Acquisitions, Goodwill And Other Intangible Assets (Schedule of Other Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets
Accumulated amortization	$ 90,658	$ 75,198
Net balance	19,573	17,758	$ 16,055
Indefinite-lived Intangible Assets
Total gross cost	220,790	188,141
Total net balance	130,132	112,943
Purchased Research and Development
Indefinite-lived Intangible Assets
Gross cost and net balance	4,687	4,687
OEM Segment
Indefinite-lived Intangible Assets
Total net balance	116,648	97,689
Aftermarket Segment
Indefinite-lived Intangible Assets
Total net balance	13,484	15,254
Customer Relationships
Finite-Lived Intangible Assets
Gross cost	138,687	110,784
Accumulated amortization	42,276	32,414
Net balance	$ 96,411	$ 78,370
Customer Relationships | Minimum
Finite-Lived Intangible Assets
Estimated useful life in years	6 years	6 years
Customer Relationships | Maximum
Finite-Lived Intangible Assets
Estimated useful life in years	16 years	16 years
Patents
Finite-Lived Intangible Assets
Gross cost	$ 57,576	$ 56,468
Accumulated amortization	38,764	34,066
Net balance	$ 18,812	$ 22,402
Patents | Minimum
Finite-Lived Intangible Assets
Estimated useful life in years	3 years	3 years
Patents | Maximum
Finite-Lived Intangible Assets
Estimated useful life in years	19 years	19 years
Tradenames
Finite-Lived Intangible Assets
Gross cost	$ 10,995	$ 10,041
Accumulated amortization	5,381	5,667
Net balance	$ 5,614	$ 4,374
Tradenames | Minimum
Finite-Lived Intangible Assets
Estimated useful life in years	3 years	3 years
Tradenames | Maximum
Finite-Lived Intangible Assets
Estimated useful life in years	15 years	15 years
Non-compete Agreements
Finite-Lived Intangible Assets
Gross cost	$ 8,536	$ 5,852
Accumulated amortization	4,128	2,975
Net balance	$ 4,408	$ 2,877
Non-compete Agreements | Minimum
Finite-Lived Intangible Assets
Estimated useful life in years	3 years	3 years
Non-compete Agreements | Maximum
Finite-Lived Intangible Assets
Estimated useful life in years	6 years	6 years
Other
Finite-Lived Intangible Assets
Gross cost	$ 309	$ 309
Accumulated amortization	109	76
Net balance	$ 200	$ 233
Other | Minimum
Finite-Lived Intangible Assets
Estimated useful life in years	2 years	2 years
Other | Maximum
Finite-Lived Intangible Assets
Estimated useful life in years	12 years	12 years