Significant Accounting Policies - Revenue Recognition (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in Accounting Estimate [Line Items]
Net sales	$ 891,700,000	$ 894,600,000	$ 803,500,000	$ 923,400,000	$ 896,200,000	$ 914,000,000.0	$ 1,000,000,000.0	$ 979,700,000	$ 3,513,200,000	$ 3,789,900,000	$ 3,580,800,000
Contracts Accounted for under Percentage of Completion
Change in Accounting Estimate [Line Items]
Net sales									0.90
Minimum | Transferred at Point in Time
Change in Accounting Estimate [Line Items]
Net sales									85
Minimum | Transferred over Time
Change in Accounting Estimate [Line Items]
Net sales									10
Maximum | Transferred at Point in Time
Change in Accounting Estimate [Line Items]
Net sales									90
Maximum | Transferred over Time
Change in Accounting Estimate [Line Items]
Net sales									$ 15