Restructuring Costs - Rollforward of restructuring liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring liability
Accrued costs	$ 8,505	$ 1,631	$ 12,254	$ 3,382
Employee Separation and other
Restructuring liability
Balance as of the beginning of the period			700
Accrued costs			(5,900)
Cash payments			(2,800)
Balance as of the end of the period	3,800		3,800
Consulting Costs
Restructuring liability
Balance as of the beginning of the period			200
Accrued costs			(6,400)
Cash payments			(6,100)
Balance as of the end of the period	$ 500		$ 500