Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Before Tax		$ (115,429)	$ (222,402)	$ (399,046)
Other Comprehensive Income (Loss), Income Tax		37,235	83,602	153,032
Other Comprehensive Loss, Net of Tax		(78,194)	(138,800)	(246,014)
Foreign Currency Translation Adjustment [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax			(18,898)	(16,061)
Other Comprehensive Income (Loss) before Reclassifications, Tax			0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(22,149)	(18,898)	(16,061)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax			5,501	(404)
Reclassification from AOCI, Current Period, Tax			0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0	5,501	(404)
Other Comprehensive Income (Loss), Before Tax		(22,149)	(13,397)	(16,465)
Other Comprehensive Income (Loss), Income Tax		0	0	0
Other Comprehensive Loss, Net of Tax		(22,149)	(13,397)	(16,465)
Unrealized Gains (Losses) on Available- for- Sale Securities [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		55,507	10,620	62,719
Other Comprehensive Income (Loss) before Reclassifications, Tax		(22,203)	(4,248)	(25,088)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		33,304	6,372	37,631
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		1,879	(4)	(265,274)
Reclassification from AOCI, Current Period, Tax		(752)	2	106,110
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		1,127	(2)	(159,164)
Other Comprehensive Income (Loss), Before Tax		57,386	10,616	(202,555)
Other Comprehensive Income (Loss), Income Tax		(22,955)	(4,246)	81,022
Other Comprehensive Loss, Net of Tax		34,431	6,370	(121,533)
Pension and Other Postretirement Plans [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(80,349)	(126,132)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(16,417)	(9,580)	(29,819)
Reclassification from AOCI, Current Period, Tax		6,567	3,831	11,928
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(9,850)	(5,749)	(17,891)
Other Comprehensive Income (Loss), Before Tax		(150,332)	(219,800)	(180,893)
Other Comprehensive Income (Loss), Income Tax		60,133	87,919	72,357
Other Comprehensive Loss, Net of Tax		(90,199)	(131,881)	(108,536)
Net Actuarial Loss [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		(133,915)	(211,054)	(149,482)
Other Comprehensive Income (Loss) before Reclassifications, Tax		53,566	84,421	59,792
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(80,349)	(126,633)	(89,690)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	1,157	(9,906)	(29,412)
Reclassification from AOCI, Current Period, Tax		(463)	3,962	11,765
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		694	(5,944)	(17,647)
Net Prior Service Cost [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax				(1,600)
Other Comprehensive Income (Loss) before Reclassifications, Tax				640
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax				(960)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	419	275	(407)
Reclassification from AOCI, Current Period, Tax		(167)	(110)	163
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		252	165	(244)
Curtailment Gains Included in Net Income [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax				8
Other Comprehensive Income (Loss) before Reclassifications, Tax				(3)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax				5
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(17,993)	51	0
Reclassification from AOCI, Current Period, Tax		7,197	(21)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(10,796)	30
Curtailment And Settlement Included in Distribution [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax			834
Other Comprehensive Income (Loss) before Reclassifications, Tax			(333)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			501
Cash Flow Hedge [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(290)	29
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		13	79
Other Comprehensive Income (Loss), Before Tax		(334)	179	867
Other Comprehensive Income (Loss), Income Tax		57	(71)	(347)
Other Comprehensive Loss, Net of Tax		$ (277)	$ 108	$ 520

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension and postretirement plan cost (see Note 14).