Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Employee benefit accruals	$ 12,801	$ 11,621
Impairment of investments	4,131	1,834
Impact of timing of settlement payments	20,551	14,367
Disallowed interest expense carryforward	1,619	0
Various U.S. state tax loss carryforwards	5,137	6,556
Other	1,966	1,110
Deferred tax assets	46,205	35,488
Less: Valuation allowance	(3,817)	(3,664)
Net deferred tax assets	42,388	31,824
Deferred tax liabilities:
Basis differences on non-consolidated entities	(7,752)	(5,388)
Basis differences on fixed and intangible assets	(35,854)	(36,712)
Capitalized interest expense	(6,532)	(6,069)
Basis differences on inventory	(11,497)	(11,357)
Basis differences on long-term investments	(16,496)	(15,521)
Impact of accounting for convertible debt	(385)	(12,776)
Basis differences on available for sale securities	(1,283)	(2,802)
Deferred tax liabilities	(79,799)	(90,625)
Net deferred tax liabilities	$ (37,411)	$ (58,801)