Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Deferred tax assets:
Accrued liabilities and reserves	$ 30,932	$ 29,583
Workers compensation	9,922	9,000
Operating and finance lease obligations	46,693	9,186
Asset retirement obligations	7,361	6,294
Deferred compensation	3,540	4,221
Equity compensation	9,567	9,131
State net operating losses & tax credits	4,021	928
Other	3,548	3,068
Total gross deferred tax assets	115,584	71,411
Less valuation allowance	250	0
Total net deferred tax assets	115,334	71,411
Deferred tax liabilities:
Property and equipment depreciation	(597,740)	(484,065)
Goodwill	(34,869)	(27,047)
Other	(3,197)	(20)
Total gross deferred tax liabilities	(635,806)	(511,132)
Net deferred tax liability	$ (520,472)	$ (439,721)