4. Intangible Assets, Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Oct. 01, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period	$ 0.0
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	519.8		$ 525.6
Accumulated Amortization	(381.7)		(380.3)
Net Carrying Amount	138.1		145.3
Amortization [Abstract]
Amortization expense	5.9	$ 5.5
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles				$ 3.4
Intangible Assets, Gross (Excluding Goodwill)	$ 520.0		$ 525.8
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	6 years		6 years
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	$ 105.1		$ 107.2
Accumulated Amortization	(74.5)		(74.3)
Net Carrying Amount	$ 30.6		$ 32.9
Know How [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	5 years		5 years
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	$ 187.0		$ 188.5
Accumulated Amortization	(162.4)		(162.6)
Net Carrying Amount	$ 24.6		$ 25.9
Developed Technology Rights [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	8 years		8 years
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	$ 142.1		$ 144.2
Accumulated Amortization	(94.4)		(93.9)
Net Carrying Amount	$ 47.7		$ 50.3
Licensing Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	8 years		8 years
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	$ 76.0		$ 76.0
Accumulated Amortization	(45.2)		(44.4)
Net Carrying Amount	$ 30.8		$ 31.6
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	8 years		8 years
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	$ 6.4		$ 6.4
Accumulated Amortization	(3.7)		(3.6)
Net Carrying Amount	$ 2.7		$ 2.8
Noncompete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	5 years		6 years
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	$ 3.1		$ 3.2
Accumulated Amortization	(1.4)		(1.4)
Net Carrying Amount	$ 1.7		$ 1.8
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	0 years		0 years
Finite-Lived Intangible Assets, Net [Abstract]
Purchase Price	$ 0.1		$ 0.1
Accumulated Amortization	(0.1)		(0.1)
Net Carrying Amount	0.0		0.0
In Process Research and Development [Member]
Amortization [Abstract]
Indefinite-lived Intangible Assets (Excluding Goodwill)	$ 0.2		$ 0.2