Financial Instruments (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Company owned life insurance policies	[1]	$ 30,985	$ 47,009
Company owned life insurance policies, assets		30,985	47,009
Deferred compensation liabilities		22,559	34,081
Deferred compensation plan, liability		25,050	35,135
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Company owned life insurance policies	[1]	30,985	47,009
Company owned life insurance policies, assets		30,985	47,009
Deferred compensation liabilities		22,559	34,081
Deferred compensation plan, liability		25,050	$ 35,135
Interest Rate Swap No. 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of interest rate derivatives		$ 368
Derivative, term of contract		5 years	5 years
Interest Rate Swap No. 2 [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of interest rate derivatives		$ 368
Derivative, term of contract		5 years
Interest Rate Swap No. 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of interest rate derivatives		$ 2,123	$ 1,054
Derivative, term of contract		10 years	10 years
Interest Rate Swap No. 1 [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of interest rate derivatives		$ 2,123	$ 1,054
Derivative, term of contract		10 years	10 years

[1] (1) Deferred compensation assets consist of the cash surrender value of life insurance policies and are intended to assist        in the funding of the deferred compensation liabilities.