Schedule II - Valuation and Qualifying Accounts (Detail) - SEC Schedule, 12-09, Allowance, Credit Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 67	$ 71	$ 88
Additions (Recovery) to Bad Debt Expense	(12)	12	(17)
Charged to Other Accounts	43	0	0
Deductions	(55)	(16)	0
Balance at End of Period	$ 43	$ 67	$ 71