Capital Stock and Share Based Compensation Plans - Narrative (Details) (USD $)	12 Months Ended							24 Months Ended		1 Months Ended	24 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2013 common_share director	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Stock Options Common stock, Class A Maximum	Dec. 31, 2013 Restricted Stock and Restricted Stock Units Minimum	Dec. 31, 2013 Restricted Stock and Restricted Stock Units Maximum	Dec. 31, 2013 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2012 First Repurchase Plan Minimum	Sep. 30, 2012 First Repurchase Plan Maximum	Oct. 31, 2010 First Repurchase Plan Common stock, Class A	Sep. 30, 2012 First Repurchase Plan Common stock, Class A	Dec. 31, 2013 Second Share Repurchase Plan Minimum	Dec. 31, 2013 Second Share Repurchase Plan Maximum	Nov. 30, 2012 Second Share Repurchase Plan Common stock, Class A	Dec. 31, 2013 Second Share Repurchase Plan Common stock, Class A
Class of Stock [Line Items]
Classes of common shares	2
Minimum number of directors up for election to entitle shareholders to vote	3
Minumum percent of directors up for election to entitle shareholders to vote	33.33%
Stock repurchase program, authorized amount										$ 75,000,000				$ 100,000,000
Stock repurchased during period, value	74,199,000	23,564,000	51,383,000								75,000,000				74,000,000
Range of price of shares repurchased								$ 6.55	$ 11.33			$ 10.83	$ 19.97
Number of shares available for future stock compensation grants	4,500,000.0
Purchase price of stock options granted, percent of fair market value				100.00%
Vesting period of stock options					3 years	4 years
Total unrecognized compensation cost related to restricted stock, RSUs and performance shares	$ 6,600,000
Weighted-average period of recognition, years							1 year 7 months