Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Valuation and Qualifying Accounts Disclosure [Line Items]
Provisions for doubtful accounts	$ 938	$ 404	$ 1,757
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	4,101	4,503	4,418
Additions - Charges to Costs and Expenses		404	1,757
Deductions - Returns and Write-Offs	239	806	1,672
Balance at End of Year	$ 4,800	$ 4,101	$ 4,503