TREASURY UNITS (Details)				1 Months Ended	3 Months Ended	6 Months Ended		120 Months Ended	130 Months Ended
	Mar. 10, 2015 shares	Aug. 31, 2007 $ / item shares	Aug. 20, 2007 shares	Sep. 30, 2007 $ / item shares	Dec. 31, 2007 $ / item shares	Jun. 30, 2018 $ / item shares	Jun. 30, 2017 USD ($) shares	Dec. 31, 2017 $ / item shares	Jun. 30, 2018 USD ($) $ / item shares	Mar. 06, 2008 shares
Treasury units						55,839			55,839
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		1,365,306		1,365,306	1,365,306	1,365,306		1,365,306
Repurchase price of depository receipts (in dollars per receipt) | $ / item									27.14
Units repurchased (in shares)							23
Total cost of repurchase | $							$ 42,548		$ 40,274,000
General Partnership
Treasury units						559			559
Fixed distribution percentage of unit holders						1.00%
Number of depository receipts repurchased		162		162	162	162		162
Total cost of repurchase | $							$ 426
Treasury Units
Units repurchased (in shares)							23
Class A
Treasury units						44,671			44,671
Fixed distribution percentage of unit holders						80.00%
Repurchase price of units (in dollars per unit) | $ / item		814.20		814.20	814.20	814.20		814.20
Total cost of repurchase | $							$ 34,038
Class B
Treasury units						10,609			10,609
Fixed distribution percentage of unit holders						19.00%
Number of depository receipts repurchased		3,072		3,072	3,072	3,072		3,072
Total cost of repurchase | $							$ 8,084
Class B | General Partnership
Repurchase price of units (in dollars per unit) | $ / item		926.26		926.26	926.26	926.26		926.26