Earnings per Share Impact on Diluted Shares of Conversion of TEUs (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Minimum [Member] Tangible Equity Units [Member]	Sep. 30, 2013 Middle [Member] Tangible Equity Units [Member]	Sep. 30, 2013 Maximum [Member] Tangible Equity Units [Member]	Oct. 02, 2015 Scenario, Forecast [Member] Minimum [Member] Tangible Equity Units [Member]	Oct. 02, 2015 Scenario, Forecast [Member] Middle [Member] Tangible Equity Units [Member]	Oct. 02, 2015 Scenario, Forecast [Member] Maximum [Member] Tangible Equity Units [Member]
Assumed Market Price of Class A Common Stock								$ 80.94	$ 73.00	$ 64.75
Tangible Equity Units Number Of Shares Upon Conversion Total					2,842	3,151	3,552
Weighted Average Diluted Shares Outstanding	56,738	41,682	56,637	43,471	56,738	57,047	57,448