Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2020
Current:
U.S. federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Federal	$ 11,000	$ 5,200	$ 1,400
State	2,600	1,200	900
Foreign	4,300	3,400	2,800
Total current	17,900	9,800	5,100
Deferred	8,700	8,400	500
Provision for income tax	26,600	18,200	5,600
Reasons for difference between the provision for income taxes on pre-tax income from the amount computed by applying the U.S. federal statutory tax rate
Provision for income tax at the federal statutory rate	22,100	13,500	6,400
Tax expense (benefits) from stock-based compensation	(2,100)	700	(2,100)
State income taxes, net of federal benefit and refunds	5,200	2,400	1,100
Change in valuation allowance for state deferred tax assets			(100)
Other	1,400	1,600	300
Provision for income tax	26,600	18,200	5,600
Income before provision for income taxes	105,100	64,500	30,400
Deferred tax assets:
Operating lease liabilities	21,000	20,700
State net operating losses	8,000	6,800
Employee and retirement benefits	7,600	10,400
Allowance for credit losses		4,000
Other	1,900	2,600
Total deferred tax assets	38,500	44,500
Deferred tax liabilities:
Tangible and intangible assets	(33,600)	(31,900)
ROU operating lease assets	(22,100)	(21,900)
Other	(2,800)	(200)
Total deferred tax liabilities	(58,500)	(54,000)
Net deferred tax liabilities	$ (20,000)	(9,500)
Minimum
Deferred tax liabilities:
Period for net operating losses carry forward (in years)	5 years
Maximum
Deferred tax liabilities:
Period for net operating losses carry forward (in years)	20 years
Accrued Liabilities
Deferred tax liabilities:
Income tax payable		700
Prepaid expenses and other current assets
Deferred tax liabilities:
Income tax receivable	$ 2,700
Domestic
Reasons for difference between the provision for income taxes on pre-tax income from the amount computed by applying the U.S. federal statutory tax rate
Income before provision for income taxes	77,100	43,700	23,600
Foreign
Reasons for difference between the provision for income taxes on pre-tax income from the amount computed by applying the U.S. federal statutory tax rate
Income before provision for income taxes	$ 28,000	$ 20,800	$ 6,800