Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Non-cash investing and financing activities:
Fixed assets acquired with accounts payable or accrued liabilities	$ 43,147	$ 14,331
Issuance of promissory note in exchange for sale of equity method investment	0	54,154
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	19,384	21,186
Investing cash flows from finance leases	0	10,896
Financing cash flows from finance leases	0	45,773
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	44,915	26,395
Finance leases	$ 0	$ 51,064