Retirement and Other Employee Benefits (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Qualified Pension Benefits - Plan 1
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 0	$ 9,750	$ 0	$ 19,500
Interest cost		3,400	9,050	6,800	18,100
Expected return on plan assets		(7,800)	(13,725)	(15,600)	(27,450)
Amortization of prior service cost		0	0	0	0
Amortization of net loss		0	3,325	0	6,650
Curtailment/settlement charge		0	0	(23,057)	0
Net periodic benefit (gain) cost		(4,400)	8,400	(31,857)	16,800
Qualified Pension Benefits - Plan 2
Defined Benefit Plan Disclosure [Line Items]
Service cost		0		0
Interest cost		3,500		7,000
Expected return on plan assets		(5,950)		(11,900)
Amortization of prior service cost		0		0
Amortization of net loss		325		650
Curtailment/settlement charge		0		0
Net periodic benefit (gain) cost		(2,125)		(4,250)
Nonqualified Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	[1]	100	1,125	200	2,250
Interest cost	[1]	925	1,350	1,850	2,700
Expected return on plan assets	[1]	0	0	0	0
Amortization of prior service cost	[1]	0	200	0	400
Amortization of net loss	[1]	300	725	600	1,450
Curtailment/settlement charge	[1]	0	400	(2,285)	800
Net periodic benefit (gain) cost	[1]	1,325	3,800	365	7,600
Retirement Health Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		0	625	0	1,250
Interest cost		875	950	1,750	1,900
Expected return on plan assets		(750)	(825)	(1,500)	(1,650)
Amortization of prior service cost		0	(225)	0	(450)
Amortization of net loss		0	0	0	0
Curtailment/settlement charge		0	0	(4,236)	0
Net periodic benefit (gain) cost		$ 125	$ 525	$ (3,986)	$ 1,050

[1] The Company’s nonqualified plan is unfunded.