,529	$ 685,458
Fair Value		655,851	688,485
Repurchase Liability	[1]	$ 668,661	$ 722,444
Average Rate (in hundredths)		0.02%	0.02%
U.S. government agency mortgage-backed securities [Member] | Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 655,529	$ 685,458
Fair Value		655,851	688,485
Repurchase Liability	[1]	$ 668,661	$ 722,444
Average Rate (in hundredths)		0.02%	0.02%
U.S. government agency mortgage-backed securities [Member] | Long-term [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Amortized Cost		$ 0	$ 0
Fair Value		0	0
Repurchase Liability	[1]	$ 0	$ 0
Average Rate (in hundredths)		0.00%	0.00%
Parent Company and other non-bank subsidiaries [Member]
Other Borrowings [Line Items]
Balance		$ 152,949	$ 0	$ 0
Average Balance		$ 77,112	0	$ 0
Rate		5.86%		0.00%
Other borrowings, Maturities [Abstract]
2017		$ 0
2018		0
2019		0
2020		0
2021		0
Thereafter		152,949
Parent Company and other non-bank subsidiaries [Member] | Other Borrowings [Member]
Other Borrowings [Line Items]
Balance		8,309	0	$ 0
Average Balance		$ 2,684	$ 0	$ 0
Rate		13.19%	0.00%	0.00%
Parent Company and other non-bank subsidiaries [Member] | Trust preferred debt [Member]
Other Borrowings [Line Items]
Balance		$ 7,217	$ 0	$ 0
Rate		3.28%	0.00%	0.00%
Average Balance		$ 611	$ 0	$ 0
Rate		3.27%	0.00%	0.00%
Maximum Outstanding At Any Month End		$ 7,217	$ 0	$ 0
Parent Company and other non-bank subsidiaries [Member] | Trust preferred debt, 2003 issuance [Member]
Other Borrowings [Line Items]
Balance		$ 3,100
Other borrowings, Other Disclosures [Abstract]
Maturity date		Sep. 17, 2033
Interest rate description		three-month LIBOR plus 2.95%
Parent Company and other non-bank subsidiaries [Member] | Trust preferred debt, 2006 issuance [Member]
Other Borrowings [Line Items]
Balance		$ 4,100
Other borrowings, Other Disclosures [Abstract]
Maturity date		Dec. 15, 2036
Interest rate description		three-month LIBOR plus 1.82%
Parent Company and other non-bank subsidiaries [Member] | Other [Member]
Other Borrowings [Line Items]
Balance		$ 1,092	$ 0	$ 0
Rate		8.27%	0.00%	0.00%
Average Balance		$ 2,073	$ 0	$ 0
Rate		16.11%	0.00%	0.00%
Maximum Outstanding At Any Month End		$ 3,157	$ 0	$ 0
Parent Company and other non-bank subsidiaries [Member] | Other, Pershing [Member]
Other Borrowings [Line Items]
Balance		0
Parent Company and other non-bank subsidiaries [Member] | Subordinated debentures [Member]
Other Borrowings [Line Items]
Balance		$ 144,640	$ 0	$ 0
Rate		5.60%	0.00%	0.00%
Average Balance		$ 74,428	$ 0	$ 0
Rate		5.59%	0.00%	0.00%
Maximum Outstanding At Any Month End		$ 145,393	$ 0	$ 0
Parent Company and other non-bank subsidiaries [Member] | Subordinated debentures, 2016 issuance [Member]
Other borrowings, Other Disclosures [Abstract]
Amount of debt issuance		$ 150,000
Maturity date		Jun. 30, 2056
Stated interest rate		5.375%
Debt Instrument, Call Date, Earliest		Jun. 30, 2021
BOKF, NA [Member]
Other Borrowings [Line Items]
Balance		$ 5,564,353	6,277,866	3,726,277
Average Balance		$ 6,824,744	$ 5,880,647	$ 3,699,621
Rate		0.54%	0.36%	0.43%
