Commitments and Contingencies (Details) - USD ($)	3 Months Ended
	Dec. 31, 2021	Jan. 31, 2022
Guarantee Obligations [Line Items]
Additional bonding capacity	$ 455,600,000
Cash collateral required for guarantees, period (greater than)	2 years
Facility Agreement | Powell (UK) Limited
Guarantee Obligations [Line Items]
Guarantee liability	$ 3,300,000
Revolving credit facility	9,500,000
Amount of credit facility remaining borrowing capacity	6,200,000
Facility Agreement | Powell (UK) Limited | Subsequent Event
Guarantee Obligations [Line Items]
Revolving credit facility		$ 6,800,000
Surety Bonds
Guarantee Obligations [Line Items]
Guarantee liability	144,400,000
U.S. Revolver | Amended and Restated Credit Agreement
Guarantee Obligations [Line Items]
Revolving credit facility	75,000,000
Amount of credit facility remaining borrowing capacity	43,800,000
U.S. Revolver | Financial Standby Letter of Credit | Amended and Restated Credit Agreement
Guarantee Obligations [Line Items]
Guarantee liability	$ 31,200,000