SCHEDULE II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		$ 2,826	$ 2,589	$ 2,692
Additions Charged to Operations		3,451	3,858	3,876
Net Deductions	[1]	2,780	3,621	3,979
Balance at End of Period		3,497	2,826	2,589
Deferred Tax Asset Valuation Allowance
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period		2,886	3,846	4,084
Additions Charged to Operations		489
Net Deductions	[2]		960	238
Balance at End of Period		$ 3,375	$ 2,886	$ 3,846

[1] Represents write-offs of accounts, net of recoveries.

[2] Represents current year releases credited to expenses and current year reductions due to decreases in net deferred tax assets.