Schedule II - Valuation and Qualifying Accounts (Detail) - Valuation and Qualifying Accounts (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for Doubtful Accounts [Member]
Balance	$ 1,727	$ 1,310	$ 665
Charged to Costs and Expenses	322	1,125	3,031
Charged to Other Accounts		213
Deductions	(452)	(921)	(2,386)
Balance	1,597	1,727	1,310
Valuation Allowance of Deferred Tax Assets [Member]
Balance	401	412	605
Charged to Costs and Expenses	799		(193)
Deductions		(11)
Balance	$ 1,200	$ 401	$ 412