Condensed Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows from Operating Activities:
Net Income (Loss)	$ (126,226)	$ (130,995)	$ 56,531
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	66,564	26,478	28,894
Impairment of oil and gas properties	53,072	65,706	7,692
Deferred tax expense (benefit)	(17,594)	21,116	(3,367)
Unrealized gains on derivatives	(5,141)	(8,378)	(12,291)
Gain on sales of reserves in place	0	0	(87,171)
Amortization of non-cash compensation	4,401	3,697	3,692
Amortization of loan costs and discount	14,179	12,234	10,262
Non-cash interest expense	8,684	12,811	8,764
Loss on early extinguishment of debt	21,661	402	0
Other	15,365	1,518	(2,086)
Changes in operating assets and liabilities:
(Increase) decrease in receivables	(24,319)	(531)	6,732
(Increase) decrease in other current assets	(592)	(13,328)	(4,668)
Increase (decrease) in liabilities	28,559	(30,073)	4,035
Net Cash Provided by (Used in) Operating Activities	38,613	(39,343)	17,019
Cash Flows From Investing Activities:
Capital expenditures	(246,925)	(165,062)	(92,007)
Acquisitions, net of cash acquired	(238,854)	(33,075)	(43,726)
Proceeds from sales, net of cash	1,407	0	108,316
(Increase) Decrease in restricted cash	(178)	31,726	(28,897)
Net Cash Used in Investing Activities	(484,550)	(166,411)	(56,314)
Cash Flows From Financing Activities:
Repayments of borrowings	(274,629)	(103,225)	(75,342)
Borrowings under debt agreements, net of debt discount	654,023	210,000	185,000
Proceeds from issuance of common stock	60,805	118,444	30,181
Dividends paid	(1,665)	(1,816)	(2,070)
Payments for early extinguishment of debt	(7,248)	0	0
Financing costs paid	(32,204)	(11,401)	(26,590)
Other financing	4	521	96
Net Cash Provided by Financing Activities	399,086	212,523	111,275
Net Increase (Decrease) in Cash and Cash Equivalents	(46,851)	6,769	71,980
Cash and Cash Equivalents, Beginning of Period	106,036	99,267	27,287
Cash and Cash Equivalents, End of Period	$ 59,185	$ 106,036	$ 99,267