Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 5,685	$ 16,631
Restricted cash	1,688	1,638
Oil and gas revenue receivable	64,123	86,487
Joint interest billing and other receivables	20,865	16,616
Derivative assets	14,480	16,865
Income tax receivable	6,431	10,091
Inventory	17,747	13,450
Other current assets	3,143	5,647
Total current assets	134,162	167,425
Oil and gas properties, net, using the full cost method of accounting:
Proven	1,485,980	1,325,068
Property, plant and equipment, net	10,887	9,569
Other assets	10,831	10,920
Total assets	1,641,860	1,512,982
Current liabilities:
Accounts payable	41,426	59,951
Accrued liabilities	75,806	80,268
Production taxes payable	55,048	51,352
Current portion of long-term debt	2,438
Interest payable	20,759	24,406
Derivative liabilities	54,891
Capital cost accrual	18,030	32,513
Total current liabilities	268,398	248,490
Long-term debt	2,176,408	2,116,211
Deferred gain on sale of liquids gathering system	99,912	105,189
Other long-term obligations	211,968	197,728
Total liabilities	2,756,686	2,667,618
Commitments and contingencies (Note 9)
Shareholders' equity:
Common stock - no par value; authorized - unlimited; issued and outstanding - 197,053,583 and 196,346,736 at June 30, 2018 and December 31, 2017, respectively	2,129,191	2,116,018
Treasury stock	(49)	(49)
Retained loss	(3,243,968)	(3,270,605)
Total shareholders' deficit	(1,114,826)	(1,154,636)
Total liabilities and shareholders' equity	$ 1,641,860	$ 1,512,982