Accumulated Other Comprehensive Income (Loss) (Components of OCI) (Details 1) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before tax		$ 10,509	$ 21,399
Other Comprehensive Income (Loss), income tax		303	(3,117)
Other Comprehensive Income (Loss), Net of Tax		10,812	18,282
Foreign Currency Translation Adjustment [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		11,564	13,668
Other Comprehensive Income (Loss) before Reclassifications, Tax		0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		11,564	13,668
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0
Other Comprehensive Income (Loss), Net of Tax		11,564
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax		0	9,558
Other Comprehensive Income (Loss) before Reclassifications, Tax		0	(3,823)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		0	5,735
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		(1,291)	(1,703)
Reclassification from AOCI, Current Period, Tax		348	681
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(943)	(1,022)
Other Comprehensive Income (Loss), before tax		(1,291)	(1,703)
Other Comprehensive Income (Loss), income tax		348	681
Other Comprehensive Income (Loss), Net of Tax		(943)	(1,022)
Net Prior Service Cost [Member]
Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	76	120
Reclassification from AOCI, Current Period, Tax		(21)	(48)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		55	72
Net Actuarial (Gain) Loss [Member]
Other Comprehensive Income (Loss) [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	[1]	(1,367)	(1,823)
Reclassification from AOCI, Current Period, Tax		369	729
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(998)	(1,094)
Cash Flow Hedge [Member]
Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		189
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		2
Other Comprehensive Income (Loss), before tax		236	(124)
Other Comprehensive Income (Loss), income tax		(45)	25
Other Comprehensive Income (Loss), Net of Tax		$ 191	$ (99)

[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.