Valuation and Qualifying Accounts and Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 2,378	$ 5,814	$ 2,946
Additions (reductions) to Costs and Expenses	15,126	12,321	9,948
Write offs	(10,748)	(15,757)	(7,080)
Balance at End of Period	6,756	2,378	5,814
Allowance for deferred tax assets
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	251	278	256
Additions (reductions) to Costs and Expenses	835	(27)	22
Write offs	0	0	0
Balance at End of Period	$ 1,086	$ 251	$ 278