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Benefit Plans - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items] |  |  |
Minimum percentages of gain loss consider for amortization (in hundredths) | 10.00% |  |
Minimum value of outstanding noncallable bonds used in hypothetical cash flow bond matching exercise | $ 50.0 |  |
Future earnings period used in determining the expected average rate of earnings | 20 years |  |
Discretionary profit sharing contribution as a percentage of participant's eligible compensation (in hundredths) | 5.00% |  |
Matching contribution rate on employees' contributions (in hundredths) | 100.00% |  |
Employee contributions subject to employer match (in hundredths) | 4.00% |  |
Profit sharing and 401(k) savings plan expenses | $ 8.0 | $ 7.4 | $ 6.0
Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Lump sum pension plan benefit payments | $ 27.5 | $ 18.5 |
Pension Plan | Equity securities | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target asset allocations (in hundredths) | 40.00% |  |
Other Postretirement Benefit Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Minimum percentage return should exceed growth in consumer price index annually (in hundredths) | 5.75% |  |
Maximum investment in international mutual funds (in hundredths) | 30.00% |  |
Percent of international mutual funds equity allocation in emerging markets (in hundredths) | 3.00% |  |
Percent of international mutual funds equity allocation in companies primarily based in Europe and the Pacific Basin (in hundredths) | 20.00% |  |
Other Postretirement Benefit Plan | Equity securities | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Target asset allocations (in hundredths) | 100.00% |  |

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- Definition The amount of lump sum payments made from fund for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. This amount is included in total benefit payments from fund. + References No definition available. + Details
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- Definition The future earnings period, in years, used in determining the average rate of earnings expected on the classes of funds invested or to be invested to provide for the benefits of the plans. This was then used in selecting the expected long-term rate of return on assets included in the actuarial assumptions used in the valuation of projected benefit obligations, net periodic benefit costs and accumulated postretirement benefit obligation. + References No definition available. + Details
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- Definition The maximum investment in international mutual funds, as a percentage of the equity investments range, to total plan assets as of the measurement date of the latest statement of financial position. + References No definition available. + Details
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- Definition The minimum value of outstanding noncallable bonds used in a hypothetical cash flow bond matching exercise for purposes of selecting a discount rate related to actuarial assumptions used in the valuation of projected benefit obligations, net periodic benefit costs and accumulated postretirement benefit obligation. + References No definition available. + Details
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- Definition The company's discretionary profit sharing contribution as a percentage of each participant's eligible compensation. + References No definition available. + Details
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- Definition The minimum percentages that return should exceed growth in consumer price index annually. + References No definition available. + Details
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- Definition Represents minimum percentages of gain loss consider for amortization. + References No definition available. + Details
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- Definition The investment in international mutual funds primarily based in Europe and the Pacific Basin, as a percentage of the equity investments range. + References No definition available. + Details
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- Definition The investment in international mutual funds (emerging markets), as a percentage of the equity investments range. + References No definition available. + Details
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: 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 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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