Segment Reporting (Schedule Of Automotive And Other Segment Reporting) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Revenue	$ 389,829,139	$ 350,913,912	$ 1,138,025,071	$ 1,025,090,220
Income from operations	116,262,620	103,205,827	332,103,956	300,218,811
Automotive Products
Segment Reporting Information [Line Items]
Revenue	379,889,957	341,786,404	1,111,009,546	997,708,190
Income from operations	112,238,938	100,053,622	322,289,461	290,348,056
Other
Segment Reporting Information [Line Items]
Revenue	9,939,182	9,127,508	27,015,525	27,382,030
Income from operations	$ 4,023,682	$ 3,152,205	$ 9,814,495	$ 9,870,755