Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Cumulative goodwill impairment charges		$ 434,600,000	$ 434,600,000
Amortization of intangible assets		34,000,000	$ 32,200,000	$ 41,000,000
Future amortization expense
Expected amortization expense, 2020		34,600,000
Expected amortization expense, 2021		33,500,000
Expected amortization expense, 2022		29,200,000
Expected amortization expense, 2023		14,900,000
Expected amortization expense, 2024		$ 14,100,000
Goodwill and intangible asset impairment	$ 0
Patents
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life of intangible assets acquired			14 years
Tradenames
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life of intangible assets acquired		15 years	14 years
Customer relationships (including distribution network)
Finite-Lived Intangible Assets [Line Items]
Weighted-average useful life of intangible assets acquired		18 years	15 years