Schedule II - Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 551	$ 519	$ 141
Charged to Costs and Expenses	1,381	33	379
Charged to Other Accounts	0	0	0
Deductions	(531)	(3)	(4)
Other	(27)	2	3
Balance at End of Period	1,374	551	519
Valuation Allowance Against Gross Deferred Income Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	2,639	2,887	3,042
Charged to Costs and Expenses	0	0	0
Charged to Other Accounts	721	35	11
Deductions	(33)	(156)	(132)
Other	(73)	(127)	(34)
Balance at End of Period	$ 3,254	$ 2,639	$ 2,887