Debt (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Debt Disclosure [Abstract]
Revolving loan	$ 12	$ 0
Other long-term debt	205	299
Long-term debt	217	299
Debt Issuance Costs, Noncurrent, Net	736	$ 782
Letters of Credit Outstanding, Amount	5,664
Line of Credit Facility, Remaining Borrowing Capacity	94,324
Line of Credit Facility, Interest Rate at Period End		1.48%
Interest expense	777	$ 1,857	$ 1,946
Line of Credit Facility, Maximum Borrowing Capacity	100,000
Liquidity	$ 147,902
Fixed Charge Coverage Ratio	8.3