Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 252	$ 489	$ 566
Additions Charged to Costs and Expenses	235	166	430
Additions Charged to Other Accounts	0	0	0
Deductions	128	403	507
Balance at End of Period	359	252	489
Valuation Allowance of Deferred Tax Assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	6,882	4,650	3,753
Additions Charged to Costs and Expenses	595	2,232	999
Additions Charged to Other Accounts	0	0	0
Deductions	0	0	102
Balance at End of Period	$ 7,477	$ 6,882	$ 4,650