Discontinued Operations - Consolidated Statement of Comprehensive Income (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense	$ 1,953,626	$ 32,157	$ 2,327,099	$ 342,964
Net income from discontinued operations	3,394,981	34,825	4,044,776	581,652
EWW/Pipeline Assets [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	0	1,741,491	4,608,504	7,185,277
Cost of sales	0	(1,047,877)	(2,533,836)	(4,204,071)
Distribution, general & administrative	0	(345,758)	(779,610)	(1,129,945)
Maintenance	0	(42,372)	(80,708)	(130,788)
Depreciation & amortization	0	(178,554)	0	(541,777)
Taxes other than income	0	(62,236)	(168,588)	(233,612)
Other income	0	6,307	7,263	22,571
Interest expense	1,598	971	634	(281)
Pretax income from discontinued operations	1,598	71,972	1,053,659	967,374
Gain on the sale of EWW/Pipeline Assets	5,366,271	0	5,366,271	0
Income tax expense	(1,960,882)	(20,465)	(2,345,201)	(346,660)
Net income from discontinued operations	3,406,987	51,507	4,074,729	620,714
Independence [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income from discontinued operations	$ (12,006)	$ (16,682)	$ (29,953)	$ (39,062)