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Employee Benefit Plans, Financial Instruments Recorded At Fair Value On A Recurring Basis By The Plan (Details) - Pension Benefits [Member] - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | --- | ---
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | $ 122,995 | $ 109,746 | $ 124,226
Recurring Basis [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 122,995 | 109,746 |
Recurring Basis [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 74,268 | 67,080 |
Recurring Basis [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 48,727 | 42,666 |
Recurring Basis [Member] | Cash and Cash Equivalents [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 4,143 | 4,095 |
Recurring Basis [Member] | Cash and Cash Equivalents [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 4,143 | 4,095 |
Recurring Basis [Member] | Cash and Cash Equivalents [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Recurring Basis [Member] | Foreign Equity Mutual Funds [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 40,239 | 38,861 |
Recurring Basis [Member] | Foreign Equity Mutual Funds [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 40,239 | 38,861 |
Recurring Basis [Member] | Foreign Equity Mutual Funds [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Recurring Basis [Member] | Equity Mutual Funds [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 29,886 | 24,124 |
Recurring Basis [Member] | Equity Mutual Funds [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 29,886 | 24,124 |
Recurring Basis [Member] | Equity Mutual Funds [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Recurring Basis [Member] | US Government Bonds [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 58 | 76 |
Recurring Basis [Member] | US Government Bonds [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Recurring Basis [Member] | US Government Bonds [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 58 | 76 |
Recurring Basis [Member] | Corporate Bonds [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 48,669 | 42,590 |
Recurring Basis [Member] | Corporate Bonds [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | 0 | 0 |
Recurring Basis [Member] | Corporate Bonds [Member] | Level 2 [Member] |  |  |
Defined Benefit Plan, Information about Plan Assets [Abstract] |  |  |
Fair value of plan assets | $ 48,669 | $ 42,590 |

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- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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