Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2019
Current:
U.S. federal statutory income tax rate (as a percent)	21.00%	21.00%	21.00%
Federal	$ 5,200	$ 1,400	$ 4,800
State	1,200	900	100
Foreign	3,400	2,800	5,000
Total current	9,800	5,100	9,900
Deferred	8,400	500	(5,000)
Provision for income tax	18,200	5,600	4,900
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	13,500	6,400	18,700
Tax expense (benefits) from stock-based compensation	700	(2,100)	(2,700)
State income taxes, net of federal benefit and refunds	2,400	1,100	1,900
Change in valuation allowance for state deferred tax assets		(100)	(6,900)
Effective settlement of prior tax positions			(4,700)
Other	1,600	300	(1,400)
Provision for income tax	18,200	5,600	4,900
Income before provision for income taxes	64,500	30,400	89,000
Deferred tax assets:
Operating lease liabilities	20,700	24,900
Employee and retirement benefits	10,400	13,300
State net operating losses	6,800	9,400
Allowance for doubtful accounts	4,000	4,100
Credits and incentives	1,100	8,200
Other	1,500	5,000
Total deferred tax assets	44,500	64,900
Deferred tax liabilities:
Tangible and intangible assets	(31,900)	(35,000)
ROU operating lease assets	21,900	26,200
Other	(200)	(200)
Total deferred tax liabilities	(54,000)	(61,400)
Net deferred tax assets (liabilities)		3,500
Net deferred tax assets (liabilities)	$ (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		7,900
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	43,700	23,600	68,900
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	$ 20,800	$ 6,800	$ 20,100