CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Millions	Common Stock	Common Stock and Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Non-controlling Interests	Total
Balance at Dec. 31, 2018		$ 136.4	$ 4,637.9	$ (102.7)	$ 7.9	$ 4,679.5
Balance (in shares) at Dec. 31, 2018	66,882
Increase (Decrease) in Stockholders' Equity
Net income			190.1		1.5	191.6
Other comprehensive income (loss)				6.8		6.8
Stock-based compensation, net		(1.3)				(1.3)
Stock-based compensation, net (in shares)	333
Stock options exercised		0.8				$ 0.8
Stock options exercised (in shares)	20
Repurchase of common shares (in shares)						0
Cash dividends - $0.55 and $0.625 per share and dividend equivalents for the quarter ended March 31, 2019 and March 31, 2020, respectively			(38.2)			$ (38.2)
Balance at Mar. 31, 2019		135.9	4,789.8	(95.9)	9.4	4,839.2
Balance (in shares) at Mar. 31, 2019	67,235
Balance at Dec. 31, 2019		122.2	5,189.5	(105.1)	7.5	$ 5,214.1
Balance (in shares) at Dec. 31, 2019	66,854					66,854
Increase (Decrease) in Stockholders' Equity
Net income			61.7		1.2	$ 62.9
Other comprehensive income (loss)				(31.4)		(31.4)
Noncontrolling interest purchased		(6.9)			(1.1)	(8.0)
Dividend to noncontrolling interest holder					(0.5)	(0.5)
Stock-based compensation, net		3.8				3.8
Stock-based compensation, net (in shares)	111
Stock options exercised		0.3				0.3
Stock options exercised (in shares)	6
Repurchase of common shares		(119.3)	(180.7)			$ (300.0)
Repurchase of common shares (in shares)	(3,330)					3,300
Cash dividends - $0.55 and $0.625 per share and dividend equivalents for the quarter ended March 31, 2019 and March 31, 2020, respectively			(41.9)			$ (41.9)
Balance at Mar. 31, 2020		$ 0.1	$ 5,028.6	$ (136.5)	$ 7.1	$ 4,899.3
Balance (in shares) at Mar. 31, 2020	63,641					63,641