Share-Based Payments (Details 3) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Stock option disclosures
Cash received from option exercised	$ 26,663,000	$ 25,493,000	$ 28,020,000
Stock Options
Weighted average assumptions relating to the valuation of stock options
Expected life	5 years	5 years	5 years
Expected volatility (as a percent)	47.30%	56.30%	58.40%
Risk-free interest rate (as a percent)	1.30%	0.80%	1.10%
Dividend yield (as a percent)	0.00%	0.00%	0.00%
Stock option disclosures
Weighted average fair value of the stock options issued (in dollars per share)	$ 11.08	$ 11.29	$ 9.60
Total fair value of stock options	19,500,000	12,700,000	10,400,000
Total intrinsic value of options exercised	50,300,000	55,400,000	53,200,000
Cash received from option exercised	26,700,000	25,500,000	28,000,000
Tax benefit realized for the tax deductions of stock option exercises	18,300,000	18,700,000	18,900,000
Total unrecognized compensation costs related to unvested stock option awards	$ 13,500,000
Weighted average period for recognition of unvested awards	2 years 3 months 18 days