PARTNERS' CAPITAL (Details)		1 Months Ended				6 Months Ended
	Jan. 03, 2012	Jul. 31, 2018 $ / item	Apr. 30, 2018 $ / item	Jan. 31, 2018 $ / item	Dec. 31, 2017 $ / item	Jun. 30, 2018 item $ / item	Jun. 30, 2017 $ / item	Sep. 30, 2017 $ / item	Mar. 31, 2017 $ / item	Aug. 20, 2007
Depositary receipts exchange ratio for Class A units | item						30
Quarterly distributions per depositary receipt (in dollars per receipt)					(0.30)		(0.30)	(0.30)	(0.30)
Quarterly distribution per unit (in dollars per unit)					9.00		9.00	9.00	9.00
Special distribution per unit (in dollars per unit)					28.50
Special distribution per depository receipt (in dollars per receipt)					0.95
Earnings per depository receipt
Net Income per Depositary Receipt (in dollars per receipt)						0.52	1.17
Distributions per Depositary Receipt (in dollars per share)						0.60	0.60
Limited Partner
Number of classes of partners | item						2
General Partnership
Number of classes of partners | item						1
Fixed distribution percentage of unit holders						1.00%
Class A
Fixed distribution percentage of unit holders						80.00%
Forward split of depositary receipts	3
Exchange ratio of depositary receipts for partnership units before adjustment	10
Exchange ratio of depositary receipts for partnership units after adjustment	30
Number of units in each depository receipt	0.03333									0.1
Quarterly distribution per unit approved (in dollars per unit)			9.00	9.00
Quarterly distributions per depositary receipt (in dollars per receipt)			(0.30)	0.30
Class A | Subsequent event
Quarterly distribution per unit approved (in dollars per unit)		9.00
Quarterly distributions per depositary receipt (in dollars per receipt)		(0.30)
Class B
Fixed distribution percentage of unit holders						19.00%