Multiemployer Plans, Certified Zone Status, Percent Funded Limit for Green Status

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Multiemployer Plans, Certified Zone Status, Percent Funded Limit for Red Status

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Multiemployer Plans, Certified Zone Status, Percent Funded Limit for Yellow Status

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Multiemployer Plans, Collective-Bargaining Arrangement, Maximum Hours of Work Per Week for Employer Contribution

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Multiemployer Plans, Collective-Bargaining Arrangement, Rate of Employer Contribution

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Multiemployer Plans, Maximum Percentage of Total Contribution

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Amount of contributions made to multiemployer plan by employer.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947

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Post Retirement Benefits - Multiemployer Plans (Details)	12 Months Ended
	Aug. 10, 2019 $ / h	Dec. 31, 2018 USD ($)	Aug. 05, 2018 $ / h	Dec. 31, 2017 USD ($)	Aug. 06, 2017 $ / h
Multiemployer plans:
Certified zone status, percent funded limit for red status		65.00%
Certified zone status, percent funded limit for yellow status		80.00%
Certified zone status, percent funded limit for green status		80.00%
Multi-employer plan contributions \| $		$ 760,000		$ 647,000
Multiemployer plan, postretirement benefit
Multiemployer plans:
Maximum percentage of total contribution		5.00%
Multiemployer plans, collective-bargaining arrangement, maximum hours of work per week for employer contribution		40 hours
Multiemployer plans, collective-bargaining arrangement, rate of employer contribution			1.50		1.45
Scenario, Forecast [Member] \| Multiemployer plan, postretirement benefit
Multiemployer plans:
Multiemployer plans, collective-bargaining arrangement, rate of employer contribution	1.55