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Pension Plan Contributions (Details) - Pension Plan [Member] - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Multiemployer Plans [Line Items] |  |  |
Cash payment | $ 2,642 | $ 6,432 | $ 6,245
Multiemployer Plan Year Allocation Four [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Cash payment | 2,000 | 5,000 | 4,000
Multiemployer Plan Year Allocation One [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Cash payment | $ 642 |  |
Multiemployer Plan Year Allocation Two [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Cash payment |  | $ 1,432 |
Multiemployer Plan Year Allocation Three [Member] |  |  |
Multiemployer Plans [Line Items] |  |  |
Cash payment |  |  | $ 2,245

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- Definition Amount of contributions made to multiemployer plan by employer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -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 3: http://fasb.org/us-gaap/role/ref/legacyRef -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 + Details
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Balance Type: | credit
Period Type: | duration

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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- Details
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