Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Common shares	Additional paid-in surplus	Retained earnings	Accumulated other comprehensive (loss)	Non-controlling interests	Total
Cumulative effect of an accounting change			$ 1.6
Accumulated net foreign currency translation (losses)
Non-controlling interests						$ 0.2
Total equity			860.0
Total common shareholders' equity at Dec. 31, 2017	$ 1.2	$ 1,197.9	858.4	$ (140.5)
Capital contribution from former parent		1.4
Net income			141.5
Income attributable to non-controlling interests			(0.6)
Accrued dividends on Series A redeemable preference shares			(2.6)			(2.6)
Other, net			(0.1)
Balance at beginning of period at Dec. 31, 2017				(140.5)
Accumulated net foreign currency translation (losses)
Net change in foreign currency translation				(61.9)
Balance at the end of period at Jun. 30, 2018				(202.4)
Total common shareholders' equity at Jun. 30, 2018		1,199.3	998.2	(202.4)		1,996.3
Accumulated net foreign currency translation (losses)
Non-controlling interests						0.5
Total equity			900.4
Total common shareholders' equity at Mar. 31, 2018	1.2	1,197.9	900.4	(153.9)
Capital contribution from former parent		1.4
Net income			98.2
Income attributable to non-controlling interests			(0.4)
Balance at beginning of period at Mar. 31, 2018				(153.9)
Accumulated net foreign currency translation (losses)
Net change in foreign currency translation				(48.5)
Balance at the end of period at Jun. 30, 2018				(202.4)
Total common shareholders' equity at Jun. 30, 2018		1,199.3	998.2	(202.4)		1,996.3
Accumulated net foreign currency translation (losses)
Non-controlling interests					$ 1.0	1.0
Total equity						1,997.3
Non-controlling interests						1.7
Total equity			816.6
Total common shareholders' equity at Dec. 31, 2018	1.2	1,089.1	816.6	(202.4)		1,704.5
Share-based compensation		4.5
Other, net		(0.1)
Net income			112.3
Income attributable to non-controlling interests			(1.2)
Change in carrying value of Series B preference shares			(9.2)
Balance at beginning of period at Dec. 31, 2018				(202.4)
Accumulated net foreign currency translation (losses)
Net change in foreign currency translation				(26.7)
Balance at the end of period at Jun. 30, 2019				(229.1)
Total common shareholders' equity at Jun. 30, 2019		1,093.5	918.5	(229.1)		1,784.1
Accumulated net foreign currency translation (losses)
Non-controlling interests						2.2
Total equity			911.8
Total common shareholders' equity at Mar. 31, 2019	$ 1.2	1,090.2	911.8	(230.2)
Share-based compensation		3.3
Net income			8.2
Income attributable to non-controlling interests			(0.8)
Change in carrying value of Series B preference shares			(0.8)
Other, net			0.1
Balance at beginning of period at Mar. 31, 2019				(230.2)
Accumulated net foreign currency translation (losses)
Net change in foreign currency translation				1.1
Balance at the end of period at Jun. 30, 2019				(229.1)
Total common shareholders' equity at Jun. 30, 2019		$ 1,093.5	$ 918.5	$ (229.1)		1,784.1
Accumulated net foreign currency translation (losses)
Non-controlling interests					$ 3.0	3.0
Total equity						$ 1,787.1