Quarterly Financial Data (Schedule of Quarterly Results) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Quarterly Financial Data [Abstract]
Revenue	$ 638.0	$ 550.2	$ 506.7	$ 504.9	$ 507.3	$ 478.0	$ 369.6	$ 366.8	$ 2,199.8	$ 1,721.7	$ 1,347.1
Operating costs and expenses
Operating costs (excluding depreciation and amortization and including stock-based compensation)	234.2	195.0	179.9	173.8	182.7	170.8	112.2	113.0	782.9	578.7	413.5
Selling, general and administrative expenses (including stock-based compensation)	117.1	108.8	104.7	105.6	104.3	112.5	85.0	84.6	436.2	386.4	358.4
Depreciation and amortization	181.3	155.7	131.4	138.5	148.3	137.2	113.7	117.1	606.9	516.3	406.2
Total operating costs and expenses	532.6	459.5	416.0	417.9	435.3	420.5	310.9	314.7	1,826.0	1,481.4	1,178.1
Operating income	105.4	90.7	90.7	87.0	72.0	57.5	58.7	52.1	373.8	240.3	169.0
Other expenses
Interest expense	(71.5)	(63.0)	(53.7)	(53.3)	(57.4)	(57.7)	(51.2)	(53.8)	(241.5)	(220.1)	(214.0)
Loss on extinguishment of debt	(13.7)	(4.5)			(33.8)				(18.2)	(33.8)	(94.3)
Foreign currency income/(loss) on intercompany loans	14.4	3.9	(17.4)	(11.2)	(24.9)	(11.1)	(7.1)	(10.7)	(10.3)	(53.8)	(24.4)
Other (expense)/income, net	(0.4)	0.5	0.4	(0.2)	0.1	(0.2)	(0.1)	(0.1)	0.3	(0.3)	(0.4)
Total other expenses, net	(71.2)	(63.1)	(70.7)	(64.7)	(116.0)	(69.0)	(58.4)	(64.6)	(269.7)	(308.0)	(333.1)
Income/(loss) from operations before income taxes	34.2	27.6	20.0	22.3	(44.0)	(11.5)	0.3	(12.5)	104.1	(67.7)	(164.1)
Provision/(benefit) for income taxes	11.0	0.6	0.2	6.6	(13.1)	7.8	11.1	2.7	18.4	8.5	(8.8)
Net Income Loss	$ 23.2	$ 27.0	$ 19.8	$ 15.7	$ (30.9)	$ (19.3)	$ (10.8)	$ (15.2)	85.7	(76.2)	(155.3)
Net income/(loss)									$ 85.7	$ (76.2)	$ (155.3)