Commitments and Contingencies - Future Minimum Payments for all Operating Lease Obligations and Sublease Rental Income (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Operating Leases
2018	$ 44,193
2019	41,386
2020	38,877
2021	36,942
2022	21,355
Thereafter	85,237
Total	267,990
Sublease Rental Income
2018	2,000
2019	2,164
2020	1,604
2021	1,556
2022	781
Thereafter	1,774
Total	$ 9,878