Earnings per Share Settlement of TEUs (Details) - Settlement of TEUs [Member] $ in Millions	3 Months Ended
	Dec. 31, 2015 USD ($) shares
Class A Common Stock, $0.01 par value, one vote per share; 180,000,000 shares authorized at September 30, 2015 and December 31, 2014; 66,081,310 and 65,632,309 shares issued and 53,352,916 and 52,938,267 shares outstanding (net of 12,728,394 and 12,694,042 shares in treasury) on September 30, 2015 and December 31, 2014, respectively
Subsequent Event [Line Items]
Stock issued upon settlement of prepaid stock purchase contract component of TEUs | shares	3,539,240
TEUs - amortizing note [Member]
Subsequent Event [Line Items]
Repayments of amortizing note component of TEUs	$ 2.8