Commitments and Contingencies (Details)	Sep. 20, 2018 subclass	Apr. 30, 2021 USD ($)
Loss Contingencies [Line Items]
Standby letters of credit		$ 149,200,000
Surety bonds		600,700,000
Bucio
Loss Contingencies [Line Items]
Loss contingency, number of certified subclasses | subclass	4
Energy Savings Contracts
Loss Contingencies [Line Items]
Guarantee obligation		206,500,000
Minimum
Loss Contingencies [Line Items]
Amount of reasonably possible loss		0
Maximum
Loss Contingencies [Line Items]
Amount of reasonably possible loss		8,000,000
Pending Litigation
Loss Contingencies [Line Items]
Loss contingency amount accrued for probable losses		14,600,000
Pending Litigation | Bucio
Loss Contingencies [Line Items]
Loss contingency amount accrued for probable losses		30,000,000
Amount of reasonably possible loss		$ 160,000,000