Revenue from Contracts with Customers - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) segment	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Revenue recognition [Line Items]
Inventories, net	$ 1,059,000,000.0		$ 1,059,000,000.0		$ 997,100,000
Adjustment from current cost to LIFO cost basis	(29,900,000)		(29,900,000)		(44,100,000)
Sales	616,200,000	$ 770,300,000	1,308,700,000	$ 1,725,800,000
Cost of sales	573,500,000	695,600,000	1,180,200,000	1,516,300,000
Short-term contract assets	52,300,000	41,600,000	52,300,000	41,600,000	38,900,000	$ 38,500,000
Long-term contract assets	0	0	0	0	0	100,000
Other current liabilities	210,200,000		210,200,000		233,100,000
Other long-term liabilities	220,100,000		220,100,000		189,900,000
Short-term contract liabilities	103,800,000	109,800,000	103,800,000	109,800,000	111,800,000	78,700,000
Long-term contract liabilities	70,700,000	32,000,000.0	$ 70,700,000	32,000,000.0	32,000,000.0	$ 25,900,000
Number of business segments | segment			2
Revenue, Performance Obligation [Abstract]
Confirmed order backlog	1,600,000,000	1,500,000,000	$ 1,600,000,000	1,500,000,000
Confirmed orders with current performance obligations	0.75		0.75
Accounts receivable with customers	366,100,000		366,100,000		350,100,000
Contract costs for obtaining and fulfilling contracts	5,500,000		5,500,000		$ 5,400,000
Amortization of contract costs	$ 300,000	$ 400,000	$ 500,000	$ 700,000