Pensions and Other Employee Benefits Plans (Components of Net Periodic Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 178	$ 192	$ 351	$ 334
Interest cost	494	501	980	991
Expected return on plan assets	(530)	(511)	(1,062)	(1,023)
Amortization of net actuarial loss	267	248	499	444
Net periodic cost	409	430	768	746
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1	1
Interest cost	4	5	9	10
Amortization of net actuarial loss	1	2	2	3
Amortization of prior service credits	6	5	12	11
Net periodic cost	$ 12	$ 13	$ 24	$ 25