Commitments and Contingencies - Future Minimum Lease Payments Due Under Non-Cancelable Operating Leases and Purchase Commitments by Year (Detail) $ in Thousands	Sep. 30, 2018 USD ($)
Future Minimum Lease Payments
October 1, 2018 - December 31, 2018	$ 180
2019	1,658
2020	48
2021	0
2022	0
2023	0
Thereafter	0
Total	1,886
Purchase Commitments
October 1, 2018 - December 31, 2018	17,958
2019	47,287
2020	46,141
2021	28,097
2022	25,069
2023	12,284
Thereafter	53,621
Total	$ 230,457

Operating Leases, Future Minimum Payments, Due After Six Years

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Operating Leases, Future Minimum Payments, Due in Six Years

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Purchase Obligation, Due after Sixth Year

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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