CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Common Stock Including Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Non-controlling Interests	Total
Balance at Dec. 31, 2013	$ 818.3	$ 3,063.0	$ (6.7)	$ 9.8	$ 3,884.4
Balance (in shares) at Dec. 31, 2013	77,492,017
Increase (Decrease) in Stockholders' Equity
Net income		371.5		4.8	376.3
Other comprehensive loss			(42.2)		(42.2)
Consolidation of joint venture				22.6	22.6
Noncontrolling interest purchased				(4.2)	(4.2)
Payments to noncontrolling interest holders				(4.1)	(4.1)
Stock-based compensation	$ 22.3				22.3
Stock-based compensation (in shares)	11,830
Stock options exercised	$ 28.8				28.8
Stock options exercised (in shares)	593,204
Repurchase of common shares	$ (50.0)				$ (50.0)
Repurchase of common shares (in shares)	(759,800)				(759,800)
Stock-based compensation tax benefit (deficit)		2.7			$ 2.7
Cash dividends - $1.40 per share for the year ended on December 31, 2014		(108.7)			(108.7)
Balance at Dec. 31, 2014	$ 819.4	3,328.5	(48.9)	28.9	4,127.9
Balance (in shares) at Dec. 31, 2014	77,337,251
Increase (Decrease) in Stockholders' Equity
Net income		311.5		4.7	316.2
Other comprehensive loss			(50.8)		(50.8)
Noncontrolling interest purchased	$ (0.6)			(2.0)	(2.6)
Payments to noncontrolling interest holders				(3.0)	(3.0)
Stock-based compensation	$ 16.8				16.8
Stock-based compensation (in shares)	271,438
Stock options exercised	$ 15.1				15.1
Stock options exercised (in shares)	325,024
Repurchase of common shares	$ (355.5)				$ (355.5)
Repurchase of common shares (in shares)	(6,194,641)				(6,194,641)
Stock-based compensation tax benefit (deficit)		(1.3)			$ (1.3)
Delaware reincorporation	$ 38.6	(38.6)
Cash dividends and dividend equivalents - $1.65 and $1.60 per share for the year ended on December 31, 2016 and December 31, 2015, respectively		(120.1)			(120.1)
Balance at Dec. 31, 2015	$ 533.8	3,480.0	(99.7)	28.6	$ 3,942.7
Balance (in shares) at Dec. 31, 2015	71,739,072				71,739,072
Increase (Decrease) in Stockholders' Equity
Net income		304.3		4.8	$ 309.1
Other comprehensive loss			(5.0)		(5.0)
Payments to noncontrolling interest holders				(3.1)	(3.1)
Stock-based compensation	$ 18.0				18.0
Stock-based compensation (in shares)	188,576
Stock options exercised	$ 37.5				$ 37.5
Stock options exercised (in shares)	755,145
Repurchase of common shares (in shares)					0
Cumulative effect of change in accounting for stock-based compensation	$ 1.0	(0.6)			$ 0.4
Cash dividends and dividend equivalents - $1.65 and $1.60 per share for the year ended on December 31, 2016 and December 31, 2015, respectively		(120.5)			(120.5)
Balance at Dec. 31, 2016	$ 590.3	$ 3,663.2	$ (104.7)	$ 30.3	$ 4,179.1
Balance (in shares) at Dec. 31, 2016	72,682,793				72,682,793