Goodwill and Related Intangible Assets (Schedule of Acquired Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	$ 116,339	$ 113,646
Total acquired intangible assets, Gross Carrying Amount	161,446	158,366
Accumulated Amortization, Finite-lived intangible assets	55,678	47,576
Total acquired intangible assets, Accumulated Amortization	55,678	47,576
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	5,876	5,808
Accumulated Amortization, Finite-lived intangible assets	3,062	2,427
Unpatented technology and patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	28,107	26,720
Accumulated Amortization, Finite-lived intangible assets	12,033	10,041
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	80,707	78,569
Accumulated Amortization, Finite-lived intangible assets	39,652	33,585
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	1,649	1,649
Accumulated Amortization, Finite-lived intangible assets	931	623
Backlog
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	0	900
Accumulated Amortization, Finite-lived intangible assets	0	900
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Indefinite-lived intangible assets	45,107	44,720
Accumulated Amortization, Indefinite-lived intangible assets	$ 0	$ 0
Minimum | Trademarks
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years
Minimum | Unpatented technology and patents
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years
Minimum | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years
Minimum | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	4 years
Minimum | Backlog
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	6 months
Maximum | Trademarks
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	15 years
Maximum | Unpatented technology and patents
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	20 years
Maximum | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	17 years
Maximum | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	10 years
Maximum | Backlog
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life	2 years