Business Acquisitions and Divestitures - Intangible Assets Acquired (Details) - USD ($) $ in Thousands			12 Months Ended
	Feb. 23, 2017	Oct. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
C&CA
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values	$ 10,923		$ 10,923
Lavante
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values		$ 6,178		$ 6,178
Customer relationships | C&CA
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values	$ 9,556		9,556
Acquired finite-lived Intangible Assets, Remaining useful lives	14 years
Customer relationships | Lavante
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values				0
Non-compete | C&CA
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values	$ 1,232		1,232
Acquired finite-lived Intangible Assets, Remaining useful lives	4 years
Non-compete | Lavante
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values				0
Trademarks | C&CA
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values	$ 135		135
Acquired finite-lived Intangible Assets, Remaining useful lives	4 years
Trademarks | Lavante
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values		$ 163		0
Acquired finite-lived Intangible Assets, Remaining useful lives		4 years
Patents | Lavante
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values		$ 114
Acquired finite-lived Intangible Assets, Remaining useful lives		1 year
Software | C&CA
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values			$ 0
Software | Lavante
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired, Fair Values		$ 5,901		$ 6,178
Acquired finite-lived Intangible Assets, Remaining useful lives		4 years