Summary of Significant Accounting Policies Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2019	Mar. 31, 2018	Oct. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from contracts with customers	$ 428,997	$ 751,111
Scenario, Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase (decrease) in restricted cash			$ 1,474
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting for employee share-based payments				$ 3,926
Revenue from contracts with customers	$ 17,000	$ 32,000