Segment Reporting (Schedule Of Automotive And Other Segment Reporting) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenue	$ 465,420,105	$ 453,535,250
Income from operations	128,515,333	134,427,120
Automotive Products
Segment Reporting Information [Line Items]
Revenue	454,965,374	445,652,575
Income from operations	124,962,159	132,504,957
Other
Segment Reporting Information [Line Items]
Revenue	10,454,731	7,882,675
Income from operations	$ 3,553,174	$ 1,922,163