Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before tax		$ (6,076)	$ 57,785	$ (29,587)	$ 101,331
Other Comprehensive Income (Loss), income tax		874	(18,540)	1,976	(26,665)
Other Comprehensive Income (Loss), Net of Tax		(5,202)	39,245	(27,611)	74,666
Foreign Currency Translation Adjustment [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		(2,844)	11,470	(22,447)	34,776
Other Comprehensive Income (Loss) before Reclassifications, Tax		0	0	0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(2,844)	11,470	(22,447)	34,776
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				0
Other Comprehensive Income (Loss), Net of Tax				(22,447)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		0	47,836	0	71,370
Other Comprehensive Income (Loss) before Reclassifications, Tax		0	(19,134)	0	(28,548)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		0	28,702	0	42,822
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				0
Other Comprehensive Income (Loss), Net of Tax				0
Pension and Other Postretirement Plans [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax				0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(3,226)	(1,449)	(7,741)	(4,600)
Reclassification from AOCI, Current Period, Tax		873	580	2,090	1,840
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(2,353)	(869)	(5,651)	(2,760)
Other Comprehensive Income (Loss), before tax		(3,226)	(1,449)	(7,741)	(4,600)
Other Comprehensive Income (Loss), income tax		873	580	2,090	1,840
Other Comprehensive Income (Loss), Net of Tax		(2,353)	(869)	(5,651)	(2,760)
Net Prior Service Cost [Member]
Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	69	118	215	358
Reclassification from AOCI, Current Period, Tax		(18)	(47)	(58)	(143)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		51	71	157	215
Net Actuarial (Gain) Loss [Member]
Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(3,295)	(1,567)	(7,956)	(4,958)
Reclassification from AOCI, Current Period, Tax		891	627	2,148	1,983
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(2,404)	(940)	(5,808)	(2,975)
Cash Flow Hedge [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax				569
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				(82)
Other Comprehensive Income (Loss), before tax		(6)	(72)	601	(215)
Other Comprehensive Income (Loss), income tax		1	14	(114)	43
Other Comprehensive Income (Loss), Net of Tax		$ (5)	$ (58)	$ 487	$ (172)

[1] These accumulated other comprehensive income components are components of net periodic pension and postretirement plan cost (see Note 12) and are included in non-operating pension and postretirement benefit income in the Company’s Condensed Consolidated Statements of Operations.