Contract Assets and Liabilities - Cost and Estimated Earnings Compared to Billings on Uncompleted Contracts (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Costs on uncompleted contracts	$ 2,899,250	$ 2,224,511	$ 1,831,106
Estimated earnings to date on uncompleted contracts	393,665	271,719	194,760
Costs and estimated earnings to date on uncompleted contracts	3,292,915	2,496,230	2,025,866
Billings to date on uncompleted contracts	(3,376,875)	(2,590,329)	(2,077,475)
Net billings in excess of costs and estimated earnings on uncompleted contracts	$ (83,960)	$ (94,099)	$ (51,609)