Revenue - Contract Balances (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2022	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Contract assets	$ 68,245	$ 54,199
Contract liabilities	(66,582)	(42,433)
Net contract asset	1,663	11,766
Revenue recognized related to contract liabilities	36,000
Retention amounts included in accounts receivable	9,200	$ 9,600
Retained amount expected to be collected in the next twelve months	8,600
Retained amount expected to be collected	$ 600