Commitments and Contingent Liabilities (Details) (USD $)		3 Months Ended			0 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 Property Lease Guarantee [Member]	Mar. 31, 2012 City of Tulsa Property Lease Guarantee [Member]	Mar. 31, 2012 Bank of Oklahoma, National Association [Member] Putative Class Actions [Member]	Oct. 11, 2011 Bank of Oklahoma, National Association [Member] Invalidated Settlement by Oklahoma Supreme Court [Member]	Mar. 31, 2012 Parent Company [Member] Visa Membership [Member]	Mar. 31, 2012 Cavanal Hill Funds [Member]	Mar. 31, 2012 BOKF Equity, LLC [Member]
Loss Contingencies [Line Items]
Number of Putative Class Actions Named as a Defendant				3
Settlement Agreement, Counterparty's Name					City of Tulsa
Settlement Agreement, Amount				$ 19,000,000	$ 7,100,000
Amount of Contingent Liability Recognized from Visa Membership						581,000
Amount of Proportionate Receivable Recognized From Visa Membership						581,000
Number of Visa Class B Shares Owned by Entity (in shares)						251,837
Optional Period After Which Class B Shares Can be Converted to Class A Shares (in years)						3 Y
Current Exchange Rate For Class A shares For Each Class B Share						0.4881
Mutual Fund Investment in US Treasury Securities							1,300,000,000
Mutual Fund Investment in Cash Management							857,000,000
Mutual Fund Investment in Tax-Free Money Market Funds							412,000,000
The Net Asset Value of Units in Mutual Funds (per unit)							$ 1.00
Number of private equity funds sponsored	2
Number of Private Equity Funds of which the Entity is a General Partner								2
Contingent Obligations For Additional Investments in Private Equity Funds								9,300,000
Guarantor Obligations [Line Items]
Contingent Obligation For Guaranteed Rents		16,400,000	28,700,000
Guaranteed Percentage To Be Received (in hundredths)		80.00%
Maximum Amount To Be Received Under Rent Agreement With City Of Tulsa		$ 4,500,000