Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net income attributable to controlling interests	$ 18.9	$ 28.0	$ 51.5	$ 80.7
Less: Total income available to participating unvested securities	0.0	0.0	0.0	(0.1)
Total net income attributable to ordinary shares	$ 18.9	$ 28.0	$ 51.5	$ 80.6
Denominator:
Weighted average ordinary shares outstanding (in shares)	80,435,389	91,457,301	82,758,277	94,550,527
Potential shares of common stock:
Restricted stock units (in shares)	13,735	38,332	15,814	118,948
Weighted-average diluted ordinary shares outstanding - diluted (in shares)	80,449,124	91,495,633	82,774,091	94,669,475
Earnings per share of common stock attributable to controlling interests:
Basic (in dollars per share)	$ 0.23	$ 0.31	$ 0.62	$ 0.85
Diluted (in dollars per share)	$ 0.23	$ 0.31	$ 0.62	$ 0.85
Employee options not included in computation of diluted EPS (in shares)	7,474,000		7,474,000