Related Parties Related Parties (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Loans and Leases Receivable, Related Parties [Roll Forward]
Related Parties, Loans, Beginning balance	$ 99,340		$ 168,935
Loans and Leases Receivable, Related Parties, Additions	644,715		300,080
Loans and Leases Receivable, Related Parties, Collections	(684,942)		(285,909)
Loans and Leases Receivable Related Parties Adjustments	(9,170)	[1]	(83,766)	[1]
Related Parties, Loans, Ending balance	49,943		99,340		168,935
Related Party Transaction [Line Items]
Lease payments on office space in facilities owned by related party afffiliates	21,700,000		20,600,000		21,200,000
Loan commitment secured by tax-exempt bonds purchased from a trust of which the related party is chairman of the trust	6,600,000,000
Board of Directors Chairman [Member]
Related Party Transaction [Line Items]
Lease payments on office space in facilities owned by related party afffiliates	1,100,000		1,100,000		1,100,000
President [Member]
Related Party Transaction [Line Items]
Loan commitment secured by tax-exempt bonds purchased from a trust of which the related party is chairman of the trust	25,000,000
Executive Officer [Member]
Related Party Transaction [Line Items]
Percentage of investment funds' assets held by clients	99.00%
Assets Held in Cavanal Hill Funds	$ 2,400,000,000

[1] 1 Adjustments generally consist of changes in status as a related party.