Goodwill and Related Intangible Assets (Schedule of Acquired Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	$ 106,755	$ 106,806
Total acquired intangible assets, Gross Carrying Amount	150,625	150,676
Accumulated Amortization, Finite-lived intangible assets	56,105	54,301
Total acquired intangible assets, Accumulated Amortization	56,105	54,301
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	6,114	6,094
Accumulated Amortization, Finite-lived intangible assets	3,669	3,518
Unpatented technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	28,644	28,644
Accumulated Amortization, Finite-lived intangible assets	14,352	13,881
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Finite-lived intangible assets	70,348	70,419
Accumulated Amortization, Finite-lived intangible assets	36,791	35,678
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	1,293	1,224
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Indefinite-lived intangible assets	43,870	43,870
Accumulated Amortization, Indefinite-lived intangible assets	$ 0	$ 0
Minimum | Trademarks
Finite-Lived Intangible Assets [Line Items]
Estimated Life	3 years
Minimum | Unpatented technology
Finite-Lived Intangible Assets [Line Items]
Estimated Life	5 years
Minimum | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Life	5 years
Minimum | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated Life	4 years
Maximum | Trademarks
Finite-Lived Intangible Assets [Line Items]
Estimated Life	15 years
Maximum | Unpatented technology
Finite-Lived Intangible Assets [Line Items]
Estimated Life	20 years
Maximum | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated Life	17 years
Maximum | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated Life	10 years