Revenue from Contracts with Customers - Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable, net of allowance for expected credit losses ($4,622 and $4,318, respectively)	$ 137,578	$ 119,877
Contract with Customer, Asset, after Allowance for Credit Loss, Current [Abstract]
Contract assets	25,800	15,300
Contract with Customer, Liability [Abstract]
Current contract liabilities	30,700	25,724
Contract liabilities	30,700	$ 25,700
Revenue recognized	$ 18,200