Capital Stock - (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Capital Stock [Roll Forward]
Treasury Shares, Beginning Balance	(3,158,000)	(3,135,000)	(3,100,000)
Exercise of stock options	33,810	30,166	9,417
Treasury Shares, Ending Balance	(3,187,000)	(3,158,000)	(3,135,000)
Number of stock awards canceled	77,591	12,925	10,631
Common Stock
Capital Stock [Roll Forward]
Common Stock, Beginning Balance	34,084,000	33,952,000	33,835,000
Exercise of stock options	34,000	30,000	10,000
Restricted stock awards	101,000	102,000	107,000
Common Stock, Ending Balance	34,219,000	34,084,000	33,952,000
Dividends declared (in dollars per share)	0.05	0.05	0.05
Dividends paid (in dollars per share)	0.05	0.05	0.05
Class B Common Shares
Capital Stock [Roll Forward]
Common Stock, Beginning Balance	1,085,000	1,085,000	1,085,000
Exercise of stock options	0	0	0
Restricted stock awards	0	0	0
Common Stock, Ending Balance	1,085,000	1,085,000	1,085,000
Dividends declared (in dollars per share)	0.045	0.045	0.045
Dividends paid (in dollars per share)	0.045	0.045	0.045
Treasury Shares
Capital Stock [Roll Forward]
Exercise of stock options	0	0	(8,000)
Restricted stock awards	(29,000)	(23,000)	(27,000)