Derivative Financial Instruments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Agreement term		5 years
Aggregate notional amount		$ 300,000,000
Floor plan notes payable: non-trade	$ 1,293,200,000	$ 1,300,000,000	$ 1,293,200,000		$ 1,642,400,000
Fair value of derivative instruments	9,200,000		9,200,000
Amount of net losses expected to reclassify from AOCI into interest expense in earnings within the next twelve months	2,700,000		2,700,000
Amount reclassified from AOCI	$ 700,000		$ 1,100,000	$ 0