Segment Reporting (Schedule of Operating Profit by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information
Operating profit	$ 94,433	$ 49,153	$ 159,481	$ 162,565
Operating Segments | OEM Segment
Segment Reporting Information
Operating profit	65,533	38,347	110,485	131,434
Operating Segments | Aftermarket Segment
Segment Reporting Information
Operating profit	$ 28,900	$ 10,806	$ 48,996	$ 31,131