Stockholders' Deficit - Stock Repurchase Program (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2019	Apr. 17, 2019	Dec. 06, 2018	Apr. 18, 2018	Jun. 08, 2017	Apr. 26, 2016	Jan. 22, 2015
Class of Stock [Line Items]
Approved stock repurchase program, authorized amount (up to)						$ 200,000	$ 100,000	$ 200,000	$ 200,000	$ 400,000	$ 450,000
Repurchase of common stock, amount	$ (50,000)	$ (50,000)	$ (100,000)	$ (50,000)
Remaining capacity under the stock repurchase program	$ 246,300				$ 246,300
Open Market Transaction
Class of Stock [Line Items]
Repurchase of common stock (in shares)	418,019				800,298
Repurchase of common stock, amount	$ 50,000				$ 100,000