Share-based Compensation - Summary of Share-Based Award Activity for Stock Options and Stock Appreciation Rights (Details)	12 Months Ended
	Aug. 31, 2019 $ / shares shares
Number of Shares
Outstanding at beginning of period (in shares) | shares	585,926
Granted | shares	104,174
Exercised | shares	(108,450)
Forfeited | shares	(11,400)
Outstanding at end of period (in shares) | shares	570,250
Exercisable at end of period (in shares) | shares	137,063
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 110.86
Granted | $ / shares	150.64
Exercised | $ / shares	88.60
Forfeited | $ / shares	127.22
Outstanding at end of period (in dollars per share) | $ / shares	122.03
Exercisable at end of period (in dollars per share) | $ / shares	$ 102.84