Goodwill and Other Intangible Assets, Net (Other Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 197,603	$ 190,757
Accumulated Amortization	(80,485)	(64,313)
Intangible assets amortization expense	14,600	15,600	$ 11,800
Finite-Lived Intangible Assets, Net, Amortization Expense, Rolling Maturity [Abstract]
2018	13,866
2019	12,456
2020	11,957
2021	11,435
2022	11,042
Customer lists / relationships
Finite-Lived Intangible Assets [Line Items]
Gross Amount	159,592	154,745
Accumulated Amortization	$ (65,036)	(51,800)
Customer lists / relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	6 years
Customer lists / relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	26 years
Developed technologies
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 20,148	19,049
Accumulated Amortization	$ (2,790)	(1,394)
Developed technologies | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	10 years
Developed technologies | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	20 years
Trademarks / trade names
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 8,995	8,344
Accumulated Amortization	$ (3,905)	(3,250)
Trademarks / trade names | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	3 years
Trademarks / trade names | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	15 years
Noncompete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 8,345	8,096
Accumulated Amortization	$ (8,319)	(7,444)
Noncompete agreements | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	1 year
Noncompete agreements | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	9 years
Patents
Finite-Lived Intangible Assets [Line Items]
Amortization Period	17 years
Gross Amount	$ 523	523
Accumulated Amortization	(435)	$ (425)
U.K. Composites
Finite-Lived Intangible Assets [Line Items]
Other intangible assets net	11,300
Engineering Services
Finite-Lived Intangible Assets [Line Items]
Other intangible assets net	$ 1,200