INTANGIBLES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Intangible assets:
Accumulated amortization	$ (382,004)	$ (352,692)
Goodwill	457,598	490,452
Net intangible assets	1,092,719	1,152,842
Remaining weighted average amortization period	19 years 7 months 6 days	19 years 3 months 18 days
Intangible liabilities:
Accumulated amortization	(88,442)	(78,560)
Purchase option intangibles	36,048	36,048
Net intangible liabilities	405,779	416,361
Remaining weighted average amortization period	15 years 2 months 12 days	15 years 3 months 18 days
Above market lease intangibles
Intangible assets:
Intangibles	214,863	215,367
Remaining weighted average amortization period	9 years 4 months 24 days	9 years 6 months
In-place and other lease intangibles
Intangible assets:
Intangibles	769,159	766,337
Remaining weighted average amortization period	23 years 9 months 18 days	23 years 3 months 18 days
Other intangibles
Intangible assets:
Intangibles	33,103	33,378
Remaining weighted average amortization period	8 years 7 months 6 days	8 years 7 months 6 days
Below market lease intangibles
Intangible liabilities:
Lease intangibles	429,633	429,907
Remaining weighted average amortization period	15 years 2 months 12 days	15 years 3 months 18 days
Other lease intangibles
Intangible liabilities:
Lease intangibles	$ 28,540	$ 28,966
Remaining weighted average amortization period	15 years 9 months 18 days	15 years 9 months 18 days