Commitments and Contingencies (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Loss Contingencies [Line Items]
Loss Contingency, Discounted Amount of Insurance-related Assessment Liability	$ 6,254	$ 6,683
Liability for Claims and Claims Adjustment Expense	36	$ 90
Letters of Credit Outstanding, Amount	5,664
Estimated cost of completion of bonded projects	92,856
Insurance Related [Member]
Loss Contingencies [Line Items]
Letters of Credit Outstanding, Amount	5,464
Vendor Related [Member]
Loss Contingencies [Line Items]
Letters of Credit Outstanding, Amount	$ 200