Schedule II - Valuation Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounts receivable, allowance for doubtful accounts
Valuation accounts
Balance at Beginning of Period	$ 477	$ 423	$ 467
Additions Charged (Credited) to Expense	503	350	(35)
Net (Deductions) Recoveries		(296)	(9)
Balance at End of Period	980	477	423
Notes receivable, allowance for doubtful accounts
Valuation accounts
Balance at Beginning of Period	840
Additions Charged (Credited) to Expense		940
Net (Deductions) Recoveries	(186)	(100)
Balance at End of Period	$ 654	$ 840