Commitments And Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Mar. 31, 2018	Sep. 30, 2017	Aug. 31, 2017
Commitments And Contingencies [Abstract]
Accrued Insurance	$ 6,985		$ 6,204
Liability for Claims and Claims Adjustment Expense	244		218
Estimated cost of completion of bonded project	66,794
Insurance Related [Member]
Other Commitments [Line Items]
Letters of Credit Outstanding, Amount	5,900		5,985
Vendor Related [Member]
Other Commitments [Line Items]
Letters of Credit Outstanding, Amount	$ 508		$ 508
Capstone [Member]
Loss Contingencies [Line Items]
Loss Contingency Name Of Plaintiff	Capstone Building Corporation
Loss Contingency, Damages Sought, Value	$ 10,406
Loss Contingency Opinion Of Counsel	Following mediation in June and November 2017, the Company reached an agreement in late December 2017 to settle all claims brought against it.
Loss Contingency Accrual At Carrying Value	$ 700
Insurance Settlements Receivable Current	500
Loss Contingency Accrual Payments	$ 200
USAMRIID [Member]
Loss Contingencies [Line Items]
Loss Contingency Name Of Plaintiff	IES Commercial, Inc.
Loss Contingency Opinion Of Counsel	Given the uncertainty litigation poses, the Company has not recorded any recovery in connection with this claim. There can be no assurance that the Company will prevail in this litigation matter or that, if the Company does prevail, it will receive an amount substantially similar to the amount sought or not receive a significantly lower award.
Unbilled Change Orders				$ 21,000
Contract Revenue Earned To Date	$ 61,146
USAMRIID [Member] | Scenario Forecast [Member]
Loss Contingencies [Line Items]
Unbilled Change Orders		$ 4,500