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Segment Reporting (Schedule of Automotive and Other Segment Reporting) (Details) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Segment Reporting Information [Line Items] |  |  |  |
Revenue | $ 468,711,354 | $ 454,981,440 | $ 937,300,351 | $ 920,401,545
Income from operations | 127,904,966 | 126,683,004 | 249,501,298 | 255,198,337
Automotive Products |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 456,625,064 | 444,245,425 | 912,423,707 | 899,210,799
Income from operations | 124,295,223 | 123,758,195 | 241,247,925 | 248,720,353
Other |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 12,086,290 | 10,736,015 | 24,876,644 | 21,190,746
Income from operations | $ 3,609,743 | $ 2,924,809 | $ 8,253,373 | $ 6,477,984

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