CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL (USD $)	Total USD ($)	Subtotal	Class A USD ($)	Class B USD ($)	General Partnership USD ($)	Treasury Units
Balance at Dec. 31, 2009	$ (21,332,823)		$ (17,069,520)	$ (4,050,138)	$ (213,165)
Balance (in units) at Dec. 31, 2009	132,346	180,225	144,180	34,243	1,802	47,879
Increase (Decrease) in Partners' Capital
Distributions to Partners	(3,687,600)		(2,950,080)	(700,644)	(36,876)
Stock buyback	(540,911)		(432,920)	(102,591)	(5,400)
Stock Buyback (in units)	(862)					862
Net income (loss)	(1,359,232)		(1,087,386)	(258,254)	(13,592)
Balance at Dec. 31, 2010	(26,920,566)		(21,539,906)	(5,111,627)	(269,033)
Balance (in units) at Dec. 31, 2010	131,484	180,225	144,180	34,243	1,802	48,741
Increase (Decrease) in Partners' Capital
Distributions to Partners	(3,681,566)		(2,945,253)	(699,498)	(36,815)
Net income (loss)	9,291,281		7,433,025	1,765,343	92,913
Balance at Dec. 31, 2011	(21,310,851)		(17,052,134)	(4,045,782)	(212,935)
Balance (in units) at Dec. 31, 2011	131,484	180,225	144,180	34,243	1,802	48,741
Increase (Decrease) in Partners' Capital
Distributions to Partners	(3,932,410)		(3,145,928)	(747,158)	(39,324)
Stock buyback	(906,214)		(726,058)	(171,148)	(9,008)
Stock Buyback (in units)	(1,040)			198		1,040
Net income (loss)	3,633,798		2,907,038	690,422	36,338
Balance at Dec. 31, 2012	$ (22,515,677)		$ (18,017,082)	$ (4,273,666)	$ (224,929)
Balance (in units) at Dec. 31, 2012	130,444	180,225	144,180	34,243	1,802	49,781