Acquisitions (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Jun. 30, 2015	Feb. 23, 2015	Jun. 13, 2014	May 16, 2014
Deferred income tax assets:
Net operating loss carryforwards	$ 563.9	$ 448.7		$ 13.7
Deferred revenue	318.3	243.5
Allowance for doubtful accounts	14.8	10.2
Other	15.5	17.4
Total deferred income tax assets	995.4	770.8
Deferred income tax liabilities:
Property and equipment	(559.2)	(468.9)
Intangible assets	(321.5)	(327.2)
Total deferred income tax liabilities	(894.4)	(814.9)
Net deferred income tax liabilities	$ (34.3)	$ (45.2)
Latisys Holdings, LLC
Deferred income tax assets:
Net operating loss carryforwards			$ 53.4
Deferred revenue			1.3
Accrued expenses			0.2
Allowance for doubtful accounts			0.3
Other			1.2
Total deferred income tax assets			56.4
Deferred income tax liabilities:
Property and equipment			(42.0)
Intangible assets			(93.1)
Total deferred income tax liabilities			(135.1)
Net deferred income tax liabilities			$ (78.7)
Geo Networks Limited [Member]
Deferred income tax assets:
Net operating loss carryforwards					$ 2.5
Deferred revenue					4.4
Total deferred income tax assets					6.9
Deferred income tax liabilities:
Property and equipment					(32.9)
Intangible assets					(12.2)
Total deferred income tax liabilities					(45.1)
Net deferred income tax liabilities					$ (38.2)