Debt and Credit Facilities Credit Facility (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018	Apr. 15, 2016
Line of Credit Facility [Line Items]
Debt Issuance Costs, Noncurrent, Net	$ 594	$ 594		$ 843
Loss on extinguishment of debt	(900)	(910)	$ 0
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	236,700	236,700			$ 242,500
Letters of Credit Outstanding, Amount	$ 5,800	$ 5,800
Minimum | London Interbank Offered Rate [Member] | Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%
Minimum | Base Rate [Member] | Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.50%
Maximum | London Interbank Offered Rate [Member] | Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.75%
Maximum | Base Rate [Member] | Revolving Credit Facility Due April Fifteenth Twenty Twenty One [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.75%