Consolidated Statement of Equity - USD ($) $ in Millions	Total	Foreign Exchange Contract [Member]	Interest Rate Swap [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (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, 2018				0	143,205,394
Balance beginning of period at Dec. 31, 2018	$ 1,431.2			$ 0.0	$ 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)				$ (2.8)	(2.7)	(0.1)
Stock based compensation	23.9					23.9
Other comprehensive income (loss):
Unrealized foreign currency translation gain (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)
Preferred stock dividends	0.0
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				0	142,449,132
Balance end of period at Sep. 30, 2019	1,275.7			$ 0.0	$ 0.0	1,751.8	(80.1)	(436.6)			40.6
Beginning balance outstanding (in shares) at Jun. 30, 2019				0	142,534,436
Balance beginning of period at Jun. 30, 2019	1,290.3			$ 0.0	$ 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)
Shares retired due to common stock repurchase program	6.3					6.3
Other comprehensive income (loss):
Unrealized foreign currency translation gain (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				0	142,449,132
Balance end of period at Sep. 30, 2019	1,275.7			$ 0.0	$ 0.0	1,751.8	(80.1)	(436.6)			40.6
Beginning balance outstanding (in shares) at Dec. 31, 2019				300,000	142,283,109
Balance beginning of period at Dec. 31, 2019	1,719.2			$ 295.2	$ 0.0	1,754.5	46.2	(417.2)			40.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares forfeited (in shares)					(56,876)
Restricted stock grants (RSG) (in shares)					2,533,967
Shares retired due to RSG vesting (in shares)					(469,680)
Shares retired due to RSG vesting	(9.8)					(9.8)
Shares retired due to common stock repurchase program (in shares)					(2,216,388)
Shares retired due to common stock repurchase program					$ 36.5	(39.3)	2.8
Stock based compensation	24.5					24.5
Other comprehensive income (loss):
Unrealized foreign currency translation gain (loss), net of tax	33.7							34.3			(0.6)
Unrealized currency derivative contracts gain (loss)		(24.9)	(5.9)						(24.9)	(5.9)
Common stock dividends	(94.4)						(94.4)
Preferred stock dividends	(12.9)						(12.9)
Net income	(64.7)						(64.2)				(0.5)
Contributions from noncontrolling interests	2.8										2.8
Distributions to noncontrolling interests	(18.2)										(18.2)
KW Europe II deconsolidation	3.7										3.7
Ending balance outstanding (in shares) at Sep. 30, 2020				300,000	142,074,132
Balance end of period at Sep. 30, 2020	1,516.6			$ 295.2	$ 0.0	1,729.9	(122.5)	(413.7)			27.7
Beginning balance outstanding (in shares) at Jun. 30, 2020				300,000	143,488,900
Balance beginning of period at Jun. 30, 2020	1,589.1			$ 295.2	$ 0.0	1,746.3	(70.2)	(423.5)			41.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares forfeited (in shares)					(56,876)
Shares retired due to RSG vesting (in shares)					(1,357,892)
Shares retired due to RSG vesting	(19.9)					(24.0)		4.1
Stock based compensation	7.6					7.6
Other comprehensive income (loss):
Unrealized foreign currency translation gain (loss), net of tax	28.8							28.0			0.8
Unrealized currency derivative contracts gain (loss)		$ (18.6)	$ 0.4						$ (18.6)	$ 0.4
Common stock dividends	(31.3)						(31.3)
Preferred stock dividends	(4.3)						(4.3)
Net income	(19.7)						(20.8)				1.1
Contributions from noncontrolling interests	0.9										0.9
Distributions to noncontrolling interests	(16.4)						0.0				(16.4)
Ending balance outstanding (in shares) at Sep. 30, 2020				300,000	142,074,132
Balance end of period at Sep. 30, 2020	$ 1,516.6			$ 295.2	$ 0.0	$ 1,729.9	$ (122.5)	$ (413.7)			$ 27.7