Share-Based Payments (Tables)

12 Months Ended

Apr. 30, 2018

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

Weighted average Black-Scholes assumptions for stock options granted

The fair value of each stock option is estimated on the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions for stock options granted in 2016:



	2016
Expected volatility (%)	20.7	%
Dividend Yield (%)	2.3	%
Risk-free interest rate (%)	1.9	%
Expected life of stock option (years)	5.9

Summary of the Company's stock option activity and related information

The following table is a summary of our stock option activity.



	Number of Stock Options	Weighted-Average Exercise Price
Outstanding at May 1, 2017	915,000		$	113.07
Exercised	35,002		111.86
Cancelled	56,666		111.86
Outstanding at April 30, 2018	823,332		$	113.20
Exercisable at April 30, 2018	270,006		$	113.22

Summary of restricted shares, deferred shares, deferred stock units, and performance units

The following table is a summary of our restricted shares, deferred stock units, and performance units.



	Restricted Shares and Deferred Stock Units		Weighted- Average Grant Date Fair Value			Performance Units		Weighted- Average Conversion Date Fair Value
Outstanding at May 1, 2017	573,405			$	115.88	73,701			$	126.80
Granted	136,127			126.80		84,051			103.86
Converted	73,701			126.80		(73,701	)		126.80
Vested	(161,581	)		106.04		—			—
Forfeited	(79,294	)		120.27		—			—
Outstanding at April 30, 2018	542,358			$	122.39	84,051			$	103.86

Weighted-average grant date fair values of the equity awards

The following table summarizes the weighted-average fair values of the equity awards granted.



Year Ended April 30,	Restricted Shares and Deferred Stock Units	Weighted- Average Grant Date Fair Value			Performance Units	Weighted- Average Conversion Date Fair Value
2018	136,127		$	126.80	84,051		$	103.86
2017	180,997		133.92		73,701		126.80
2016	97,922		113.57		121,936		132.46