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
Movement in valuation and qualifying accounts
Balance at Beginning of Year	$ 3,645	$ 5,094	$ 9,217
Additions Charged to Expenses	1,726	1,476	1,737
Charge-Offs	1,170	2,917	5,849
Other	2	(8)	(11)
Balance at End of Year	4,203	3,645	5,094
Allowance for other non-trade receivables
Movement in valuation and qualifying accounts
Balance at Beginning of Year		118	617
Charge-Offs		118	499
Balance at End of Year			118
Reserve for inventory valuation
Movement in valuation and qualifying accounts
Balance at Beginning of Year	8,297	8,437	6,834
Additions Charged to Expenses	1,515	2,210	3,030
Charge-Offs	2,057	1,911	1,981
Other	(12)	(439)	554
Balance at End of Year	7,743	8,297	8,437
Valuation allowance for deferred income tax assets
Movement in valuation and qualifying accounts
Balance at Beginning of Year	9,378	8,890	9,241
Additions Charged to Expenses	219	(106)	(467)
Other	(143)	594	116
Balance at End of Year	$ 9,454	$ 9,378	$ 8,890