Amount of cost for employer contribution to multiemployer pension plan determined to be individually insignificant.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

Name:	us-gaap_MultiemployerPlanPensionInsignificantEmployerContributionCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Employee Retirement Plans (Multiemployer Pension Plans) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($) plan	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Multiemployer Plans [Line Items]
Number of underfunded plans \| plan	2
Withdrawal obligation	$ 38.9
Payments to multiemployer pension plans	6.8	$ 5.2
Other Long-Term Liabilities
Multiemployer Plans [Line Items]
Withdrawal obligation	34.0		$ 35.7
Other Current Liabilities
Multiemployer Plans [Line Items]
Withdrawal obligation	$ 4.9		$ 8.4