Employee Benefit Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost
Interest cost	1,712	1,786
Expected return on plan assets	(2,845)	(2,569)
Amortization of unrecognized prior service cost
Amortization of unrecognized net loss (gain)	451	475
Lump-sum settlement cost
Curtailment recognition
Contractual benefit charge		270
Total net periodic benefit cost	(682)	(38)
Postretirement Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	33	48
Interest cost	186	199
Expected return on plan assets
Amortization of unrecognized prior service cost	14	14
Amortization of unrecognized net loss (gain)	(282)	(317)
Lump-sum settlement cost
Curtailment recognition
Contractual benefit charge		150
Total net periodic benefit cost	$ (49)	$ 94