Commitments and Contingencies - Narrative (Details)							9 Months Ended	48 Months Ended
	Dec. 04, 2018 plaintiff	Sep. 20, 2018 subclass	Mar. 20, 2018 collective_bargaining_arrangement	Jan. 26, 2018 plaintiff	Nov. 03, 2017 USD ($)	Feb. 07, 2017 plaintiff	Oct. 31, 2017 USD ($) plaintiff	Oct. 24, 2018	Oct. 31, 2018 USD ($)
Loss Contingencies [Line Items]
Letters of credit									$ 152,900,000
Surety bonds									475,300,000
Surety bonds with future effective date									$ 1,800,000
Subsidiary ownership interest percentage									33.00%
Loss contingency amount accrued for probable losses									$ 12,600,000
Number of collective bargaining arrangements | collective_bargaining_arrangement			3
Minimum
Loss Contingencies [Line Items]
Subsidiary ownership interest percentage									20.00%
Estimate of reasonably possible loss									$ 0
Maximum
Loss Contingencies [Line Items]
Subsidiary ownership interest percentage									50.00%
Estimate of reasonably possible loss									$ 4,000,000
Hussein And Isse
Loss Contingencies [Line Items]
Loss contingency amount accrued for probable losses									3,800,000
Settlement amount					$ 8,300,000
Hussein Opt-Out Members
Loss Contingencies [Line Items]
Loss contingency amount accrued for probable losses									900,000
Castro
Loss Contingencies [Line Items]
Loss contingency amount accrued for probable losses									5,400,000
Number of plaintiffs | plaintiff				3
Occurrence period after compliant								4 years
Bucio
Loss Contingencies [Line Items]
Number of certified subclasses | subclass		4
Isse
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff						60	220
Settlement amount					$ 4,500,000
Energy Savings Contracts
Loss Contingencies [Line Items]
Guarantee obligation							$ 157,900,000		171,700,000
Performance Guarantee | Joint Venture
Loss Contingencies [Line Items]
Total guarantee									$ 35,000,000.0
Subsequent Event | Hussein And Isse
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff	386
Subsequent Event | Hussein Opt-Out Members
Loss Contingencies [Line Items]
Number of opt-out members | plaintiff	78