CONSOLIDATED STATEMENTS OF CHANGES IN PARTNER'S CAPITAL - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Increase (Decrease) in Partners' Capital
Balance	$ (37,823,787)	$ (35,624,010)
Balance (in units)	121,978	124,386
Distribution to Partners	$ (1,169,173)	$ (1,177,353)
Stock Buyback	$ (389,947)	$ (2,930,736)
Stock Buyback (in units)	(219)	(1,795)
Net income	$ 1,368,783	$ 1,500,516
Balance	$ (38,014,124)	$ (38,231,583)
Balance (in units)	121,759	122,591
Subtotal
Increase (Decrease) in Partners' Capital
Balance (in units)	180,225	180,225
Balance (in units)	180,225	180,225
General Partnership
Increase (Decrease) in Partners' Capital
Balance	$ (376,827)	$ (354,833)
Balance (in units)	1,802	1,802
Distribution to Partners	$ (11,692)	$ (11,774)
Stock Buyback	(311,952)	(29,307)
Net income	13,688	15,005
Balance	$ (686,783)	$ (380,909)
Balance (in units)	1,802	1,802
Treasury Units
Increase (Decrease) in Partners' Capital
Balance (in units)	(58,247)	(55,839)
Stock Buyback (in units)	(219)	(1,795)
Balance (in units)	(58,466)	(57,634)
Class A
Increase (Decrease) in Partners' Capital
Balance	$ (30,287,245)	$ (28,527,352)
Balance (in units)	144,180	144,180
Distribution to Partners	$ (935,338)	$ (941,882)
Stock Buyback	(74,095)	(2,344,601)
Net income	1,095,026	1,200,413
Balance	$ (30,201,652)	$ (30,613,422)
Balance (in units)	144,180	144,180
Class B
Increase (Decrease) in Partners' Capital
Balance	$ (7,159,715)	$ (6,741,825)
Balance (in units)	34,243	34,243
Distribution to Partners	$ (222,143)	$ (223,697)
Stock Buyback	(3,900)	(556,828)
Net income	260,069	285,098
Balance	$ (7,125,689)	$ (7,237,252)
Balance (in units)	34,243	34,243