Consolidated Balance Sheets Parentheticals - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
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	70,018,069	69,674,185
Common Stock, shares outstanding	57,244,493	56,945,384
Treasury Stock, shares	12,773,576	12,728,801
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	793,138	793,138
Common Stock, shares outstanding	793,138	793,138