Commitment and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2018	Dec. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Jan. 31, 2017
Commitments And Contingencies [Line Items]
Unemployment insurance assessment					$ 9,500,000
Fines for insufficient reporting of license plate	$ 28,000,000
Loss contingency, agreement amount		$ 3,500,000
Minimum
Commitments And Contingencies [Line Items]
Contractual obligation			$ 300,000,000	$ 150,000,000
Purchase obligation, 2019			80,000,000
Purchase obligation, 2020			80,000,000
Purchase obligation, 2021			$ 80,000,000