REAL ESTATE ACTIVITIES Real Estate Activities (Acquisition) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Deferred costs and other assets, net		$ 81,574	$ 87,017
Springfield Town Center [Member]
Business Acquisition [Line Items]
Liabilities related to future tenant improvements	$ 14,800
Land	119,912
Land Improvements	35,565
Buildings and Improvements, Gross	299,012
Improvements, Common Area	16,776
Finite-Lived Intangible Asset, Acquired-in-Place Leases	18,123
Above Market Lease Gross	260
Below Market Lease, Gross	(393)
Ground Leases, Gross	(5,882)
Deferred costs and other assets, net	3,231
Business Combination, Consideration Transferred	486,600
Assumption and payoff of long term debt	263,800
Present value of additional consideration	$ 8,600