Goodwill and Intangible Assets Acquisitions (Details) - USD ($) $ in Thousands		Dec. 01, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Goodwill			$ 448,899	$ 385,461	$ 377,780
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Assets Under Management at time of acquisition			340,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Intangible assets			5,300	11,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Purchase Price			7,700	18,000
Goodwill			$ 3,300	$ 2,700
MBT Bancshares [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition		Dec. 01, 2016
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents		$ 166,215
Securities		14,431
Loans	[1]	444,482
Premises and equipments, net		8,035
Intangible assets		6,510
Other assets		3,599
Total assets acquired		643,272
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Deposits		598,735
Other borrowings		7,217
Other liabilities		980
Total liabilities assumed		606,932
Net assets acquired		36,340
Purchase Price		102,500
Goodwill		$ 66,160

[1] Loans are presented net of participations sold to BOKF NA.