Pensions and Other Employee Benefits Plans (Components of Net Periodic Cost) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 178	$ 187
Interest cost	[2]	510	464
Expected return on plan assets	[2]	(607)	(657)
Amortization of net actuarial loss (gain)	[2]	231	263
Net periodic cost		312	257
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	[2]	5	4
Amortization of prior service cost (credit)	[2]		6
Amortization of net actuarial loss (gain)	[2]	(1)
Net periodic cost		$ 4	$ 10

[1] Included in general and administrative expenses.

[2] Included in other expense.