Acquisitions, Goodwill And Other Intangible Assets (Schedule Of Goodwill By Reportable Segment) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Segment Reporting Information
Net balance – December 31, 2017	$ 124,183
Acquisitions – 2018	27,147
Other	501
Net balance – June 30, 2018	151,831
OEM Segment
Segment Reporting Information
Net balance – December 31, 2017	109,641
Acquisitions – 2018	23,921
Other	501
Net balance – June 30, 2018	134,063
Aftermarket Segment
Segment Reporting Information
Net balance – December 31, 2017	14,542
Acquisitions – 2018	3,226
Other	0
Net balance – June 30, 2018	$ 17,768