Acquisitions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Jun. 30, 2015	Dec. 31, 2015	Mar. 31, 2015
Business Acquisition [Line Items]
Purchase Price Allocation, Goodwill	$ 383,789		$ 385,461	$ 377,780
MBT Bancshares [Member]
Business Acquisition [Line Items]
Agreed to purchase price amount of acquisition target			$ 102,500
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Purchase Price	7,700
Purchase Price Allocation, Intangible Assets	5,300
Purchase Price Allocation, Goodwill	3,300
Heartland Food Products, LLC [Member]
Business Acquisition [Line Items]
Purchase Price		$ 18,000
Purchase Price Allocation, Intangible Assets	11,000
Purchase Price Allocation, Goodwill	$ 2,700