Revenue - Summary of Asset Balances and Related Amortization Expense For Contract Costs (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Costs to Obtain a Contract [Member]
Capitalized Contract Cost [Line Items]
Beginning Balance	$ 232,583	$ 194,964
Capitalization of Costs	20,541	21,184
Amortization	(8,785)	(7,188)
Ending Balance	244,339	208,960
Costs to Fulfill a Contract [Member]
Capitalized Contract Cost [Line Items]
Beginning Balance	199,593	143,788
Capitalization of Costs	22,178	19,509
Amortization	(6,802)	(4,976)
Ending Balance	$ 214,969	$ 158,321