Share-Based Payments (Details 3) (USD $)	9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Stock option disclosures
Cash proceeds from option exercised	$ 18,722,000	$ 23,080,000
Stock Options
Weighted average assumptions relating to the valuation of stock options
Expected life	5 years	5 years
Expected volatility (as a percent)	56.30%	58.40%
Risk-free interest rate (as a percent)	0.80%	1.10%
Dividend yield (as a percent)	0.00%	0.00%
Stock option disclosures
Period of zero-coupon U.S. Treasury notes	5 years
Weighted average fair value of the stock options issued (in dollars per share)	$ 11.29	$ 9.60
Total intrinsic value of options exercised	42,300,000
Cash proceeds from option exercised	18,700,000
Tax benefit realized for the tax deductions of stock option exercises	13,800,000
Total unrecognized compensation costs related to unvested stock option awards	$ 17,800,000
Weighted average period for recognition of unvested awards	2 years 4 months 24 days