Consolidated Statements of Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Oil and natural gas sales	$ 63,424	$ 82,716	$ 136,276
Sales of purchased natural gas	5,038	2,189	2,127
Other	133	159	427
Total revenues	68,595	85,064	138,830
Costs and expenses:
Production	12,368	12,873	18,193
Exploration, abandonment and impairment	5,963	21,544	19,864
Cost of purchased natural gas	4,418	2,082	2,055
Seismic and other exploration	104	370	4,285
Revaluation of contingent consideration			(2,500)
General and administrative	16,320	24,138	31,071
Depreciation, depletion and amortization	29,025	37,707	48,594
Accretion of asset retirement obligations	373	368	406
Total costs and expenses	68,571	99,082	121,968
Operating (loss) income	24	(14,018)	16,862
Other income (expense):
Interest and other expense	(11,841)	(13,077)	(6,044)
Interest and other income	2,546	855	1,124
(Loss) gain on commodity derivative contracts	(3,257)	27,457	37,454
Foreign exchange loss	(3,871)	(5,653)	(6,523)
Total other income (expense)	(16,423)	9,582	26,011
Income (loss) from continuing operations before income taxes	(16,399)	(4,436)	42,873
Current income tax expense	(6,071)	(3,587)	(1,784)
Deferred income tax benefit (expense)	(25)	18,642	11,875
Net (loss) income from continuing operations	(22,445)	(26,665)	29,214
Income (loss) from discontinued operations before income taxes	15,998	(97,042)	(750)
Income tax benefit	204	16,169	612
Net income (loss) from discontinued operations	16,202	(80,873)	(138)
Net (loss) income	(6,243)	(107,538)	29,076
Other comprehensive (loss) income:
Foreign currency translation adjustment	(18,726)	(42,280)	(14,325)
Comprehensive (loss) income	$ (24,969)	$ (149,818)	$ 14,751
Basic net income (loss) per common share
Continuing operations	$ (0.51)	$ (0.65)	$ 0.77
Discontinued operations	$ 0.37	$ (1.98)
Weighted average common shares outstanding	43,885	40,841	37,829
Diluted net income (loss) per common share
Continuing operations	$ (0.51)	$ (0.65)	$ 0.77
Discontinued operations	$ 0.37	$ (1.98)
Weighted average common and common equivalent shares outstanding	43,885	40,841	38,031