Stock-Based Compensation (Details) (USD $)	12 Months Ended							0 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2012 The Purchase Plan [Member]	Sep. 30, 2011 The Purchase Plan [Member]	Sep. 30, 2010 The Purchase Plan [Member]	Jan. 25, 2010 The Purchase Plan [Member]	Jan. 25, 2010 The Omnibus Plan [Member]	Dec. 04, 2009 The Omnibus Plan [Member]	Sep. 30, 2012 The Stock Option Plan and Non-Officer Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period										4 years
Expiration period										10 years
Number of shares authorized									5,750,000
Number of additional shares authorized								2,500,000
Proceeds from stock option plan transactions	$ 1,072,000	$ 2,853,000	$ 1,672,000
Excess tax benefits from stock-based compensation	(198,000)	(796,000)	(47,000)
Number of continuous days of service				90 days
Number of hours per week employed				20 hours
Discount from market price				85.00%
Offering period				3 months
Number of additional shares authorized							250,000
Number of shares authorized							2,000,000
Employee contributions				1,000,000	1,000,000	900,000
Common shares issued to employees				115,477	112,285	124,087
Shares available for future issuance				199,680
Total intrinsic value of all options exercised	700,000	2,400,000	600,000
Forfeiture rate	2.00%
Total unrecognized compensation cost	6,100,000
Weighted average period, unrecognized compensation cost	2 years 6 months
Total fair value of shares vested	$ 3,000,000	$ 3,700,000	$ 2,900,000