Post-retirement Plan (Net Periodic Pension Expense) (Details) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 635	$ 1,104
Interest cost on projected benefit obligations	349	562
Expected Return on Plan Assets	(511)	(865)
Net periodic pension expense	$ 473	801
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost		412	$ 350
Interest cost on projected benefit obligations		234	220
Amortization of prior service Credit		(870)	(870)
Net periodic post-retirement credit		$ (224)	$ (300)