Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows from Operating Activities:
Net Income	$ 22,817	$ 9,720
Adjustments to reconcile net income to net cash provided by operation activities -
Depreciation, depletion, and amortization	186,526	181,638
Accretion of asset retirement obligation	4,732	3,465
Deferred income taxes	15,162	8,239
Stock-based compensation expenses	8,454	10,562
Other	(3,796)	(583)
Decrease in accounts receivable	(3,696)	14,385
Increase (decrease) in accounts payable and accrued liabilities	3,873	(3,051)
Decrease in income taxes payable	(208)	(248)
Increase (decrease) in accrued interest	(8,257)	(443)
Net Cash Provided by Operating Activities	225,607	223,684
Cash Flows from Investing Activities:
Additions to property and equipment	(435,722)	(575,711)
Proceeds from the sale of property and equipment	6,990	523
Net Cash Used in Investing Activities	(428,732)	(575,188)
Cash Flows from Financing Activities:
Proceeds from Lines of Credit	203,600	102,640
Net proceeds from issuances of common stock	946	1,599
Purchase of treasury shares	(1,494)	(2,781)
Net Cash Used in Financing Activities	203,052	101,458
Net Decrease in Cash and Cash Equivalents	(73)	(250,046)
Cash and Cash Equivalents at Beginning of Period	170	251,696
Cash and Cash Equivalents at End of Period	97	1,650
Supplemental Disclosures of Cash Flows Information:
Cash paid during period for interest, net of amounts capitalized	57,990	39,175
Cash paid during period for income taxes	$ 208	$ 248