Stock-Based Compensation (Tables)

6 Months Ended

Mar. 31, 2012

Stock-Based Compensation

Summary of compensation cost for stock-based payment arrangements recognized in general and administrative expense

	Three Months Ended				Six Months Ended
	March 31,				March 31,
	2012		2011		2012		2011
Compensation expense
Stock options	$	2,543	$	1,698	$	5,031	$	3,813
Restricted stock	2,293		1,259		3,727		2,331
	$	4,836	$	2,957	$	8,758	$	6,144

Summary of weighted-average assumptions utilized in determining the fair value of options granted

	2012		2011
Risk-free interest rate	1.0	%	1.9	%
Expected stock volatility	53.3	%	51.6	%
Dividend yield	0.4	%	0.5	%
Expected term (in years)	5.5		5.5

Summary of stock option activity

	Three Months Ended March 31, 2012
					Weighted-
			Weighted-		Average	Aggregate
			Average		Remaining	Intrinsic
	Shares		Exercise		Contractual Term	Value
Options	(in thousands)		Price		(in years)	(in millions)
Outstanding at January 1, 2012	4,814		$	29.45
Granted	—		—
Exercised	(75	)	21.59
Forfeited/Expired	—		—
Outstanding at March 31, 2012	4,739		$	29.58	5.3	$	118.1
Vested and expected to vest at March 31, 2012	4,681		$	28.94	5.3	$	117.1
Exercisable at March 31, 2012	3,606		$	24.63	4.3	$	105.8

	Six Months Ended March 31, 2012
			Weighted-
			Average
	Shares		Exercise
Options	(in thousands)		Price
Outstanding at October 1, 2011	4,589		$	25.84
Granted	453		59.76
Exercised	(280	)	16.61
Forfeited/Expired	(23	)	36.10
Outstanding at March 31, 2012	4,739		$	29.58

Summary of restricted stock awards and changes in restricted stock outstanding

	Six Months Ended
	March 31, 2012
			Weighted-
			Average
	Shares		Grant-Date
Restricted Stock Awards	(in thousands)		Fair Value
Unvested at October 1, 2011	323		$	42.38
Granted	244		59.76
Vested (1)	(119	)	40.21
Forfeited	(7	)	41.93
Unvested at March 31, 2012	441		$	52.59

(1)The number of restricted stock awards vested includes shares that we withheld on behalf of our employees to satisfy the statutory tax withholding requirements.