Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 223,426			$ 223,426		$ 221,662
Accumulated Amortization	(98,977)			(98,977)		(89,317)
Net Carrying Amount	124,449			124,449		132,345
Goodwill and long-lived asset impairment	870		$ 41,032	$ 870	$ 41,032
License agreements (3)
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)				1 year 9 months 25 days
Gross Carrying Amount	3,899			$ 3,899		4,497
Accumulated Amortization	(3,686)			(3,686)		(3,623)
Net Carrying Amount	213			$ 213		874
Leases
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)				2 years 3 months
Gross Carrying Amount	796			$ 796		796
Accumulated Amortization	(599)			(599)		(534)
Net Carrying Amount	197			$ 197		262
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)				9 years 7 months 5 days
Gross Carrying Amount	15,739			$ 15,739		15,464
Accumulated Amortization	(7,132)			(7,132)		(6,184)
Net Carrying Amount	8,607			$ 8,607		9,280
Non-competes
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)				4 years 9 months 10 days
Gross Carrying Amount	2,548			$ 2,548		1,197
Accumulated Amortization	(1,107)			(1,107)		(1,048)
Net Carrying Amount	1,441			$ 1,441		149
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)				9 years 1 month 30 days
Gross Carrying Amount	161,745			$ 161,745		160,423
Accumulated Amortization	(64,876)			(64,876)		(56,907)
Net Carrying Amount	96,869			$ 96,869		103,516
Patents and acquired technology
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)				6 years 1 month 10 days
Gross Carrying Amount	38,699			$ 38,699		39,285
Accumulated Amortization	(21,577)			(21,577)		(21,021)
Net Carrying Amount	17,122			17,122		$ 18,264
Hebna | Non-competes
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		$ 1,100
Hebna | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired		$ 1,300
Energy Services | Trademarks
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	300
Energy Services | Non-competes
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	200
Energy Services | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired	$ 700
Denmark | License agreements (3)
Finite-Lived Intangible Assets [Line Items]
Goodwill and long-lived asset impairment				500
Denmark | Trademarks
Finite-Lived Intangible Assets [Line Items]
Goodwill and long-lived asset impairment				100
Denmark | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Goodwill and long-lived asset impairment				$ 300