v3.20.1

Employee Benefit Plans (Investment Strategies) (Details) | 12 Months Ended
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Dec. 31, 2019
Small-Cap Fund [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Small-cap fund
Fund's Investment Strategy | Seeks to track performance of the Center for Research in Security Prices (“CRSP”) US Small Cap Index
Mid-Cap Fund [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Mid-cap fund
Fund's Investment Strategy | Seeks to track performance of the CRSP US Mid Cap Index
Large-Cap Fund [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Large-cap fund
Fund's Investment Strategy | Seeks to track performance of the Standard & Poor’s 500 Index
International Equity Fund [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | International equity fund
Fund's Investment Strategy | Seeks long-term growth of capital by investing 65% or more of assets in international equities
Short-Term Bond Fund [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Short-term bond fund
Fund's Investment Strategy | Seeks current income with limited price volatility through investment in primarily high quality bonds
Intermediate-Term Bond Funds [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Intermediate-term bond fund
Fund's Investment Strategy | Seeks moderate and sustainable level of current income by investing primarily in high quality fixed income securities with maturities from five to ten years
Long-Term Investment Grade Bond Fund [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Long-term investment grade bond funds
Fund's Investment Strategy | Seek high and sustainable current income through investment primarily in long-term high grade bonds
Short-Term Investment Fund [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Short-term investment fund
Fund's Investment Strategy | Invests in high quality short-term money market instruments issued by the U.S. Treasury
Group Annuity Contract [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Defined Benefit Plan, Description | Group annuity contract
Fund's Investment Strategy | Earns interest quarterly equal to the effective yield of the 91-day U.S. Treasury bill

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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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- Definition Description of investment policy and strategy for defined benefit plan asset. Includes, but is not limited to, investment allocation decision and factor pertinent to understanding investment policy and strategy for plan asset. Factor includes, but is not limited to, investment goal, risk management practice, permitted and prohibited investment including use of derivative, diversification, and relationship between plan asset and obligation. + 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 Description of defined benefit pension and other postretirement plans. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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 + Details
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