Revenues - Deferred Revenue Balances (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Revenue Disclosure [Abstract]
Deferred revenue, including long-term portion	$ 144,187	$ 114,416
Less: Deferred revenue, long-term portion, included in other liabilities	13,428	10,000
Deferred revenue, short-term portion	$ 130,759	$ 104,416