Income Taxes (Summary of (Benefit)/Provision for Income Taxes from Continuing Operations) (Detail) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Jun. 30, 2015	[1]	Mar. 31, 2015	[1],[2],[3]	Dec. 31, 2014	[1]	Sep. 30, 2014	[1]	Jun. 30, 2014	[4],[5]	Mar. 31, 2014	[4],[6]	Dec. 31, 2013	[4],[7],[8]	Sep. 30, 2013	[4]	Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2013
Current Income Taxes
Federal																	$ 1.7		$ 6.2
State																	4.4		3.6		$ 1.7
Foreign																	(1.6)		3.3
Total																	4.5		13.1		1.7
Deferred Income Taxes
Federal																	(8.7)		23.8		(25.7)
State																	(6.9)		1.0		(3.7)
Foreign																	2.3		(0.6)		3.5
Total																	(13.3)		24.2		(25.9)
Total (benefit)/provision for income taxes	$ 4.6		$ (18.4)		$ (4.4)		$ 9.4		$ 10.1		$ 9.5		$ 8.4		$ 9.3		$ (8.8)	[1]	$ 37.3	[4]	$ (24.2)

[1] The Company realized an increase in revenue and operating expenses beginning July 1, 2014 as a result of the acquisition of AtlantaNap and Neo.

[2] The Company realized an increase in revenue and operating expenses beginning February 23, 2015 as a result of the acquisition of Latisys.

[3] The Company realized an increase in revenue and operating expenses beginning January 1, 2015 as a result of the acquisition of IdeaTek.

[4] The Company realized an increase in revenue and operating expenses beginning August 1, 2013 as a result of the acquisition of Corelink.

[5] The Company realized an increase in revenue and operating expenses beginning May 16, 2014 as a result of the acquisition of Geo.

[6] The Company realized an increase in revenue and operating expenses beginning March 4, 2014 as a result of the acquisition of CoreXchange.

[7] The Company realized an increase in revenue and operating expenses beginning October 1, 2013 as a result of the acquisition of Access.

[8] The Company realized an increase in revenue and operating expenses beginning October 2, 2013 as a result of the acquisition of Fiberlink.