Net Periodic Benefit Cost-Defined Benefit Plans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Net periodic benefit cost of the domestic non-contributory defined benefit plan
Interest cost	$ 160,000	$ 191,000	$ 320,000	$ 382,000
Expected return on plan assets	(318,000)	(249,000)	(636,000)	(498,000)
Amortization of net loss	51,000	47,000	92,000	94,000
Net periodic benefit	(107,000)	$ (11,000)	(224,000)	$ (22,000)
Expected contribution to Pension Plan (minimum)					$ 500,000
Employer contributions made to the defined benefit plan			1,250,000
Anticipated additional contributions anticipated during the remainder of the year (at least)	$ 250,000		$ 250,000