Earnings per Share Offerings (Details) (USD $)	0 Months Ended				0 Months Ended
	Sep. 19, 2012 Tangible Equity Units [Member]	Sep. 20, 2012 Tangible Equity Units [Member]	Oct. 02, 2015 Scenario, Forecast [Member] Tangible Equity Units [Member] Maximum [Member]	Oct. 02, 2015 Scenario, Forecast [Member] Tangible Equity Units [Member] Minimum [Member]	Sep. 19, 2012 Class A common shares [Member]	Sep. 28, 2012 Class A common shares [Member]	Sep. 20, 2012 Class A common shares [Member]
Schedule of Stock Offering [Line Items]
Shares issued in public offering	2,300,000				3,791,004
Price per share in public offering							$ 64.75
Shares issued as a result of the underwriter's exercise of their over-allotment option	300,000				525,000
Stated par value per share		$ 100
Share Price			$ 64.75	$ 80.94		$ 66.86
Tangible Equity Units Number Of Shares Upon Conversion Per Unit			1.5444	1.2355