Net Periodic Benefit Cost-Defined Benefit Plans (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Net periodic benefit cost of the domestic non-contributory defined benefit plan
Service cost	$ 0	$ 0
Interest cost	191,000	176,000
Expected return on plan assets	(249,000)	(274,000)
Amortization of net loss	47,000	42,000
Net periodic (benefit) cost	(11,000)	$ (56,000)
Expected contribution to Pension Plan (minimum)			$ 500,000
Employer contributions made to the defined benefit plan	250,000
Anticipated additional contributions anticipated during the remainder of the year (at least)	$ 250,000