Federal and State Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Amount [Abstract]
Federal statutory tax	$ 39,717	$ 40,768
Tax exempt revenue	(2,246)	(1,991)
Effect of state income taxes, net of federal benefit	2,615	2,870
Utilization of tax credits: [Abstract]
Low-income housing tax credit, net of amortization	(757)	(991)
Other tax credits	(521)	(381)
Bank-owned life insurance	(804)	(768)
Charitable contributions to BOKF Foundation	0	(427)
Other, net	380	357
Total	$ 38,384us-gaap_IncomeTaxExpenseBenefit	$ 39,437us-gaap_IncomeTaxExpenseBenefit
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory tax (in hundredths)	35.00%	35.00%
Tax exempt revenue (in hundredths)	(2.00%)	(1.70%)
Effect of state income taxes, net of federal benefit (in hundredths)	2.30%	2.50%
Utilization of tax credits: [Abstract]
Low-income housing tax credit, net of amortization (in hundreths)	(0.70%)	(0.90%)
Other tax credits (in hundreths)	(0.50%)	(0.30%)
Bank-owned life insurance (in hundredths)	(0.70%)	(0.70%)
Charitable contribution to BOKF Foundation (in hundredths)	0.00%	(0.40%)
Other, net (in hundredths)	0.40%	0.40%
Total (in hundredths)	33.80%	33.90%

Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other low income housing tax credits, net of amortization.

No definition available.