Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Cash Flows from Operating Activities:
Net Income	$ 3,570	[1]	$ 20,181
Plus loss from discontinued operations, net of taxes			68
Adjustments to reconcile net income to net cash provided by operation activities -
Depreciation, depletion, and amortization	61,363		52,921
Accretion of asset retirement obligation	1,112		1,136
Deferred income taxes	2,312		10,822
Stock-based compensation expenses	3,629		2,684
Other	(2,889)		(8,589)
Change in assets and liabilities-
(Increase) decrease in accounts receivable	3,193		(13,612)
Decrease in accounts payable and accrued liabilities	(7,913)		(3,112)
Increase in income taxes payable			2
Decrease in accrued interest	(594)		(785)
Cash provided by operating activities - continuing operations	63,783		61,716
Cash provided by operating activities - discontinued operations			99
Net Cash Provided by Operating Activities	63,783		61,815
Cash Flows from Investing Activities:
Additions to property and equipment	(187,915)		(131,911)
Proceeds from the sale of property and equipment	532		13
Cash used in investing activities - continuing operations	(187,383)		(131,898)
Cash provided by investing activities - discontinued operations			5,000
Net Cash Used in Investing Activities	(187,383)		(126,898)
Cash Flows from Financing Activities:
Net proceeds from issuances of common stock	1,329		1,742
Purchase of treasury shares	(2,636)		(3,262)
Cash used in financing activities - continuing operations	(1,307)		(1,520)
Cash provided by financing activities - discontinued operations
Net Cash Used in Financing Activities	(1,307)		(1,520)
Net Decrease in Cash and Cash Equivalents	(124,907)		(66,603)
Cash and Cash Equivalents at Beginning of Period	251,696		86,367
Cash and Cash Equivalents at End of Period	126,789		19,764
Supplemental Disclosures of Cash Flows Information:
Cash paid during period for interest, net of amounts capitalized	13,415		8,741
Cash paid during period for income taxes			$ 1,420

[1] (2) Unaudited