Segment Reporting (Schedule Of Automotive And Other Segment Reporting) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenue	$ 429,643,276	$ 389,829,139	$ 1,259,011,840	$ 1,138,025,071
Income from operations	134,212,281	116,262,620	383,806,992	332,103,956
Automotive Products
Segment Reporting Information [Line Items]
Revenue	419,793,577	379,889,957	1,228,165,639	1,111,009,546
Income from operations	130,567,201	112,238,938	372,119,627	322,289,461
Other
Segment Reporting Information [Line Items]
Revenue	9,849,699	9,939,182	30,846,201	27,015,525
Income from operations	$ 3,645,080	$ 4,023,682	$ 11,687,365	$ 9,814,495