Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		72 Months Ended	93 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Mar. 31, 2019
Commitments and Contingencies [Line Items]
Purchase commitment, due in next twelve months	$ 54,000				$ 54,000
Revenue from contract with customer	90,516			$ 99,705	$ 277,624	$ 290,783
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
Government Contract
Commitments and Contingencies [Line Items]
Charges to income from price adjustment clauses							$ 4,800
GSA matter and imputed interest	400	$ 100	$ 500
Total estimated liability from price adjustment clauses	11,700		$ 5,300		$ 11,700			$ 5,300
Reduction in sales, adjustment	5,800
Estimated aggregate overcharge in contracts								$ 10,600
Other Expense | Government Contract
Commitments and Contingencies [Line Items]
Total estimated liability from price adjustment clauses	$ 6,200				$ 6,200