Fair Value Measurements, Measured On Recurring Basis Significant Unobservable Inputs (Details) (Fair Value, Inputs, Level 3 [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Available for sale Securities [Member] | Municipal and other tax-exempt securities [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	$ 17,805,000	$ 40,702,000
Transfers to Level 3 from Level 2	0	0
Purchases and capital calls	0	0
Redemptions and distributions	(7,487,000)	(19,238,000)
Proceeds from sales	0
Other comprehensive gain (loss)	10,000	(3,506,000)
Balance at end of period	10,093,000	17,805,000
Available for sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0
Available for sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Available for sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	(235,000)	1,216,000
Available for sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	(1,369,000)
Available for sale Securities [Member] | Municipal and other tax-exempt securities [Member] | Charitable Contributions to BOKF Foundation [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0
Available for sale Securities [Member] | Other debt securities [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	4,712,000	5,399,000
Transfers to Level 3 from Level 2	0	0
Purchases and capital calls	0	0
Redemptions and distributions	(500,000)	(500,000)
Proceeds from sales	0
Other comprehensive gain (loss)	(62,000)	(187,000)
Balance at end of period	4,150,000	4,712,000
Available for sale Securities [Member] | Other debt securities [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0
Available for sale Securities [Member] | Other debt securities [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Available for sale Securities [Member] | Other debt securities [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Available for sale Securities [Member] | Other debt securities [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Available for sale Securities [Member] | Other debt securities [Member] | Charitable Contributions to BOKF Foundation [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0
Available for sale Securities [Member] | Equity securities and mutual funds [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	4,207,000	2,161,000
Transfers to Level 3 from Level 2	0	0
Purchases and capital calls	0	0
Redemptions and distributions	0	0
Proceeds from sales	0
Other comprehensive gain (loss)	(1,787,000)	2,046,000
Balance at end of period	0	4,207,000
Available for sale Securities [Member] | Equity securities and mutual funds [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0
Available for sale Securities [Member] | Equity securities and mutual funds [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Available for sale Securities [Member] | Equity securities and mutual funds [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Available for sale Securities [Member] | Equity securities and mutual funds [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Available for sale Securities [Member] | Equity securities and mutual funds [Member] | Charitable Contributions to BOKF Foundation [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	(2,420,000)
Residential Mortgage Loans Held for Sale [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	0	0
Transfers to Level 3 from Level 2	13,644,000	0
Purchases and capital calls	0	0
Redemptions and distributions	0	0
Proceeds from sales	(1,176,000)
Other comprehensive gain (loss)	0	0
Balance at end of period	11,856,000	0
Residential Mortgage Loans Held for Sale [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	(612,000)
Residential Mortgage Loans Held for Sale [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Residential Mortgage Loans Held for Sale [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Residential Mortgage Loans Held for Sale [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Residential Mortgage Loans Held for Sale [Member] | Charitable Contributions to BOKF Foundation [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0
Other Assets [Member] | Private equity funds [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Balance at beginning of period	27,341,000	28,169,000
Transfers to Level 3 from Level 2	0	0
Purchases and capital calls	1,012,000	1,415,000
Redemptions and distributions	(7,473,000)	(5,294,000)
Proceeds from sales	0
Other comprehensive gain (loss)	0	0
Balance at end of period	25,627,000	27,341,000
Other Assets [Member] | Private equity funds [Member] | Mortgage banking revenue [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0
Other Assets [Member] | Private equity funds [Member] | Gain (loss) on assets [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	4,747,000	3,051,000
Other Assets [Member] | Private equity funds [Member] | Gain on available for sale securities, net [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Other Assets [Member] | Private equity funds [Member] | Other-than-temporary impairment losses [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	0	0
Other Assets [Member] | Private equity funds [Member] | Charitable Contributions to BOKF Foundation [Member]
Fair Value Assets Measured on Recurring Basis Unobservable Reconciliation [Roll Forward]
Gain (loss) recognized in earnings	$ 0