Segment Information - Segment Financial Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 670.7		$ 491.5
Operating profit	175.6		88.0
Stock-based compensation expense	5.9		5.4
Amortization of Acquisition-related Intangible Assets		$ 0.2
Cost investment impairment	2.2
Other expense, net	0.7		1.5
Income before income taxes	174.9		86.5
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit	199.0		106.0
Intersegment sales elimination
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	(0.1)		(0.1)
Corporate and Unallocated
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating profit	(23.4)		(18.0)
Stock-based compensation expense	(5.9)		(5.4)
Corporate general costs	(13.9)		(12.6)
Restructuring and related charges	(1.2)		0.0
Amortization of Acquisition-related Intangible Assets	(0.2)		0.0
Cost investment impairment	(2.2)		0.0
Proprietary Products | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	543.7		373.5
Operating profit	182.6		93.2
Contract-Manufactured Products | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	127.1		118.1
Operating profit	$ 16.4		$ 12.8