Revenue - Summary of Asset Balances and Related Amortization Expense For Contract Costs (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Costs to Obtain a Contract [Member]
Capitalized Contract Cost [Line Items]
Beginning Balance	$ 194,964	$ 158,989
Capitalization of Costs	21,184	19,387
Amortization	(7,188)	(5,721)
Ending Balance	208,960	172,655
Costs to Fulfill a Contract [Member]
Capitalized Contract Cost [Line Items]
Beginning Balance	143,788	101,756
Capitalization of Costs	19,509	15,005
Amortization	(4,976)	(3,470)
Ending Balance	$ 158,321	$ 113,291