TREASURY UNITS (Details)				1 Months Ended			3 Months Ended	132 Months Ended	139 Months Ended
	Mar. 10, 2015 shares	Aug. 31, 2007 $ / item shares	Aug. 20, 2007 shares	May 03, 2019 USD ($) $ / item shares	Apr. 30, 2019 USD ($) shares	Sep. 30, 2007 $ / item shares	Mar. 31, 2019 USD ($) $ / item shares	Dec. 31, 2018 $ / item shares	Mar. 31, 2019 USD ($) $ / item shares	Mar. 06, 2008 shares
Treasury units							57,634		57,634
Period for repurchase of depository receipts	5 years		12 months
Depository receipts authorized to be repurchased	2,000,000		300,000							1,500,000
Number of depository receipts repurchased		1,408				1,408	1,408	1,408
Repurchase price of depository receipts (in dollars per receipt) | $ / item									27.97
Units required to be repurchased (in shares)							1,795
Total cost of repurchase | $							$ 2,930,736		$ 43,205,000
Subsequent event
Number of depository receipts repurchased				1,540
Repurchase price of depository receipts (in dollars per receipt) | $ / item				64.91
Total cost of repurchase | $				$ 96,861
General Partnership
Treasury units							577		577
Fixed distribution percentage of unit holders							1.00%
Number of depository receipts repurchased		180				180	180	180
Units required to be repurchased (in shares)							18
Total cost of repurchase | $							$ 29,307
Value of units required to be repurchased | $							$ 29,307
General Partnership | Subsequent event
Units required to be repurchased (in shares)					1
Value of units required to be repurchased | $					$ 1,249
Treasury Units
Units required to be repurchased (in shares)							1,795
Class A
Treasury units							46,107		46,107
Fixed distribution percentage of unit holders							80.00%
Repurchase price of units (in dollars per unit) | $ / item		839.10				839.10	839.10	839.10
Total cost of repurchase | $							$ 2,344,601
Class B
Treasury units							10,950		10,950
Fixed distribution percentage of unit holders							19.00%
Number of depository receipts repurchased		3,413				3,413	3,413	3,413
Total cost of repurchase | $							$ 556,828
Class B | Subsequent event
Units required to be repurchased (in shares)					12
Value of units required to be repurchased | $					$ 23,740
Class B
Value of units required to be repurchased | $							$ 556,828
Class B | General Partnership
Units required to be repurchased (in shares)							341
Repurchase price of units (in dollars per unit) | $ / item		996.79				996.79	996.79	996.79
Treasury Units
Repurchase price of depository receipts (in dollars per receipt) | $ / item							54.40
Units required to be repurchased (in shares)							43,095
Repurchase price of units (in dollars per unit) | $ / item							1,632.12
Total cost of repurchase | $							$ 2,344,601