Basis of Presentation - Immaterial Error Correction (Details) - Correction Of Net Loss (Income) Attributable To Noncontrolling Interest And Common Shareholders - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Increase in net loss attributable to noncontrolling interests	$ 0.7	$ 1.4
Decrease in earnings per share, basic and diluted (in dollars per share)	$ 0.01	$ 0.02