Prepaid Expenses and Other Current Assets (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Restricted cash	$ 0	$ 4,674,000
Prepaid vehicle licenses	69,434,000	62,772,000
Prepaid operating taxes	16,461,000	14,320,000
Prepaid sales commission	23,842,000	13,599,000
Prepaid insurance	16,423,000	15,688,000
Start-up costs	9,463,000	8,001,000
Prepaid maintenance	10,903,000	6,171,000
Prepaid vehicles	12,814,000	947,000
Other	42,286,000	33,922,000
Total	$ 201,626,000	$ 160,094,000