Revenue - Summary of Asset Balances and Related Amortization Expense For Contract Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Costs to Obtain a Contract [Member]
Capitalized Contract Cost [Line Items]
Beginning Balance	$ 244,339	$ 208,960	$ 232,583	$ 194,964
Capitalization of Costs	13,701	7,982	34,242	29,166
Amortization	(9,132)	(7,480)	(17,917)	(14,668)
Ending Balance	248,908	209,462	248,908	209,462
Costs to Fulfill a Contract [Member]
Capitalized Contract Cost [Line Items]
Beginning Balance	214,969	158,321	199,593	143,788
Capitalization of Costs	21,934	19,071	44,112	38,580
Amortization	(7,391)	(5,451)	(14,193)	(10,427)
Ending Balance	$ 229,512	$ 171,941	$ 229,512	$ 171,941