Unaudited Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Parent [Member]	Common Stock [Member] Common Class A [Member]	Common Stock [Member] Common Class B [Member]	Treasury Stock [Member]	Capital in Excess of Par Value [Member]	Retained Earnings [Member]	Foreign Currency Translation Adjustment [Member]	Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]	Deferred Gain (Loss) on Cash Flow Hedging [Member]	Pension Adjustment [Member]	Noncontrolling Interest [Member]
Stockholders' Equity:
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 1.1	$ 1.1					$ 3.9		$ (2.8)
Balance at Dec. 31, 2017	572.4	565.5	$ 0.1	$ 0.1	$ (31.5)	$ 323.8	389.1	$ (58.5)	2.8	$ (1.5)	$ (58.9)	$ 6.9
Capital in Excess of Par Value
Stock-based compensation	1.9	1.9				1.9
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0.0	0.0			7.3	(7.3)
Treasury Stock, Value, Acquired, Cost Method	(0.6)	(0.6)			(0.6)
Retained Earnings
Net Income Attributable to Stockholders	20.5	20.5					20.5
Cash dividends	(10.4)	(10.1)					(10.1)
Accumulated Other Comprehensive Income (Loss)
Foreign currency translation adjustment	(18.4)							(18.4)
Deferred gain (loss) on cash flow hedging	(3.5)									(3.5)
Current period pension adjustment	0.7										0.7
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(21.2)	(21.2)
Reclassification of hedging activities into earnings	(1.2)									(1.2)
Reclassification of pension into earnings	1.4										1.4
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.2	0.2
Net Income	20.6
Noncontrolling Interest Items [Abstract]
Net (income) loss attributable to noncontrolling interest	0.1											0.1
Noncontrolling Interest, Increase from Business Combination	27.0											27.0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders												(0.3)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest	(1.1)											(1.1)
Balance at Jun. 30, 2018	589.9	557.3	0.1	0.1	(24.8)	318.4	403.4	(76.9)	0.0	(6.2)	(56.8)	32.6
Balance at Mar. 31, 2018	608.0	600.9	0.1	0.1	(25.1)	317.5	402.9	(48.7)	0.0	12.3	(58.2)	7.1
Capital in Excess of Par Value
Stock-based compensation	1.2	1.2				1.2
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0.0	0.0			0.3	(0.3)
Retained Earnings
Net Income Attributable to Stockholders	5.6	5.6					5.6
Cash dividends	(5.4)	(5.1)					(5.1)
Accumulated Other Comprehensive Income (Loss)
Foreign currency translation adjustment	(28.2)							(28.2)
Unrealized gain on available for sale securities									0.0
Deferred gain (loss) on cash flow hedging	(16.5)									(16.5)
Current period pension adjustment	0.7										0.7
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(44.0)	(44.0)
Reclassification of hedging activities into earnings	(2.0)									(2.0)
Reclassification of pension into earnings	0.7										0.7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(1.3)	(1.3)
Net Income	5.7
Noncontrolling Interest Items [Abstract]
Net (income) loss attributable to noncontrolling interest	0.1											0.1
Noncontrolling Interest, Increase from Business Combination	27.0											27.0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders												(0.3)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest	(1.3)											(1.3)
Balance at Jun. 30, 2018	589.9	557.3	0.1	0.1	(24.8)	318.4	403.4	(76.9)	0.0	(6.2)	(56.8)	32.6
Stockholders' Equity:
Cumulative Effect of New Accounting Principle in Period of Adoption	1.4	1.4					5.3			0.9	(4.8)
Balance at Dec. 31, 2018	559.5	527.4	0.1	0.1	(24.1)	321.5	407.3	(85.9)	0.0	(15.5)	(76.1)	32.1
Capital in Excess of Par Value
Stock-based compensation	4.8	4.8				4.8
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0.0	0.0			7.6	(7.6)
Treasury Stock, Value, Acquired, Cost Method	(0.2)	(0.2)			(0.2)
Retained Earnings
Net Income Attributable to Stockholders	19.6	19.6					19.6
Cash dividends	(10.5)	(10.4)					(10.4)
Accumulated Other Comprehensive Income (Loss)
Foreign currency translation adjustment	0.2							0.2
Deferred gain (loss) on cash flow hedging	(10.1)									(10.1)
Current period pension adjustment	0.0										0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(9.9)	(9.9)
Reclassification of hedging activities into earnings	3.3									3.3
Reclassification of pension into earnings	1.6										1.6
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	4.9	4.9
Net Income	20.1
Noncontrolling Interest Items [Abstract]
Net (income) loss attributable to noncontrolling interest	0.5											0.5
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders												(0.1)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest	0.0
Balance at Jun. 30, 2019	570.1	537.6	0.1	0.1	(16.7)	318.7	421.8	(85.7)	0.0	(21.4)	(79.3)	32.5
Balance at Mar. 31, 2019	551.4	519.5	0.1	0.1	(17.1)	317.4	410.8	(88.2)	0.0	(23.6)	(80.0)	31.9
Capital in Excess of Par Value
Stock-based compensation	1.7	1.7				1.7
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0.0	0.0			0.4	(0.4)
Retained Earnings
Net Income Attributable to Stockholders	16.2	16.2					16.2
Cash dividends	(5.3)	(5.2)					(5.2)
Accumulated Other Comprehensive Income (Loss)
Foreign currency translation adjustment	2.5							2.5
Unrealized gain on available for sale securities									0.0
Deferred gain (loss) on cash flow hedging	(0.3)									(0.3)
Current period pension adjustment	0.0										0.0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	2.2	2.2
Reclassification of hedging activities into earnings	2.5									2.5
Reclassification of pension into earnings	0.7										0.7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	3.2	3.2
Net Income	16.9
Noncontrolling Interest Items [Abstract]
Net (income) loss attributable to noncontrolling interest	0.7											0.7
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders												(0.1)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest	0.0
Balance at Jun. 30, 2019	$ 570.1	$ 537.6	$ 0.1	$ 0.1	$ (16.7)	$ 318.7	$ 421.8	$ (85.7)	$ 0.0	$ (21.4)	$ (79.3)	$ 32.5