Schedule II - Valuation and Qualifying Accounts and Reserves Supplemental Schedule (Detail) - Accounts Receivable Reserves - 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	$ 2,121	$ 2,040	$ 2,028
Charged to Costs and Expenses (Recovery)	795	1,653	530
Charged to Other Accounts	39	1	31
Deductions	(889)	(1,573)	(549)
Balance at End of Period	$ 2,066	$ 2,121	$ 2,040