Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Operating Results [Abstract]
Revenues	$ 13,075	$ 15,556	$ 16,364	$ 12,346	$ 13,157	$ 16,902	$ 16,059	$ 11,291	$ 57,341	$ 57,409	$ 53,782
Operating expenses	13,517	13,681	13,958	12,853	13,117	14,556	13,808	12,480	54,009	53,961	53,988
Operating income (loss)	(442)	1,875	2,406	(507)	40	2,346	2,251	(1,189)	3,332	3,448	(206)
Net gain (loss) on dispositions of assets	1,996	2,928	(135)	13	(36)	63	(1)	(25)	4,802	1	(47)
Unrealized derivative gain (loss)	3,570	7,895	(4,710)	4,823	(212)	(4,615)	(11,718)	2,115	11,578	(14,430)	10,028
Other income (expense)	(8)	(4)	31	95	3	(12)	94	31	114	116	34
Interest expense	(1,310)	(1,118)	(1,490)	(1,527)	(1,697)	(1,774)	(1,819)	(1,729)	(5,445)	(7,019)	(5,399)
Loss on debt extinguishment	(102)	(104)	0	(7)	(18)	(37)	(94)	(9)	(213)	(158)	(458)
Impairment recovery (loss)	(311)	313	(3,053)	(777)	(1,388)	0	0	119	(3,828)	(1,269)	(2,438)
Earnings (loss) from continuing operations before income taxes	3,393	11,785	(6,951)	2,113	(3,308)	(4,029)	(11,287)	(687)	$ 10,340	$ (19,311)	$ 1,514
Income tax expense (benefit)
Earnings (loss) from continuing operations	3,393	11,785	(6,951)	2,113	(3,308)	(4,029)	(11,287)	(687)	$ 10,340	$ (19,311)	$ 1,514
Gain (loss) from discontinued operations, net of tax	1,424	169	1,052	1,337	413	1,628	829	182	3,982	3,052	(2,867)
Net earnings (loss)	4,817	11,954	(5,899)	3,450	(2,895)	(2,401)	(10,458)	(505)	14,322	(16,259)	(1,353)
(Earnings) loss attributable to noncontrolling interest	(476)	(724)	284	(281)	4	3	15	1	(1,197)	23	2
Net earnings (loss) attributable to controlling interests	4,341	11,230	(5,615)	3,169	(2,891)	(2,398)	(10,443)	(504)	13,125	(16,236)	(1,351)
Preferred stock dividends declared and undeclared	(925)	(914)	(902)	(891)	(879)	(868)	(858)	(847)	(3,632)	(3,452)	(3,349)
Net earnings (loss) attributable to common shareholders: Total Basic	$ 3,416	$ 10,316	$ (6,517)	$ 2,278	$ (3,770)	$ (3,266)	$ (11,301)	$ (1,351)	$ 9,493	$ (19,688)	$ (4,700)
Basic Earnings Per Share (EPS)
Basic EPS from continuing operations	$ 0.44	$ 2.06	$ (1.52)	$ 0.23					$ 1.22	$ (5.84)	$ (0.64)
Basic EPS from discontinued operations	0.25	0.03	0.20	0.25					0.72	0.79	(0.99)
Total Basic EPS	0.69	2.09	(1.32)	0.48					1.94	(5.05)	(1.63)
Diluted Earnings Per Share (EPS)
Diluted EPS from continuing operations	(0.04)	0.12	(1.52)	(0.14)					(0.15)	(5.84)	(0.64)
Diluted EPS from discontinued operations	0.05	0.01	0.20	0.05					0.15	0.79	(0.99)
Total EPS Diluted	$ 0.01	$ 0.13	$ (1.32)	$ (0.09)					$ 0.00	(5.05)	$ (1.63)
Basic and Diluted Earnings Per Share
EPS from continuing operations					$ (0.89)	$ (1.04)	$ (3.69)	$ (0.53)		(5.84)
EPS from discontinued operations					0.09	0.35	0.25	0.06		0.79
Total EPS basic and diluted					$ (0.80)	$ (0.69)	$ (3.44)	$ (0.47)		$ (5.05)