Discontinued Operations Income Statement and Balance Sheet (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assets of Disposal Group, Including Discontinued Operation [Abstract]
Accounts receivable	$ 4,101												$ 4,101
Inventories	68												68
Oil and gas properties	348,379												348,379
Less accumulated depreciation, depletion and amortization	(301,609)												(301,609)
Other property, net	165												165
Total assets held-for-sale	51,104												51,104
Liabilities of Disposal Group, Including Discontinued Operation [Abstract]
Accounts payable	(1,743)												(1,743)
Royalty payable	(1,419)												(1,419)
Other current liabilities	(400)												(400)
Other long-term liabilities	(14,983)												(14,983)
Total liabilities held-for-sale	(18,545)												(18,545)
Total held-for-sale properties	32,559												32,559
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Oil and gas revenues	0	[1]	0	[1]	(18,562)	[1]	(18,663)	[1]	(18,749)	(18,895)	(18,451)	(20,255)	60,191	76,350	110,366
Pretax income (loss) from discontinued operations													10,028	(2,373)	54,698
Income tax expense (benefit)													2,215	(715)	19,379
Income (Loss) From Discontinued Operations													7,813	(1,658)	35,319
Gain on disposal of discontinued operations, net													5,605	0	0
Income tax expense													2,011	0	0
Gain on Disposal of Discontinued Operations, net													3,594	0	0
Total Income (Loss) From Discontinued Operations													11,407	(1,658)	35,319
Income (Loss) from Discontinued Operations (in dollars per share)													$ 0.10	$ (0.02)	$ 0.49
Gain on Disposal of Discontinued Operations (in dollars per share)													$ 0.05	$ 0.00	$ 0.00
Total Income (Loss) From Discontinued Operations (in dollars per share)													$ 0.15	$ (0.02)	$ 0.49
Income (Loss) from Discontinued Operations (in dollars per share)													$ 0.11	$ (0.02)	$ 0.49
Gain on Disposal of Discontinued Operations (in dollars per share)													$ 0.05	$ 0.00	$ 0.00
Total Income (Loss) From Discontinued Operations (in dollars per share)													$ 0.16	$ (0.02)	$ 0.49
Black Warrior Basin
Assets of Disposal Group, Including Discontinued Operation [Abstract]
Accounts receivable	2,829												2,829
Inventories	0												0
Oil and gas properties	0												0
Less accumulated depreciation, depletion and amortization	0												0
Other property, net	0												0
Total assets held-for-sale	2,829												2,829
Liabilities of Disposal Group, Including Discontinued Operation [Abstract]
Accounts payable	(1,732)												(1,732)
Royalty payable	(550)												(550)
Other current liabilities	(379)												(379)
Other long-term liabilities	0												0
Total liabilities held-for-sale	(2,661)												(2,661)
Total held-for-sale properties	168												168
North Louisiana/East Texas
Assets of Disposal Group, Including Discontinued Operation [Abstract]
Accounts receivable	1,272												1,272
Inventories	68												68
Oil and gas properties	348,379												348,379
Less accumulated depreciation, depletion and amortization	(301,609)												(301,609)
Other property, net	165												165
Total assets held-for-sale	48,275												48,275
Liabilities of Disposal Group, Including Discontinued Operation [Abstract]
Accounts payable	(11)												(11)
Royalty payable	(869)												(869)
Other current liabilities	(21)												(21)
Other long-term liabilities	(14,983)												(14,983)
Total liabilities held-for-sale	(15,884)												(15,884)
Total held-for-sale properties	$ 32,391												$ 32,391

[1] As discussed in Note 13, Discontinued Operations, during the fourth quarter of 2013, the Company completed the sale of its Black Warrior Basin coalbed methane properties in Alabama. The property was classified as held-for-sale and reflected in discontinued operations during the third quarter of 2013. Also, during the third quarter of 2013, the Company classified its North Louisiana/East Texas natural gas and oil properties as held-for-sale and reflected the associated operating results in discontinued operations.