Description of Business and Accounting Policies (Details) $ / shares in Units, shares in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) shares	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Jul. 01, 2015 shares
Number of Operating Segments							3
Proceeds from Sale of Intangible Assets			$ 194,400,000
Equity Method Investment Sold, Partnership Units | shares	6.0	14.3		16.0
Sale of Partnership Units, Price Per Unit | $ / shares	$ 28.41	$ 29.88		$ 22.26
Proceeds from Sale of Equity Method Investments	$ 170,300,000	$ 426,000,000		$ 355,900,000	$ 426,000,000	$ 355,900,000
Total ownership interests in Equity Method Investee, Percentage		18.00%			18.00%			11.00%
Investment owned in CyrusOne Inc., Balance, Shares | shares		1.9			1.9			1.9
Investment owned in CyrusOne LP, Balance, Partnership Units | shares		12.3			12.3			6.3
Number of customers, exceeds 10% of total accounts receivable		1			1
Accounts Receivable from customers greater than 10%, percentage		$ 0.23			$ 0.23		$ 0.26
Revenue from customers greater than 10%, percentage		0.11		0.19	0.12	0.15
Dividends received from CyrusOne		$ 9,000,000		9,300,000	$ 15,000,000	$ 16,400,000
Payments to Acquire Equity Method Investments				$ 5,500,000