Commitments and Contingencies - Additional Information (Details) $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)
Commitments and Contingencies [Line Items]
Purchase commitment, due in next twelve months	$ 69.0
Purchase commitment due after twelve months	$ 7.3
Minimum
Commitments and Contingencies [Line Items]
Length of purchase commitments, (in days)	60 days
Maximum
Commitments and Contingencies [Line Items]
Length of purchase commitments, (in days)	120 days
Buildings And Equipment
Commitments and Contingencies [Line Items]
Lease future expiration date, year	2026
Total remaining lease obligations	$ 2.6