Stockholders' Deficit - Stock Repurchase Program (Details) - USD ($)	3 Months Ended			9 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 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)					$ 100,000,000	$ 200,000,000	$ 200,000,000.0	$ 400,000,000.0	$ 450,000,000.0
Repurchase of common stock, amount	$ 75,000,000	$ 100,000,000	$ 50,000,000
Remaining capacity under the stock repurchase program	$ 221,300,000			$ 221,300,000
Open Market Transaction
Class of Stock [Line Items]
Repurchase of common stock (in shares)	777,569			2,426,476
Repurchase of common stock, amount	$ 75,000,000			$ 225,000,000