Noncontrolling Interest - Operating Partnership - Narrative (Details)	Jan. 24, 2013 shares	Jan. 23, 2013 shares	Sep. 30, 2016	Dec. 31, 2015 shares	Sep. 30, 2015
Noncontrolling Interest [Line Items]
Partners' capital units converted (in shares)	1,500,000
CyrusOne L.P.
Noncontrolling Interest [Line Items]
Issuance of partnership units (in shares)		123,700,000
Partnership reverse unit split, conversion ratio	2.8
Operating partnership units owned (in shares)	44,100,000
Cincinnati Bell Inc.
Noncontrolling Interest [Line Items]
Operating partnership units owned (in shares)				0
Remaining combined interest held	66.10%
Ownership %			5.00%	9.50%
Non- controlling Interest
Noncontrolling Interest [Line Items]
Ownership %			0.00%		8.70%