Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ (796,124)	$ 111,834
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	320,572	324,671
Deferred income taxes	(140,031)	(10,769)
Reduction in value of assets including discontinued operations	807,637
Stock based and performance share unit compensation expense	24,943	22,118
Amortization of debt acquisition costs and note discount	3,881	4,113
Other reconciling items, net	(243)	(20,047)
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	349,926	(30,287)
Inventory and other current assets	5,273	17,041
Accounts payable	(85,195)	6,367
Accrued expenses	(69,908)	(7,570)
Income taxes	(33,280)	28,014
Other, net	46,065	(5,740)
Net Cash Provided by (Used in) Operating Activities, Total	433,516	439,745
Cash flows from investing activities:
Payments for capital expenditures	(240,305)	(315,233)
Purchase of Leased Vessel	46,442
Proceeds from Sale of Available-for-sale Securities, Equity		10,622
Other	(2,909)	9,865
Net Cash Provided by (Used in) Investing Activities, Total	(289,656)	(294,746)
Cash flows from financing activities:
Payment to Extinguish Capital Lease Obligation	20,933
Proceeds from issuance of long-term debt	6,946
Principal payments of long-term debt	(10,483)	(10,000)
Payments of Ordinary Dividends, Common Stock	24,021	25,216
Proceeds from exercise of stock options	8,800	10,328
Payments for purchase and retirement of Common Stock		(116,539)
Other	(3,718)	739
Net Cash Provided by (Used in) Financing Activities, Total	(43,409)	(140,688)
Payments on revolving line of credit	7,475	7,562
Proceeds From Revolving Line Of Credit	7,475	7,562
Effect of exchange rate changes on cash	6,765	1,295
Net increase in cash and cash equivalents	107,216	5,606
Cash and cash equivalents at beginning of period	393,046	196,047
Cash and cash equivalents at end of period	$ 500,262	$ 201,653