Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Payables and Accruals [Abstract]
Salaries, wages and other benefits	$ 67,648	$ 67,766
Provision for litigation	19,439	2,580
Obligation under operating leases	13,293	12,767
Obligation under finance leases	12,097	11,362
Third party commissions	9,415	9,270
Taxes, other than income	5,675	5,316
Insurance liabilities	3,377	3,954
Earn-outs related to acquisitions	1,056	295
Severance payments	702	970
Fair value of liability derivatives	512	4,716
Other	31,913	24,393
Accrued expenses and other liabilities	$ 165,127	$ 143,389
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued expenses and other liabilities	Accrued expenses and other liabilities
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued expenses and other liabilities