4. Intangible Assets, Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Aug. 02, 2019	Mar. 04, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period	$ 28.7	$ 15.6		$ 44.3
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	514.3			514.3		$ 493.1
Accumulated Amortization	(367.5)			(367.5)		(360.0)
Net Carrying Amount	146.8			146.8		133.1
Amortization [Abstract]
Amortization expense	6.0		$ 7.0	17.1	$ 21.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							$ 26.8	$ 5.5
Intangible Assets, Gross (Excluding Goodwill)	514.5			514.5
Customer Relationships [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	101.4			101.4		88.7
Accumulated Amortization	(70.4)			(70.4)		(68.3)
Net Carrying Amount	31.0			31.0		20.4
Amortization [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							16.1
Know How [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	186.0			186.0		190.6
Accumulated Amortization	(158.9)			(158.9)		(159.8)
Net Carrying Amount	27.1			27.1		30.8
Developed Technology Rights [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	141.5			141.5		130.4
Accumulated Amortization	(90.1)			(90.1)		(86.6)
Net Carrying Amount	51.4			51.4		43.8
Amortization [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							8.1
Licensing Agreements [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	75.7			75.7		76.3
Accumulated Amortization	(43.3)			(43.3)		(40.9)
Net Carrying Amount	32.4			32.4		35.4
Trade Names [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	6.4			6.4		3.9
Accumulated Amortization	(3.5)			(3.5)		(3.3)
Net Carrying Amount	2.9			2.9		0.6
Amortization [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							2.5
Noncompete Agreements [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	3.2			3.2		3.2
Accumulated Amortization	(1.3)			(1.3)		(1.1)
Net Carrying Amount	1.9			1.9		$ 2.1
Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	0.1			0.1
Accumulated Amortization	0.0			0.0
Net Carrying Amount	0.1			$ 0.1
Amortization [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles							$ 0.1
Minimum [Member] | Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				1 year		1 year
Minimum [Member] | Know How [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				1 year		1 year
Minimum [Member] | Developed Technology Rights [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				1 year		1 year
Minimum [Member] | Licensing Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				6 years		7 years
Minimum [Member] | Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				2 years		2 years
Minimum [Member] | Noncompete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				6 years		7 years
Minimum [Member] | Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				1 year		0 years
Maximum [Member] | Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				10 years		6 years
Maximum [Member] | Know How [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				6 years		7 years
Maximum [Member] | Developed Technology Rights [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				13 years		10 years
Maximum [Member] | Licensing Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				10 years		11 years
Maximum [Member] | Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				10 years		6 years
Maximum [Member] | Noncompete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				6 years		7 years
Maximum [Member] | Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period				1 year		0 years
In Process Research and Development [Member]
Amortization [Abstract]
Indefinite-lived Intangible Assets (Excluding Goodwill)	$ 0.2			$ 0.2