Stockholders' Equity (Details) (USD $)					12 Months Ended
	Sep. 30, 2013	Sep. 30, 2010	Sep. 30, 2009	Dec. 02, 2005	Sep. 30, 2013 Minimum	Sep. 30, 2013 Maximum	Sep. 30, 2013 Options granted to employees Performance-based	Sep. 30, 2013 Options granted to employees Performance-based Minimum	Sep. 30, 2013 Options granted to employees Performance-based Maximum	Sep. 30, 2013 Employee and director options	Sep. 30, 2012 Employee and director options	Sep. 30, 2011 Employee and director options	Sep. 30, 2010 Employee and director options	Sep. 30, 2013 Employee and director options Minimum	Sep. 30, 2012 Employee and director options Minimum	Sep. 30, 2011 Employee and director options Minimum	Sep. 30, 2010 Employee and director options Minimum	Sep. 30, 2013 Employee and director options Maximum	Sep. 30, 2012 Employee and director options Maximum	Sep. 30, 2011 Employee and director options Maximum	Sep. 30, 2010 Employee and director options Maximum	Sep. 30, 2013 Restricted shares	Sep. 30, 2012 Restricted shares	Sep. 30, 2011 Restricted shares	Sep. 30, 2010 Restricted shares	Sep. 30, 2013 Restricted shares Minimum	Sep. 30, 2012 Restricted shares Minimum	Sep. 30, 2011 Restricted shares Minimum	Sep. 30, 2010 Restricted shares Minimum	Sep. 30, 2013 Restricted shares Maximum	Sep. 30, 2012 Restricted shares Maximum	Sep. 30, 2011 Restricted shares Maximum	Sep. 30, 2010 Restricted shares Maximum	Sep. 30, 2013 Restricted shares Performance-based Non-employee	Sep. 30, 2012 Restricted shares Performance-based Non-employee	Sep. 30, 2013 Options or stock appreciation rights Maximum	Sep. 30, 2013 Other than options or stock appreciation rights Maximum	Sep. 30, 2013 Incentive stock options Minimum	Sep. 30, 2013 Incentive stock options Maximum	Sep. 30, 2013 Incentive stock options Holder of at least 10% of common stock Minimum
2006 Omnibus Long-Term Incentive Plan (the 2006 Plan)
Actual payout as a percent of employee target payout, based upon the entity's actual performance during the previous twelve months								0.00%	100.00%
Shares available for issuance				10,000,000
Remaining shares reserved for issuance	1,819,050	3,986,513	5,189,996
Options granted (in shares)										171,994	181,783	321,072	624,566
Options granted, exercise prices (in dollars per share)										$ 35.76	$ 34.42			$ 29.47	$ 31.37	$ 14.30	$ 9.05	$ 46.72	$ 42.31	$ 17.02	$ 13.96
Options forfeited (in shares)										32,244	78,148	73,591	75,467
Restricted shares granted (in shares)																						997,857	633,647	736,340	699,410									335,000	100,000
Restricted shares granted, exercise price (in dollars per share)																						$ 36.97	$ 34.05			$ 29.47	$ 31.37	$ 12.88	$ 9.05	$ 42.47	$ 52.55	$ 25.52	$ 13.96
Restricted shares forfeited (in shares)																						403,083	138,052	150,112	45,026									281,500
Number of shares awarded per person per year																																				1,000,000	700,000
Shares and options vesting period					1 year	4 years	12 months
Exercise price of stock option as a percentage of the fair market value of the common stock on the date of grant																																						100.00%		110.00%
Term of stock option																																							10 years