Consolidated Statement of Equity - USD ($) $ in Millions	Total	Foreign Exchange Contract [Member]	Interest Rate Swap [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income Loss [Member]	Accumulated Other Comprehensive Income Loss [Member] Foreign Exchange Contract [Member]	Accumulated Other Comprehensive Income Loss [Member] Interest Rate Swap [Member]	Noncontrolling Interests [Member]
Beginning balance outstanding (in shares) at Dec. 31, 2017				151,561,284
Balance beginning of period at Dec. 31, 2017	$ 1,577.5			$ 0.0	$ 1,883.3	$ (90.6)	$ (427.1)			$ 211.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares forfeited (in shares)				(15,100)
Restricted stock grants (RSG) (in shares)				1,514,800
Shares retired due to RSG vesting (in shares)				(380,768)
Shares retired due to RSG vesting	(6.8)				(6.8)
Shares retired due to common stock repurchase program (in shares)				(8,488,141)
Shares retired due to common stock repurchase program	(153.3)			$ (153.2)	(151.3)	(2.0)
Stock based compensation	27.9				27.9
Other comprehensive income (loss):
Unrealized foreign currency translation loss, net of tax	(28.1)						(33.2)			5.1
Unrealized foreign currency derivative contract loss, net of tax		$ 17.0						$ 17.0
Unrealized loss on marketable securities, net of tax	(0.1)						(0.1)
Common stock dividends	(83.4)					(83.4)
Net income	179.2					119.3				59.9
Contributions from noncontrolling interests	16.8									16.8
Distributions to noncontrolling interests	(104.9)									(104.9)
Ending balance outstanding (in shares) at Sep. 30, 2018				144,192,075
Balance end of period at Sep. 30, 2018	1,441.8			$ 0.0	1,753.1	(56.7)	(443.4)			188.8
Beginning balance outstanding (in shares) at Jun. 30, 2018				144,405,875
Balance beginning of period at Jun. 30, 2018	1,449.7			$ 0.0	1,747.7	(40.7)	(436.7)			179.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares forfeited (in shares)				(12,500)
Shares retired due to common stock repurchase program (in shares)				(201,300)
Shares retired due to common stock repurchase program	(4.6)				(3.8)	(0.8)
Stock based compensation	9.2				9.2
Other comprehensive income (loss):
Unrealized foreign currency translation loss, net of tax	(7.5)						(6.6)			(0.9)
Unrealized foreign currency derivative contract loss, net of tax		(0.1)						(0.1)
Common stock dividends	(27.3)					(27.3)
Net income	12.9					12.1				0.8
Contributions from noncontrolling interests	10.5									10.5
Distributions to noncontrolling interests	(1.0)									(1.0)
Ending balance outstanding (in shares) at Sep. 30, 2018				144,192,075
Balance end of period at Sep. 30, 2018	1,441.8			$ 0.0	1,753.1	(56.7)	(443.4)			188.8
Beginning balance outstanding (in shares) at Dec. 31, 2018				143,205,394
Balance beginning of period at Dec. 31, 2018	1,431.2			$ 0.0	1,744.6	(56.4)	(441.5)			184.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock grants (RSG) (in shares)				54,875
Shares retired due to RSG vesting (in shares)				(658,885)
Shares retired due to RSG vesting	(14.0)				(14.0)
Shares retired due to common stock repurchase program (in shares)				(152,252)
Shares retired due to common stock repurchase program				$ (2.8)	(2.7)	(0.1)
Stock based compensation	23.9				23.9
Other comprehensive income (loss):
Unrealized foreign currency translation loss, net of tax	(17.3)						(26.3)			9.0
Unrealized currency derivative contracts gain (loss)		33.1	$ (1.9)					33.1	$ (1.9)
Common stock dividends	(89.8)					(89.8)
Net income	162.2					66.2				96.0
Contributions from noncontrolling interests	11.0									11.0
Distributions to noncontrolling interests	(259.9)									(259.9)
Ending balance outstanding (in shares) at Sep. 30, 2019				142,449,132
Balance end of period at Sep. 30, 2019	1,275.7			$ 0.0	1,751.8	(80.1)	(436.6)			40.6
Beginning balance outstanding (in shares) at Jun. 30, 2019				142,534,436
Balance beginning of period at Jun. 30, 2019	1,290.3			$ 0.0	1,747.3	(71.8)	(429.3)			44.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares retired due to RSG vesting (in shares)				(85,304)
Shares retired due to RSG vesting	(1.8)				(1.8)
Stock based compensation	6.3				6.3
Other comprehensive income (loss):
Unrealized foreign currency translation loss, net of tax	(31.7)						(30.7)			(1.0)
Unrealized currency derivative contracts gain (loss)		$ 24.9	$ (1.5)					$ 24.9	$ (1.5)
Common stock dividends	(29.0)					(29.0)
Net income	19.4					20.7				(1.3)
Contributions from noncontrolling interests	0.5									0.5
Distributions to noncontrolling interests	(1.7)									(1.7)
Ending balance outstanding (in shares) at Sep. 30, 2019				142,449,132
Balance end of period at Sep. 30, 2019	$ 1,275.7			$ 0.0	$ 1,751.8	$ (80.1)	$ (436.6)			$ 40.6