Pensions and Other Employee Benefits Plans (Components of Net Periodic Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 171	$ 183	$ 352	$ 361
Interest cost	[2]	443	499	883	1,009
Expected return on plan assets	[2]	(657)	(609)	(1,326)	(1,216)
Amortization of net actuarial loss (gain)	[2]	341	272	644	503
Net periodic cost		298	345	553	657
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	0	0	0	0
Interest cost	[2]	4	5	8	10
Expected return on plan assets	[2]	0	0	0	0
Amortization of net actuarial loss (gain)	[2]	(1)	(1)	(2)	(2)
Net periodic cost		$ 3	$ 4	$ 6	$ 8

[1] Included in general and administrative expenses.

[2] Included in other expense.