Schedule II - Consolidated Valuation and Qualifying Accounts (Detail) - Allowance for doubtful accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 2,890	$ 3,395	$ 2,566
Charged/(Credited) to Expense	2,452	2,314	1,785
Other Adjustments	(59)	14	208
Deductions	(1,493)	(2,833)	(1,164)
Balance at End of Period	$ 3,790	$ 2,890	$ 3,395