Income Taxes (Deferred Income Taxes Components) (Details 4) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Income Tax Liabilities [Line Items]
Employee benefit obligations	$ 68,392	$ 84,148
Accounts receivable	4,449	5,481
State income tax loss carryforwards	34,107	35,434
U.S. Federal income tax loss carryforwards	2,100	2,857
Non-U.S. income tax loss carryforwards	15,868	18,797
Other	14,657	26,546
Deferred tax assets	145,262	178,121
Valuation allowance	(33,120)	(48,742)
Deferred tax assets, net	112,142	129,379
Unrealized gain on available-for-sale securities	51,242	70,827
Goodwill and other intangible assets	88,798	109,428
Property, plant and equipment	9,997	11,248
Non-U.S. withholding tax	1,726	1,606
Deferred tax liabilities	421,175	476,713
Deferred Income Tax Liabilities, Net	309,033	347,334
non-U.S. [Member]
Deferred Income Tax Liabilities [Line Items]
Capital loss carryforwards	3,609	2,336
Non-U.S. income tax loss carryforwards	15,900
Valuation allowance	(9,900)
U.S. Federal [Member]
Deferred Income Tax Liabilities [Line Items]
U.S. Federal income tax loss carryforwards	2,100
U.S Federal foreign income tax credit carryforwards	987	2,522
State [Member]
Deferred Income Tax Liabilities [Line Items]
State income tax loss carryforwards	34,100
Capital loss carryforwards	1,093	0
Valuation allowance	(22,200)
Pension Plan [Member]
Deferred Income Tax Liabilities [Line Items]
Prepaid pension cost	$ 269,412	$ 283,604