Commitments and Contingencies (Details) - USD ($)					1 Months Ended
	Dec. 29, 2016	Sep. 30, 2015	Aug. 20, 2015	May 02, 2012	Aug. 31, 2017	Mar. 30, 2018	Sep. 29, 2017	Sep. 28, 2012
Loss Contingencies [Line Items]
Litigation amount	$ 4,700,000
UGL Infrastructure Pty Limited
Loss Contingencies [Line Items]
Percentage of ownership interest in joint venture								50.00%
Nui Phao Mining Company
Loss Contingencies [Line Items]
Damages sought		$ 167,000,000
Judicial Council Of California - Unpaid Fees
Loss Contingencies [Line Items]
Litigation amount				$ 4,700,000
Litigation contract amount			$ 4,700,000
Judicial Council Of California, Disgorged Fees
Loss Contingencies [Line Items]
Litigation amount				$ 18,300,000
Litigation contract amount			$ 18,300,000
General Electric and GE Electrical International Inc | Pending Litigation | Minimum
Loss Contingencies [Line Items]
Damages sought					$ 665,500,000.0
JKC Australia LNG Pty Limited | Pending Litigation
Loss Contingencies [Line Items]
Damages sought					1,700,000,000
Line of Credit
Loss Contingencies [Line Items]
Short-term debt						$ 449,200,000	$ 262,100,000
Surety Bond
Loss Contingencies [Line Items]
Short-term debt						$ 922,200,000	$ 57,400,000
CH2M HILL Companies, Ltd. | JKC Australia LNG Pty Limited | Pending Litigation
Loss Contingencies [Line Items]
Damages sought					$ 26,000,000