Pensions and Other Employee Benefits Plans (Components of Net Periodic Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	$ 176	$ 176	$ 528	$ 528
Interest cost	[2]	377	441	1,130	1,324
Expected return on plan assets	[2]	(684)	(663)	(2,051)	(1,989)
Amortization of net actuarial loss (gain)	[2]	370	322	1,110	966
Net periodic cost		239	276	717	829
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	0	0	0	0
Interest cost	[2]	3	4	9	12
Expected return on plan assets	[2]	0	0	0	0
Amortization of net actuarial loss (gain)	[2]	0	(1)	0	(3)
Net periodic cost		$ 3	$ 3	$ 9	$ 9

[1] Included in general and administrative expenses.

[2] Included in other expense.