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 at Beginning of Period	$ 2,314	$ 1,051	$ 1,092
Charged to Costs and Expenses	140	1,853	746
Charged to Other Accounts	0	0	0
Deductions	(390)	(590)	(787)
Balance at End of Period	2,064	2,314	1,051
Valuation Allowance of Deferred Tax Assets [Member]
Balance at Beginning of Period	4,620	4,871	6,462
Charged to Costs and Expenses	4	198	(922)
Charged to Other Accounts	0	0	0
Deductions	(1,467)	(449)	(669)
Balance at End of Period	$ 3,157	$ 4,620	$ 4,871