CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income	$ 2,829	$ 3,811
Adjustments to reconcile net income to net cash provided by operating activities:
Accretion of discount on available-for-sale debt securities	(15)	(14)
Amortization of deferred offering costs	52	51
Depreciation, depletion and amortization	11,570	10,105
Change in fair value of derivative financial instruments	1,466	(1,087)
Stock option expense	315	383
Deferred tax expense	7	17
Change in assets and liabilities:
Decrease (increase) in accounts receivable-trade	(1,537)	515
Increase in other assets	(57)	(724)
Increase in accounts payable and accruals	2,142	692
Decrease in other long-term liabilities	(751)	(858)
Net cash provided by operating activities	16,021	12,891
Cash flows from investing activities:
Purchase, exploration and development of oil and gas properties	(2,824)	(26,012)
Purchase of property and equipment	(1,118)	(293)
Net cash used in investing activities	(3,942)	(26,305)
Cash flows from financing activities:
Proceeds from line of credit		10,000
Payments on debt and debentures	(10,000)	(38)
Proceeds from the exercise of stock options	191
Issuance of common stock, net		37
Net cash provided by (used in) financing activities	(9,809)	9,999
Net increase (decrease) in cash and cash equivalents	2,270	(3,415)
Cash and cash equivalents at beginning of period	8,475	10,614
Cash and cash equivalents at end of period	10,745	7,199
Supplemental disclosure of cash flow information
Cash paid for interest, net of amounts capitalized	668	738
Noncash investing and financing activities
Accrued preferred stock dividend	$ 3	$ 3