Summary of Unaudited Quarterly Results of Operations - Summary of Unaudited Quarterly Results of Operations (Details) - USD ($)	3 Months Ended	12 Months Ended
Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenues and other income	$ 26,015,349	$ 30,052,544	$ 15,785,165	$ 16,458,034	$ 32,472,818	$ 16,234,830	$ 16,218,225	$ 23,208,975
Income from continuing operations	13,914,049	17,883,055	3,338,121	6,004,304	15,647,453	3,545,483	4,109,400	7,360,515
Net income	$ 13,914,049	$ 17,883,055	$ 3,338,121	$ 6,004,304	$ 15,647,453	$ 3,545,483	$ 4,109,400	$ 7,360,515
Income from continuing operations, per BUC	$ 0.22	$ 0.25	$ 0.04	$ 0.09	$ 0.23	$ 0.05	$ 0.06	$ 0.10
Net income, basic and diluted, per BUC	$ 0.22	$ 0.25	$ 0.04	$ 0.09	$ 0.23	$ 0.05	$ 0.06	$ 0.10	$ 0.60	$ 0.44	$ 0.34

Revenue and other income.

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- Definition

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109260490&loc=d3e1337-109256

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Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683

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The amount of net income (loss) from continuing operations per each basic and diluted share of common stock or unit when the per share amount is the same for both basic and diluted shares.

+ References

No definition available.

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The net result for the period of deducting operating expenses from operating revenues.

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