Commitments and Contingent Liabilities (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2017 USD ($) shares	Dec. 31, 2016 USD ($)
BOKF Equity, LLC [Member]
Litigation Settlement [Abstract]
Number of Private Equity Funds of which the Entity is a General Partner	2
Contingent Obligations For Additional Investments in Private Equity Funds	$ 4,000,000
Cavanal Hill Funds [Member]
Litigation Settlement [Abstract]
The Net Asset Value of Units in Mutual Funds (per unit)	1.00
Settled Litigation [Member] | Deposit Account Posting Class Action [Member]
Litigation Settlement [Abstract]
Litigation Settlement, Amount		$ 7,800,000
Judicial Ruling [Member] | Misuse of Revenues Pledged to Municipal Bonds [Member]
Litigation Settlement [Abstract]
Litigation Settlement, Amount	$ 600,000
Outstanding principal, accrued interest and other amounts required by bond documents	73,000,000
Disgorged fees	$ 1,067,721
Pending Litigation [Member] | Misuse of Revenues Pledged to Municipal Bonds [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	2
Pending Litigation [Member] | Bank Participation in Fraudulent Sale of Securities by Principals [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	19
Pending Litigation [Member] | Purchase of facilities from principals subject to SEC New Jersey proceedings [Member]
Litigation Settlement [Abstract]
Outstanding principal, accrued interest and other amounts required by bond documents	$ 60,000,000
Number of individuals who purchased facilities from the principals subject to SEC New Jersey proceedings	2
Number of principals in SEC New Jersey proceedings	2
Pending Litigation [Member] | Ownership of deposit accounts [Member]
Litigation Settlement [Abstract]
Loss Contingency, Number of Plaintiffs	2
Amount paid by the bank from creditor accounts to judgment creditor	$ 4,200,000
Loss Contingency, Damages Sought, Value	$ 7,000,000
Visa Membership [Member]
Loss Contingencies [Line Items]
Number of Visa Class B Shares Owned by Entity (in shares) | shares	252,233
Number of Visa Class A Shares Visa Class B Shares Are Convertible To (in shares) | shares	415,755