Debt and Credit Facilities Credit Facility (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019	Apr. 15, 2016
Line of Credit Facility [Line Items]
Debt Issuance Costs, Noncurrent, Net	$ 229,655		$ 511
Loss on extinguishment of debt	(18,656)	$ (910)
Other Borrowings	230,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	9,700			$ 242,500
Letters of Credit Outstanding, Amount	2,800
Other Borrowings	$ 230,000
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%