Pension Plan (Details) - Components of net periodic pension cost - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Pension Plan (Details) - Components of net periodic pension cost [Line Items]
Interest cost	$ 63,000	$ 97,000
Expected return on plan assets	(210,000)	(203,000)
Amortization of net actuarial loss	80,000	70,000
Net periodic pension benefit	$ (67,000)	$ (36,000)