Schedule II - Valuation and Qualifying Accounts (Detail) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 1,882	$ 729	$ 443
Charged to (Recovered from) Costs and Expenses	(226)	1,189	592
Charged to Other Accounts	0	0	0
Deductions	(89)	(36)	(306)
Balance at End of Period	$ 1,567	$ 1,882	$ 729