Interim Consolidated Financial Statements - Summary of Lease Balances (Detail) $ in Thousands	Sep. 30, 2019 USD ($)
Leases [Abstract]
Operating lease right-of-use assets	$ 71,093
Short term operating lease liabilities	$ 16,178
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent
Non-current operating lease liabilities	$ 63,829
Total operating lease liabilities	$ 80,007