Oil and Gas Producing Activities (Unaudited) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property acquisition costs [Abstract]
Unproved	$ 1,144,000	$ 1,444,000	$ 1,965,000
Proved	0	0	0
Exploration costs [Abstract]
Expensed	5,054,000	1,619,000	1,151,000
Capitalized	0	0	0
Development costs	1,745,000	10,160,000	20,219,000
Total costs incurred	7,943,000	13,223,000	23,335,000
Capitalized costs relating to oil and gas producing activities [Abstract]
Unproved oil and gas properties	3,104,000	7,578,000
Proved oil and gas properties	85,557,000	91,369,000
Gross capitalized cost	88,661,000	98,947,000
Accumulated depreciation, depletion and amortization	(64,682,000)	(64,169,000)
Net capitalized cost	23,979,000	34,778,000
Components of proved oil and gas reserves [Abstract]
Period of average estimated price of proved reserves	12 months
Standardized measure of discounted future net cash flows [Abstract]
Future gross revenues	58,885,000	64,495,000	59,793,000
Future costs [Abstract]
Lease operating expenses	(16,421,000)	(19,207,000)	(16,357,000)
Development costs	(1,068,000)	(119,000)	(299,000)
Future net cash flows before income taxes	41,396,000	45,169,000	43,137,000
Discount at 10% per annum	(17,175,000)	(17,729,000)	(17,976,000)
Discounted future net cash flows before income taxes	24,221,000	27,440,000	25,161,000
Future income taxes, net of discount at 10% per annum	(8,477,000)	(9,604,000)	(8,806,000)
Standardized measure of discounted future net cash flows	15,744,000	17,836,000	16,355,000
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average domestic crude oil realized	54
Effect of income taxes and discounting on the standardized measure of discounted future net cash flows [Abstract]
Future net cash flows before income taxes	41,396,000	45,169,000	43,137,000
Future income taxes	(14,489,000)	(15,809,000)	(15,098,000)
Future net cash flows	26,907,000	29,360,000	28,039,000
Discount at 10% per annum	(11,163,000)	(11,524,000)	(11,684,000)
Standardized measure of discounted future net cash flows	15,744,000	17,836,000	16,355,000
Principal sources of changes in the standardized measure of discounted future net flows [Abstract]
Beginning of year	17,836,000	16,355,000	20,931,000
Sale of oil and gas reserves	(981,000)	0	(3,802,000)
Net change in prices and production costs	(72,000)	9,341,000	(5,313,000)
New field discoveries and extensions, net of future production costs	4,456,000	9,767,000	9,513,000
Sales of oil and gas produced, net of production costs	(6,590,000)	(8,373,000)	(8,953,000)
Net change due to revisions in quantity estimates	2,460,000	(3,624,000)	(940,000)
Accretion of discount	1,773,000	1,797,000	1,944,000
Production rate changes and other	(4,265,000)	(6,629,000)	511,000
Net change in income taxes	1,127,000	(798,000)	2,464,000
End of year	15,744,000	17,836,000	16,355,000
Results of operations for oil and gas producing activities [Abstract]
Revenues	13,361,000	14,129,000	15,954,000
Costs and expenses [Abstract]
Production	(6,771,000)	(5,756,000)	(7,091,000)
Producing property impairment	(4,001,000)	(1,373,000)	(4,699,000)
Exploration	(5,054,000)	(1,619,000)	(1,151,000)
Oil and natural gas property sale gain	2,528,000	0	2,203,000
Depreciation, depletion and amortization	(7,573,000)	(7,494,000)	(8,848,000)
Operating income (loss) before income taxes	(7,510,000)	(2,113,000)	(3,632,000)
Income tax benefit	2,628,000	739,000	1,271,000
Operating income (loss)	$ (4,882,000)	$ (1,374,000)	$ (2,361,000)
Crude Oil [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average sales prices	89.60	94.99	93.85
Natural Gas [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average sales prices	5.42	4.69	3.51
Oil [Member]
Total proved reserves [Abstract]
Beginning of year	368,000	307,000	292,000
Revisions of previous estimates	6,000	(17,000)	29,000
Oil and gas reserves sold	(11,000)	0	(54,000)
Extensions, discoveries and other reserve additions	82,000	180,000	138,000
Production	(127,000)	(102,000)	(98,000)
End of year	318,000	368,000	307,000
Components of proved oil and gas reserves [Abstract]
Proved developed reserves	299,000	367,000	306,000
Proved undeveloped reserves	19,000	1,000	1,000
Total proved reserves	318,000	368,000	307,000
Natural Gas [Member]
Total proved reserves [Abstract]
Beginning of year	6,286,000	8,837,000	9,661,000
Revisions of previous estimates	724,000	(1,438,000)	(507,000)
Oil and gas reserves sold	(558,000)	(28,000)	(104,000)
Extensions, discoveries and other reserve additions	292,000	523,000	2,395,000
Production	(1,133,000)	(1,608,000)	(2,608,000)
End of year	5,611,000	6,286,000	8,837,000
Components of proved oil and gas reserves [Abstract]
Proved developed reserves	5,482,000	6,157,000	8,708,000
Proved undeveloped reserves	129,000	129,000	129,000
Total proved reserves	5,611,000	6,286,000	8,837,000