Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Employee benefit accruals	$ 17,335	$ 16,201
Impairment of investments	1,534	4,332
Impact of timing of settlement payments	28,266	39,840
Various U.S. state tax loss carryforwards	6,551	6,713
Other	2,803	0
Deferred tax assets	56,489	67,086
Less: Valuation allowance	(4,439)	(3,900)
Net deferred tax assets	52,050	63,186
Deferred tax liabilities:
Excess of tax basis over book-basis non-consolidated entities	(7,494)	(7,292)
Book/tax differences on fixed and Intangible assets	(54,776)	(52,598)
Capitalized interest expense	(8,673)	(4,080)
Book/tax differences on inventory	(16,143)	(16,891)
Book/tax differences on long-term investments	(23,937)	(29,701)
Impact of accounting for convertible debt	(27,362)	(30,494)
Book/tax differences on available for sale securities	(6,750)	0
Other	0	(1,559)
Deferred tax liabilities	(145,135)	(142,615)
Net deferred tax liabilities	$ (93,085)	$ (79,429)