Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2020	Oct. 01, 2019	Sep. 30, 2019
Accounting Policies [Abstract]
Cash and cash equivalents			$ 118,374		$ 220,370
Restricted cash and cash equivalents			$ 56,300		$ 33,300
Restricted cash and cash equivalents, balance sheet location			us-gaap:OtherAssets
Right-of-use asset, amount			$ 15,100	$ 15,700
Lease liability, amount			15,057	$ 15,500
Cumulative effect of adopting Accounting Standards Update	$ 88	$ 394	$ 88