NET INCOME PER UNIT (Tables)

12 Months Ended

Dec. 31, 2012

NET INCOME PER UNIT [Abstract]

Unit amounts used in the computation of basic and diluted net income per unit

	Year Ended December 31,
	2012	2011	2010
Basic units outstanding:
Weighted-average number of basic units outstanding	42,576,858	42,546,096	42,517,525
Diluted units outstanding:
Weighted-average number of basic units outstanding	42,576,858	42,546,096	42,517,525
Effect of dilutive securities	7,809	26,521	8,662
Weighted-average number of diluted units outstanding	42,584,667	42,572,617	42,526,187