Equity (Details) $ / shares in Units, $ in Millions	12 Months Ended
	May 31, 2024 USD ($) item $ / shares shares	May 31, 2023 USD ($) $ / shares shares	May 31, 2022 USD ($) $ / shares shares
Stock options, additional disclosures
Weighted-average remaining term (in years) for options outstanding	6 years 4 months 24 days	6 years 2 months 12 days	6 years 8 months 12 days
Weighted-average remaining term (in years) for options exercisable	5 years 6 months	5 years 2 months 12 days	5 years 8 months 12 days
2013 Stock Plan
Stock-Based Compensation
Total number of shares granted since inception	6,291,628
Shares available for future grant	2,268,156
Employee Stock Option
Stock-Based Compensation
Expiration term	10 years
First number of equal annual increments in which stock options are exercisable | item	3
Commencement period after the date of grant for annual increments of stock options becoming exercisable	1 year
Weighted average fair value of stock options granted (in dollars per share) | $ / shares	$ 25.31	$ 17.61	$ 13.42
Assumptions used in the Black-Scholes option pricing models to estimate the fair value of each stock option grant
Risk-free interest rate	4.10%	3.10%	0.80%
Expected volatility of common stock	42.30%	42.20%	41.60%
Dividend yield	0.00%	0.00%	0.80%
Expected option term in years	5 years 1 month 6 days	5 years 2 months 12 days	5 years 3 months 18 days
Shares
Outstanding at beginning of year (in shares)	1,573,000	2,045,000	2,612,000
Granted (in shares)	141,545	221,900	144,815
Exercised (in shares)	(706,000)	(631,000)	(686,000)
Cancelled (in shares)	(5,000)	(63,000)	(26,000)
Outstanding at end of year (in shares)	1,004,000	1,573,000	2,045,000
Options exercisable at end of year (in shares)	696,000	1,018,000	1,189,000
Weighted Average Exercise Price
Outstanding at beginning of year (in dollars per share) | $ / shares	$ 33.24	$ 29.86	$ 28.34
Exercise price (in dollars per share) | $ / shares	58.27	41.88	37.84
Exercised (in dollars per share) | $ / shares	30.67	25.31	25.53
Cancelled (in dollars per share) | $ / shares	48.40	33.25	36.17
Outstanding at end of year (in dollars per share) | $ / shares	38.49	33.24	29.86
Options exercisable at end of year (in dollars per share) | $ / shares	$ 33.95	$ 35.09	$ 33.57
Stock options, additional disclosures
Total fair value of stock options vested | $	$ 3.3	$ 3.6	$ 4.3
Total intrinsic value of stock options exercised | $	22.5	15.5	14.4
Aggregate intrinsic value of options outstanding | $	32.7	26.6
Unearned compensation not yet recognized | $	$ 3.7
Average remaining expensed period of unearned compensation	1 year 8 months 12 days
Employee Stock Option | Selling, general and administrative expenses
Stock options, additional disclosures
Compensation expense | $	$ 3.0	$ 3.5	$ 3.8
Restricted stock
Stock-Based Compensation
Granted (in shares)	192,000
Stock options, additional disclosures
Unearned compensation not yet recognized | $	$ 12.9
Average remaining expensed period of unearned compensation	1 year 6 months
Restricted stock | Minimum
Stock-Based Compensation
Vesting period	1 year
Restricted stock | Maximum
Stock-Based Compensation
Vesting period	3 years
Performance Shares
Stock-Based Compensation
Vesting period	3 years