STORAGE FACILITIES (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
STORAGE FACILITIES
Total	$ 2,432,415,000		$ 2,107,469,000
Less: Accumulated depreciation	(340,365,000)		(318,749,000)
Storage facilities, net	2,092,050,000		1,788,720,000
STORAGE FACILITIES, other disclosures
Fully depreciated assets removed from storage facilities and accumulated depreciation	24,800,000	41,200,000
Land
STORAGE FACILITIES
Total	461,816,000		417,067,000
Buildings and improvements
STORAGE FACILITIES
Total	1,824,107,000		1,574,769,000
Equipment
STORAGE FACILITIES
Total	141,097,000		110,371,000
Construction in progress
STORAGE FACILITIES
Total	$ 5,395,000		$ 5,262,000