Financial Instruments (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Company owned life insurance policies	[1]	$ 29,908	$ 30,985
Deferred compensation plan, assets		29,908	30,985
Deferred compensation liabilities		23,275	22,559
Deferred compensation plan, liability		25,661	25,050
Interest Rate Swap No. 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of interest rate derivatives		$ 2,386	$ 2,123
Derivative, term of contract		10 years	10 years
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
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Company owned life insurance policies	[1]	$ 29,908	$ 30,985
Deferred compensation plan, assets		29,908	30,985
Deferred compensation liabilities		23,275	22,559
Deferred compensation plan, liability		25,661	25,050
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap No. 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of interest rate derivatives		$ 2,386	$ 2,123
Derivative, term of contract		10 years	10 years
Fair Value, Inputs, Level 2 [Member] | 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

[1] Company owned life insurance policies are intended to assist in the funding of the deferred compensation liabilities.