Non-Operating Income and Deductions (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Non-Operating Income and Deductions [Abstract]
Interest income	$ 3,000,000	$ 3,200,000	$ 3,900,000
Interest expense	(3,263,000)	(3,221,000)	(3,254,000)
Foreign exchange losses	(2,109,000)	(1,348,000)	(1,211,000)
Foreign currency translation loss upon deconsolidation of a foreign entity	0	0	(1,400,000)
Other deductions	(800,000)	(1,600,000)	(600,000)
Non-operating deductions, net	$ (3,142,000)	$ (2,995,000)	$ (2,598,000)
Percentage of interest in the joint venture sold (in hundredths)	50.00%