Schedule II VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for doubtful accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Start of Period			$ 50
Deductions			(50)
Balance at End of Period			0
Deferred income tax valuation allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Start of Period	12,793	12,654	12,925
Additions Charged to Costs and Expenses	75	350	846
Additions Charged/Credited to Other Accounts	38	96	115
Deductions	(3,513)	(307)	(1,232)
Balance at End of Period	$ 9,393	$ 12,793	$ 12,654