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Inventories, Net - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Inventory Disclosure [Abstract] |  |  |
Lower of cost or net realizable value reserves | $ 9.7 | $ 8.5 |
Reduction in inventory cost for interest received from manufacturers | 10.7 | 9.7 |
Reduction in new vehicle cost of sales for interest assistance received related to vehicles sold | $ 49.1 | $ 47.3 | $ 48.9

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