Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Jun. 30, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying value of the notes	$ 4,057.3		$ 4,057.3		$ 3,668.7
Hypothetical annual interest expense			20.3
Outstanding letters of credit	7.9		7.9
Hypothetical increase to interest rate swap fair value	6.1		$ 6.1
Interest Rate Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Hypothetical interest rate increase			100.00%
Change in fair value of interest rate swap	(0.3)	$ 2.3	$ 0.3	$ 1.8
Term Loan Facility due 2021 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying value of the notes	2,011.4		$ 2,011.4		1,627.0
Hypothetical interest rate increase			1.00%
Term Loan Facility due 2021 [Member] | LIBOR [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Floor rate			1.00%
Revolver interest rate			2.75%
Alternative Revolver interest rate			3.50
Notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying value of the notes	2,112.1		$ 2,112.1		2,112.7
Fair value of the notes	2,107.9		2,107.9		2,109.3
Revolver [Member] | Secured Debt [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Outstanding letters of credit	$ 0.0		$ 0.0		$ 0.0