Non-Operating Income and Deductions (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Non-Operating Income and Deductions [Abstract]
Interest income	$ 3,900,000	$ 2,700,000	$ 2,900,000
Interest expense	(3,254,000)	(3,336,000)	(3,490,000)
Foreign exchange gains (losses)	(1,211,000)	324,000	(2,452,000)
Foreign currency translation loss upon liquidation			(2,300,000)
Foreign currency translation loss upon deconsolidation	(1,400,000)
Gain on sale of previously impaired assets		200,000
Gain (loss) on contract termination		800,000
Other income (deductions)	(600,000)	(100,000)	(800,000)
Non-operating income (deductions), net	$ (2,598,000)	$ 572,000	$ (6,087,000)