Schedule II Valuation of Qualifying Accounts and Reserves (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Valuation and Qualifying Accounts Disclosure
Valuation Allowances and Reserves, Balance Beginning of Period	$ 775	$ 775	$ 775	$ 775
Valuation Allowances and Reserves, Charged to Cost and Expense	83	3	129	192
Valuation Allowances and Reserves, Charged to Other Accounts	0	0	0	0
Valuation Allowances and Reserves, Deductions	67	3	129	192
Valuation Allowances and Reserves, Balance End of Period	$ 791	$ 775	$ 775	$ 775