Stock-Based Compensation (Tables)

12 Months Ended

Apr. 30, 2013

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of stock options and SSARs granted under the plan

The following table presents information about stock options and stock-settled stock appreciation rights (SSARs) granted under the Plan as of April 30, 2013, and for the year then ended:

	Number of Underlying Shares (in thousands)		Weighted Average Exercise Price per Award		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding at May 1, 2012	5,446		$	31.97
Granted	544		58.70
Exercised	(1,367	)	24.56
Forfeited or expired	(36	)	48.84
Outstanding at April 30, 2013	4,587		$	37.22	5.1	$	152
Exercisable at April 30, 2013	2,831		$	30.98	3.6	$	111

Assumptions used for fair value estimation

We estimated the fair values using the Black-Scholes pricing model with the following assumptions:

	2011		2012		2013
Risk-free interest rate	2.1	%	1.9	%	0.9	%
Expected volatility	23.7	%	23.6	%	22.9	%
Expected dividend yield	1.9	%	1.9	%	1.9	%
Expected term (years)	6		6		6.5

Summary of changes in outstanding RSUs and restricted stock

The following table summarizes the changes in the number of shares underlying these awards during 2013:

	Number of Underlying Shares (in thousands)		Weighted Average Fair Value at Grant Date
Nonvested at May 1, 2012	295		$	38.25
Granted	85		63.15
Adjusted for dividends or performance	12		42.86
Vested	(76	)	32.51
Forfeited	(2	)	56.70
Nonvested at April 30, 2013	314		$	46.41