Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income attributable to controlling interests	$ 75.4	$ 54.0	$ 156.1	$ 113.4
Less: Total income available to participating unvested securities	0.0	(0.2)	(0.1)	(0.4)
Total net income attributable to ordinary shares	$ 75.4	$ 53.8	$ 156.0	$ 113.0
Denominator:
Weighted average ordinary shares outstanding (in shares)	89,970,871	106,363,714	92,996,289	108,057,432
Potential shares of common stock:
Restricted stock units (in shares)	1,429	150,995	79,775	174,278
Weighted-average diluted ordinary shares outstanding - diluted (in shares)	89,972,300	106,514,709	93,076,064	108,231,710
Earnings per share of common stock attributable to controlling interests:
Basic (in dollars per share)	$ 0.84	$ 0.51	$ 1.68	$ 1.05
Diluted (in dollars per share)	$ 0.84	$ 0.51	$ 1.68	$ 1.04
Employee options not included in computation of diluted EPS (in shares)	8,970,000		8,970,000