ACQUISITIONS AND DISPOSITIONS (Narrative) (Details) ft² in Thousands							3 Months Ended								6 Months Ended	10 Months Ended	12 Months Ended
	Sep. 07, 2018 USD ($) ft² a building	Jun. 08, 2018 USD ($) a extention_option	Dec. 28, 2017 USD ($)	Mar. 01, 2017 USD ($)	Jan. 18, 2017 USD ($) a	Jan. 06, 2017 USD ($) a	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) item	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 12, 2017 USD ($)
Number of buildings | building	2
Area of real estate property | ft²	257
Area of land | a	12.9
Payments to acquire real estate	$ 53,000,000
(Loss) gain on disposal of operating assets																	$ (4,000)	$ 3,868,000	$ (1,117,000)
Aggregate principal amount of debt issued																				$ 200,000,000
Equity in earnings from Real Estate and Other Affiliates																	39,954,000	25,498,000	56,818,000
Assets acquired and consolidated into financial statements			$ 43,561,000
Revenues since the acquisition date							$ 464,693,000	$ 257,160,000	$ 181,005,000	$ 161,679,000	$ 300,983,000	$ 258,736,000	$ 308,639,000	$ 231,762,000			1,064,537,000	1,100,120,000	1,035,005,000
Pre-tax net loss since the acquisition date																	$ 73,218,000	120,822,000	$ 320,776,000
Constellation
Ownership interest (as a percent)			50.00%
Portion of refinanced mortgage proceeds used to acquire partner's interest			$ 8,000,000
Liabilities acquired percentage			50.00%
Purchase price of acquisition			$ 16,000,000
Gain recognized from acquisition			17,800,000
Equity in earnings from Real Estate and Other Affiliates																		300,000
Constellation | Construction Loan Payable
Construction loan			$ 15,800,000
Constellation | Constellation Note Payable
Interest rate (as a percent)			4.07%
Aggregate principal amount of debt issued			$ 24,200,000.0
Las Vegas 51s
Ownership interest (as a percent)							50.00%										50.00%
Adjustment to allocate from identified finite-lived intangibles				$ 7,900,000
Landmark Mall
Area of real estate property | a						11.4
Purchase price of acquisition						$ 22,200,000
Las Vegas 51s
Portion of refinanced mortgage proceeds used to acquire partner's interest				16,400,000
Gain recognized from acquisition				$ 5,400,000
Equity in earnings from Real Estate and Other Affiliates																		200,000
Economic/Legal Ownership				50.00%
Contingent liability recorded per the terms of the purchase agreement				$ 400,000
Adjustment to allocate from identified finite-lived intangibles				$ 36,000,000
Acquired intangible assets weighted average amortization period				11 years
Assets acquired and consolidated into financial statements				$ 24,900,000
Liabilities assumed and consolidated into financial statements				$ 3,200,000
Revenues																		1,300,000
Revenues since the acquisition date																$ 6,800,000
Pre-tax net loss since the acquisition date																$ 600,000
Five non-core assets | Disposal by Sale
Number of assets sold | item															5
Proceeds from sale of real estate															$ 52,600,000
(Loss) gain on disposal of operating assets															$ 23,100,000
Corporate gains on sale of properties																		19,200,000
Gain lLoss) on disposition of business																		$ 3,900,000
The Outlet Collection, Elk Grove
Area of land | a					100
Area of land under development | a					64
The Outlet Collection, Elk Grove | Disposal by Sale
Proceeds from sale of real estate					$ 36,000,000
Corporate gains on sale of properties					$ 32,200,000
Area of land sold | a					36
250 Water Street
Area of land purchased | a		1
Purchase price of land acquired		$ 180,000,000
Payments to acquire land		53,100,000
Notes Payable, Other Payables | 250 Water Street
Short-term debt		$ 129,700,000
Interest free term		6 months
Number of extension options | extention_option		3
Extension option, term		6 months
Interest rate (as a percent)		6.00%
Extension option, minimum paydown		$ 30,000,000.0