Schedule II - Valuation and Qualifying Accounts (Detail) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 120	$ 120	$ 206
Additions (Recovery) to Bad Debt Expense	57	0	(85)
Charged to Other Accounts	0	0	0
Deductions	(89)	0	(1)
Balance at End of Period	$ 88	$ 120	$ 120