SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, policies e - i (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Acquisitions and Disposals [Line Items]
Impairment of long-lived asset	$ 3,500	$ 0	$ 0
Number of properties	211
Impaired Properties [Member]
Significant Acquisitions and Disposals [Line Items]
Number of properties	8
Maximum [Member]
Intangible Assets [Line Items]
Intangible assets amortization period	48 months
Minimum [Member]
Intangible Assets [Line Items]
Intangible assets amortization period	36 months