Other Long-Term Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
Other long-term assets [Abstract]
Right of use asset	$ 30,260	$ 30,999
Vendor contract assets	2,481	2,889
SERP investment	1,282	1,214
Prepaid unamortized debt issuance cost - revolver	494	537
Other long-term assets	4,440	4,368
Total	$ 38,957	$ 40,007