Segment Reporting (Schedule Of Automotive And Other Segment Reporting) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Revenue	$ 379,258,477	$ 338,436,964	$ 748,195,932	$ 674,176,308
Income from operations	108,132,830	99,835,438	215,841,336	197,012,984
Automotive Products
Segment Reporting Information [Line Items]
Revenue	370,504,300	329,557,679	731,119,589	655,921,786
Income from operations	105,242,465	96,849,968	210,050,524	190,294,435
Other
Segment Reporting Information [Line Items]
Revenue	8,754,177	8,879,285	17,076,343	18,254,522
Income from operations	$ 2,890,365	$ 2,985,470	$ 5,790,812	$ 6,718,549