Revenue from Contracts with Customers - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Revenue recognition [Line Items]
Inventories, net	$ 1,055,800,000		$ 1,055,800,000		$ 997,100,000
Adjustment from current cost to LIFO cost basis	(300,000)		(300,000)		(44,100,000)
Sales	725,700,000	$ 598,000,000.0	2,034,400,000	$ 2,323,800,000
Cost of sales	643,200,000	559,900,000	1,823,400,000	2,076,200,000
Short-term contract assets	55,700,000	41,700,000	55,700,000	41,700,000	38,900,000	$ 38,500,000
Long-term contract assets	0	0	0	0	0	100,000
Other current liabilities	223,000,000.0		223,000,000.0		233,100,000
Other long-term liabilities	220,100,000		220,100,000		189,900,000
Short-term contract liabilities	86,700,000	97,800,000	86,700,000	97,800,000	111,800,000	78,700,000
Long-term contract liabilities	74,000,000.0	31,900,000	$ 74,000,000.0	31,900,000	32,000,000.0	$ 25,900,000
Number of business segments | segment			2
Revenue, Performance Obligation [Abstract]
Confirmed order backlog	1,700,000,000	1,400,000,000	$ 1,700,000,000	1,400,000,000
Confirmed orders with current performance obligations	0.80		0.80
Accounts receivable with customers	506,100,000		506,100,000		350,100,000
Contract costs for obtaining and fulfilling contracts	5,300,000		5,300,000		$ 5,400,000
Amortization of contract costs	$ 200,000	$ 400,000	$ 700,000	$ 1,100,000