Contract Assets and Liabilities - Cost and Estimated Earnings Compared to Billings on Uncompleted Contracts (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Costs on uncompleted contracts	$ 1,337,906	$ 1,058,434
Estimated earnings to date on uncompleted contracts	132,934	110,430
Costs and estimated earnings to date on uncompleted contracts	1,470,840	1,168,864
Billings to date on uncompleted contracts	(1,485,721)	(1,179,560)
Net billings in excess of costs and estimated earnings on uncompleted contracts	$ (14,881)	$ (10,696)