Revenue - Contract Balances (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2023	Sep. 30, 2022
Revenue from Contract with Customer [Abstract]
Contract assets	$ 63,560	$ 88,351
Contract liabilities	(178,217)	(79,857)
Net contract asset (liability)	(114,657)	8,494
Revenue recognized related to contract liabilities	58,700
Retention amounts included in accounts receivable	6,600	$ 6,900
Retained amount expected to be collected in the next twelve months	6,400
Retained amount expected to be collected	$ 200