CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ 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, 2017		$ 594.6	$ 4,144.1	$ (71.6)	$ 32.8	$ 4,699.9
Balance (in shares) at Dec. 31, 2017	72,610,000
Increase (Decrease) in Stockholders' Equity
Net income			169.0		2.1	171.1
Other comprehensive income (loss)				(2.9)		(2.9)
Dividends to noncontrolling interest holders					(1.8)	(1.8)
Stock-based compensation, net		1.0				1.0
Stock-based compensation, net (in shares)	269,000
Stock options exercised		2.8				2.8
Stock options exercised (in shares)	48,000
Repurchase of common shares		(49.3)				(49.3)
Repurchase of common shares (in shares)	(584,000)
Cash dividends - $0.50 and $0.55 per share for the quarter ended on March 31, 2018 and March 31, 2019, respectively			(37.2)			(37.2)
Balance at Mar. 31, 2018		549.1	4,275.9	(74.5)	33.1	4,783.6
Balance (in shares) at Mar. 31, 2018	72,343,000
Balance at Dec. 31, 2018		136.4	4,637.9	(102.7)	7.9	$ 4,679.5
Balance (in shares) at Dec. 31, 2018	66,882,000					66,882,000
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)	333,000
Stock options exercised		0.8				$ 0.8
Stock options exercised (in shares)	20,000
Repurchase of common shares (in shares)						0
Cash dividends - $0.50 and $0.55 per share for the quarter ended on March 31, 2018 and March 31, 2019, 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	67,235,000					67,235,000