Acquisitions - Summary of Preliminary Allocation of Purchase Price to Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions		2 Months Ended	3 Months Ended	9 Months Ended
	Aug. 01, 2019	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Total consideration transferred				$ (1.5)	$ 452.6
Assets:
Goodwill		$ 2,207.7		2,207.7		$ 2,216.9
Protective
Assets:
Goodwill		1,684.2		1,684.2		$ 1,689.0
Automated Packaging Systems
Assets:
Identifiable intangible assets, net	$ 80.5
Measurement Period
Property and equipment, net	2.4
Automated Packaging Systems | Protective
Business Acquisition [Line Items]
Total consideration transferred	445.7			441.4
Assets:
Cash and cash equivalents	16.0	15.8		15.8
Trade receivables, net	37.3	37.3		37.3
Other receivables	0.3	0.3		0.3
Inventories, net	40.7	40.0		40.0
Prepaid expenses and other current assets	2.3	2.3		2.3
Property and equipment, net	76.9	85.6		85.6
Identifiable intangible assets, net	81.1	80.5		80.5
Goodwill	261.3	246.7		246.7
Operating lease right-of-use-assets		4.3		4.3
Other non-current assets	24.7	25.8		25.8
Total assets	540.6	538.6		538.6
Liabilities:
Accounts payable	12.0	12.0		12.0
Current portion of long-term debt	2.6	2.1		2.1
Current portion of operating lease liabilities		1.5		1.5
Other current liabilities	56.2	52.9		52.9
Long-term debt, less current portion	4.3	4.0		4.0
Long-term operating lease liabilities, less current portion		2.8		2.8
Deferred taxes		0.5		0.5
Other noncurrent liabilities	19.8	21.4		21.4
Total liabilities	$ 94.9	97.2		$ 97.2
Measurement Period
Adjustment to consideration transferred			$ (4.3)
Cash and cash equivalents		(0.2)
Inventories, net		(0.7)
Property and equipment, net		8.7
Identifiable intangible assets, net		(0.6)
Goodwill		(14.6)
Operating lease right-of-use-assets		4.3
Other non-current assets		1.1
Total assets		(2.0)
Current portion of long-term debt		(0.5)
Current portion of operating lease liabilities		1.5
Other current liabilities		(3.3)
Long-term debt, less current portion		(0.3)
Long-term operating lease liabilities, less current portion		2.8
Deferred taxes		0.5
Other noncurrent liabilities		1.6
Total liabilities		$ 2.3