Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Statement of Cash Flows [Abstract]
Net Cash Provided by Operating Activities	$ 60,242	$ 142,784
Cash Flows from Investing Activities
Purchases of property and equipment	294,115	227,244
Cash settlements on derivative transactions, net	31	0
Proceeds from disposition of property and equipment	146,195	95,396
Investments in and advances to 50% or less owned companies	12,666	43,760
Return of investments and advances from 50% or less owned companies	8,361	47,175
Net borrowings on revolving credit line to 50% or less owned companies	(1,099)	242
(Issuances of) payments received on third party leases and notes receivable, net	(1,320)	(4,416)
Net (increase) decrease in restricted cash	3,364	(16,435)
Net decrease in construction reserve funds	(93,543)	(24,552)
Net cash used in investing activities	(64,496)	(91,620)
Cash Flows from Financing Activities
Payments on long-term debt and capital lease obligations	156,321	156,632
Net repayments on inventory financing arrangements	0	(2,661)
Proceeds from issuance of long term debt, net of issue costs	114,763	197,585
Purchase of conversion option in convertible debt	7,096	0
Common stock acquired for treasury	2,396	65,214
Proceeds and tax benefits from share award plans	1,618	4,103
Issuance of noncontrolling interests, net of issue costs	0	400
Distributions to noncontrolling interests	(3,705)	(4,717)
Net cash used in financing activities	(53,137)	(27,136)
Effect of Exchange Rate Changes on Cash and Cash Equivalents	(1,438)	(1,406)
Net Increase (Decrease) in Cash and Cash Equivalents	(58,829)	22,622
Cash and Cash Equivalents, Beginning of Period	530,009	434,183
Cash and Cash Equivalents, End of Period	$ 471,180	$ 456,805