Business Acquisition (Details) - USD ($) $ in Thousands	Dec. 31, 2015	May. 18, 2015	Dec. 31, 2014	Oct. 07, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Goodwill	$ 63,934		$ 72,365		$ 58,554	$ 54,387
Kay Flow Industries, Inc.
Business Acquisition [Line Items]
Cash		$ 880
Accounts receivable		14,699
Inventory		25,094
Other assets		6,155
Intangibles		53,091
Goodwill		47,735
Property, plant and equipment		27,478
Accounts payable		(12,131)
Other current liabilities		(4,866)
Other liabilities		(28,706)
Total purchase price		$ 129,429
Auburn Bean and Grain
Business Acquisition [Line Items]
Cash				$ 12,491
Accounts receivable				9,012
Inventory				5,798
Other assets				2,665
Intangible assets				9,250
Goodwill				11,236
Property, plant and equipment				41,692
Accounts payable				(3,419)
Commodity derivatives				(2,733)
Other current liabilities				(1,281)
Long-term debt				(12,577)
Other liabilities				(11,239)
Total purchase price				$ 60,895