CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred stock	Preferred stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common stock	Common stock Cumulative Effect, Period of Adoption, Adjusted Balance	Additional paid-in capital	Additional paid-in capital Cumulative Effect, Period of Adoption, Adjusted Balance	Retained earnings (deficit)	Retained earnings (deficit) Cumulative Effect, Period of Adoption, Adjustment	Retained earnings (deficit) Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury stock	Treasury stock Cumulative Effect, Period of Adoption, Adjusted Balance	Non-controlling interest	Non-controlling interest Cumulative Effect, Period of Adoption, Adjustment	Non-controlling interest Cumulative Effect, Period of Adoption, Adjusted Balance
Balance at Dec. 31, 2017	$ 766.7	$ 5.0	$ 771.7	$ 667.3	$ 667.3	$ 0.3	$ 0.3	$ 3.3	$ 3.3	$ (17.9)	$ 2.7	$ (15.2)	$ (179.0)	$ (179.0)	$ (49.6)	$ (49.6)	$ 342.3	$ 2.3	$ 344.6
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201409Member
Net income	$ 301.0									262.2							38.8
Cash dividends	(27.1)							(0.4)		(26.7)
Dividends paid to noncontrolling interest	(20.1)																(20.1)
Other comprehensive income (loss), net	(37.1)												(27.3)				(9.8)
Equity transactions with noncontrolling interest, net	0.6							0.4					0.1				0.1
Balance at Dec. 31, 2018	989.0			667.3		0.3		3.3		220.3			(206.2)		(49.6)		353.6
Net income	78.2									49.2							29.0
Cash dividends	(27.2)							(0.3)		(26.9)
Dividends paid to noncontrolling interest	(37.7)																(37.7)
Other comprehensive income (loss), net	(19.9)												(14.5)				(5.4)
Equity transactions with noncontrolling interest, net	(2.3)							0.3		(3.2)							0.6
Balance at Dec. 31, 2019	980.1			667.3		0.3		3.3		239.4			(220.7)		(49.6)		340.1
Net income	89.0									55.2							33.8
Cash dividends	(13.6)							(2.2)		(11.4)
Dividends paid to noncontrolling interest	(49.4)																(49.4)
Other comprehensive income (loss), net	1.4												1.3				0.1
Contribution of preferred stock				$ (667.3)				667.3
Equity transactions with noncontrolling interest, net	(0.6)							(0.1)		(0.3)							(0.2)
Balance at Dec. 31, 2020	$ 1,006.9					$ 0.3		$ 668.3		$ 282.9			$ (219.4)		$ (49.6)		$ 324.4