Pension Plans and Other Postretirement Benefit Plans - Deferred Compensation Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member]
Deferred Compensation Arrangement With Individual Excluding Share Based Payments And Postretirement Benefits [Line Items]
Deferred compensation assets and liabilities	$ 9,174	$ 8,948

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.

No definition available.

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