Pension Plan (Details) - Pension plan assets by level within the fair value hierarchy - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	$ 10,475,000	$ 10,148,000	$ 8,647,000
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	10,475,000	10,148,000
Fair Value, Inputs, Level 1 [Member] | Equity And Index Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	7,139,000	7,028,000
Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	3,336,000	3,120,000
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total