Other borrowings, Maturities [Abstract]
2017		$ 5,549,587
2018		711
2019		956
2020		961
2021		965
Thereafter		11,173
BOKF, NA [Member] | Funds purchased [Member]
Other Borrowings [Line Items]
Balance		$ 57,929	$ 491,192	$ 57,031
Rate		0.38%	0.15%	0.05%
Average Balance		$ 78,222	$ 73,219	$ 494,220
Rate		0.24%	0.09%	0.07%
Maximum Outstanding At Any Month End		$ 567,103	$ 491,192	$ 1,548,676
Other borrowings, Other Disclosures [Abstract]
Number of days to maturity, minimum		1 day
Number of days to maturity, maximum		90 days
BOKF, NA [Member] | Repurchase agreements [Member]
Other Borrowings [Line Items]
Balance		$ 668,661	$ 722,444	$ 1,187,489
Rate		0.02%	0.02%	0.04%
Average Balance		$ 589,145	$ 623,921	$ 928,767
Rate		0.04%	0.04%	0.06%
Maximum Outstanding At Any Month End		$ 668,661	$ 1,008,144	$ 1,187,489
Other borrowings, Other Disclosures [Abstract]
Number of days to maturity, maximum		90 days
Accrued interest payable		$ 0	0
BOKF, NA [Member] | Other Borrowings [Member]
Other Borrowings [Line Items]
Balance		4,837,763	4,837,880	2,133,774
Average Balance		$ 6,016,963	$ 4,957,175	$ 1,928,742
Rate		0.57%	0.33%	0.35%
BOKF, NA [Member] | Federal Home Loan Bank advances [Member]
Other Borrowings [Line Items]
Balance		$ 4,800,000	$ 4,800,000	$ 2,103,400
Rate		0.72%	0.48%	0.25%
Average Balance		$ 5,985,656	$ 4,921,739	$ 1,894,966
Rate		0.55%	0.28%	0.24%
Maximum Outstanding At Any Month End		$ 6,500,000	$ 5,000,000	$ 3,453,400
Other borrowings, Other Disclosures [Abstract]
Federal Home Loan Banks, Letters of credit issued to secure public funds		242,000
Unused credit available pursuant to the FHLB's collateral policies		1,300,000
BOKF, NA [Member] | GNMA repurchase liability [Member]
Other Borrowings [Line Items]
Balance		$ 22,471	$ 19,478	$ 14,298
Rate		4.26%	4.75%	5.05%
Average Balance		$ 15,637	$ 16,668	$ 17,343
Rate		4.74%	4.95%	5.20%
Maximum Outstanding At Any Month End		$ 22,471	$ 19,478	$ 24,980
BOKF, NA [Member] | Other [Member]
Other Borrowings [Line Items]
Balance		$ 15,292	$ 18,402	$ 16,076
Rate		2.66%	2.70%	2.73%
Average Balance		$ 15,670	$ 18,768	$ 16,433
Rate		2.41%	2.35%	2.32%
Maximum Outstanding At Any Month End		$ 15,797	$ 26,058	$ 16,582
BOKF, NA [Member] | Subordinated debentures [Member]
Other Borrowings [Line Items]
Balance		$ 0	$ 226,350	$ 347,983
Rate		0.00%	1.05%	2.35%
Average Balance		$ 140,414	$ 226,332	$ 347,892
Rate		1.35%	1.84%	2.50%
Maximum Outstanding At Any Month End		$ 226,434	$ 348,076	$ 347,983
BOKF, NA [Member] | Subordinated debentures, 2007 issuance [Member]
Other Borrowings [Line Items]
Balance			$ 226,000
Other borrowings, Other Disclosures [Abstract]
Amount of debt issuance		$ 250,000
Maturity date		May 15, 2017
Interest rate description		fixed rate of 5.75% through May 14, 2012 and is based on a floating rate of three-month LIBOR plus 0.69% thereafter

[1] 1 BOK Financial maintains control over the securities underlying overnight repurchase agreements and generally transfers control over securities underlying longer-term dealer repurchase agreements to the respective counterparty.