Share-Based Compensation (Tables)

6 Months Ended

Mar. 31, 2015

Stock-Based Compensation [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

Fair value is estimated at the grant date based on a Black-Scholes-Merton option-pricing model using the following weighted-average assumptions:

	Six Months Ended March 31, 2015
Expected stock price volatility	34%
Expected dividend yield	—%
Risk free interest rate	0.80%
Average expected life (in years)	2.88

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

The following is a summary of stock option activity for the six months ended March 31, 2015:

	Shares Available for Grant		Number of Options Outstanding		Weighted Average Price		Weighted Average Grant Date Fair Value		Weighted Average Remaining Term (in years)	Aggregate Intrinsic Value ($ millions)
Balances as of September 30, 2014	913,500		1,578,056		$	25.38	$	11.58	4.16	$	1.9
Granted	(91,000	)	91,000		$	20.54	$	4.31
Exercised			(281,095	)	$	11.06	$	5.84
Forfeited	—		(5,333	)	$	19.59	$	5.27
Expired	—		(45,359	)	$	27.92	$	12.08
Balances as of March 31, 2015	822,500		1,337,269		$	28.00	$	12.31	4.53	$	7.0
Exercisable as of March 31, 2015			390,636		$	36.17	$	13.32	1.37	$	2.1

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]

The following is a summary of restricted stock activity for the six months ended March 31, 2015:

	Shares Available for Grant		Number of Shares Outstanding		Weighted Average Grant Date Fair Value		Weighted Average Remaining Term (in years)	Aggregate Intrinsic Value ($ millions)
Balances as of September 30, 2014	1,096,325		229,851		$	20.03	1.79	$	4.0
Granted	(104,964	)	104,964		$	19.20
Vested			(93,467	)	$	21.73
Forfeited	328		(328	)	$	18.12
Balances as of March 31, 2015	991,689		241,020		$	19.01	2.41	$	7.2