Consolidated Balance Sheets Parentheticals - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Class A Common Shares [Member]
Common Stock, par value per share	$ 0.01	$ 0.01
Common Stock, votes per share	1	1
Common Stock, shares authorized	180,000,000	180,000,000
Common Stock, shares issued	66,081,310	65,632,309
Common Stock, shares outstanding	53,352,916	52,938,267
Treasury Stock, shares	12,728,394	12,694,042
Class B Common Shares [Member]
Common Stock, par value per share	$ 0.01	$ 0.01
Common Stock, votes per share	10	10
Common Stock, shares authorized	30,000,000	30,000,000
Common Stock, shares issued	794,938	1,020,485
Common Stock, shares outstanding	794,938	1,020,485