Debt (Details) $ in Thousands, shares in Millions	12 Months Ended
	Sep. 30, 2019 USD ($) shares	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	May 20, 2019 USD ($) shares
Debt Disclosure [Abstract]
Loans Payable to Bank, Noncurrent	$ 0	$ 30,247
Debt Issuance Costs, Noncurrent, Net	782	912
Other Long-term Debt, Noncurrent	299	229
Long-term debt	299	$ 29,564
Line of Credit Facility, Remaining Borrowing Capacity	93,532
Letters of Credit Outstanding, Amount	6,468
Line of Credit Facility, Interest Rate at Period End		4.25%
Interest Expense, Debt	1,857	$ 1,946	$ 1,702
Line of Credit Facility, Maximum Borrowing Capacity	100,000
Liquidity	$ 112,467
Stock Repurchase Program, Number of Shares Authorized to be Repurchased | shares	1.5			1.0
Stock Repurchase Program, Authorized Amount				$ 25,000
Fixed Charge Coverage Ratio	4.7