Components of Net Periodic Benefit Cost (Details Textual) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefits Plan Estimated Future Employer Contributions In Next Fiscal Year			$ 3,700
Defined Benefit Plan, Expected Future Benefit Payment, Remainder of Fiscal Year			736
Defined Contribution Plan Employer Accrued Discretionary Contribution Amount	$ 870	$ 726
Post Retirement Health Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefits Plan Estimated Future Employer Contributions In Next Fiscal Year			$ 251
Defined Benefit Plan, Plan Assets, Contributions by Employer	119
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 1,200