Long-Term Debt Long Term Debt (Term Loan B) (Details) (USD $)	2 Months Ended	3 Months Ended			0 Months Ended	3 Months Ended		0 Months Ended
	Dec. 31, 2011 Term Loan A [Member]	Sep. 30, 2014 Term Loan A [Member]	Sep. 30, 2013 Term Loan A [Member]	Nov. 09, 2011 Term Loan A [Member]	Jan. 16, 2014 Term Loan B [Member]	Sep. 30, 2014 Term Loan B [Member]	Sep. 30, 2014 LIBOR [Member] Term Loan A [Member]	Jan. 16, 2014 LIBOR [Member] Term Loan B [Member]
Debt Instrument [Line Items]
Credit agreement, maximum capacity				$ 600,000,000	$ 800,000,000
Term loan period, years	5 years				7 years
Term loan repayment as percentage of principal in year 1	1.25%				0.25%
Interest addition to floating rate					0.75%		2.50%	2.50%
Interest expense		$ 3,700,000	$ 3,500,000			$ 6,600,000