Contract Assets and Liabilities - Cost and Estimated Earnings Compared to Billings on Uncompleted Contracts (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Costs on uncompleted contracts	$ 1,635,361	$ 1,520,510
Estimated earnings to date on uncompleted contracts	158,966	146,459
Costs and estimated earnings to date on uncompleted contracts	1,794,327	1,666,969
Billings to date on uncompleted contracts	(1,829,626)	(1,690,175)
Net billings in excess of costs and estimated earnings on uncompleted contracts	$ (35,299)	$ (23,206)