OTHER ASSETS AND LIABILITIES (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Prepaid Expenses and Other Assets
Straight-line rent	$ 42,188,000		$ 39,136,000
Security and escrow deposits	16,888,000		16,949,000
Equipment, net of accumulated depreciation of $7.1 million and $6.9 million, respectively	16,798,000		16,955,000
Prepaid expenses	12,247,000		11,731,000
Other	11,873,000		19,242,000
Interest rate swap derivative assets	9,011,000		4,470,000
Tenant incentives and other receivables	8,208,000		8,482,000
Federal income tax receivable	2,198,000		2,198,000
Condominium deposits	218,000		0
Condominium receivables	0		158,516,000
Total prepaid expenses and other assets	210,327,000		370,027,000
Accumulated depreciation on other equipment	7,100,000		6,900,000
Decrease in prepaid expenses and other assets	159,700,000
Decrease in condominium receivables	158,500,000
Decrease in other assets	7,400,000
Decrease in in-place leases	1,000,000
Increase in derivative assets	4,500,000
Increase in straight line rent	3,100,000
Increase in prepaid expense	500,000
Accounts Payable and Accrued Liabilities [Abstract]
Construction payables	244,192,000		217,838,000
Condominium deposit liabilities	196,337,000		55,975,000
Deferred income	52,758,000		53,337,000
Other	27,552,000		34,699,000
Accounts payable and accrued expenses	26,328,000		35,887,000
Tenant and other deposits	19,681,000		18,937,000
Accrued payroll and other employee liabilities	18,246,000		41,236,000
Straight-line ground rent liability	15,399,000		14,944,000
Accrued real estate taxes	11,271,000		22,289,000
Accrued interest	7,507,000		20,322,000
Interest rate swaps	0		5,961,000
Above-market ground leases	0		293,000
Accounts payable and accrued expenses	619,271,000		521,718,000
Increase in accounts payable and accrued expenses	97,600,000
Increase in condominium deposits liability	140,400,000
Increase in construction payables	26,400,000
Other increases	1,200,000
Decrease in accrued payroll and other employee liabilities	23,000,000
Decrease in accrued interest	12,800,000
Decrease in accrued real estate taxes	11,000,000
Decrease in accounts payable and accrued expenses	9,600,000
Decrease in other	7,100,000
Decrease in interest rate swap liability	6,000,000
Decreases in other	$ 900,000
Senior Notes 6.875 Percent Due 2021
Accounts Payable and Accrued Liabilities [Abstract]
Interest rate (as a percent)	6.875%
Leases, Acquired-in-Place
Prepaid Expenses and Other Assets
Intangibles	$ 34,465,000		34,802,000
Net carrying amount	9,805,000		10,821,000
Ground Leases below Market
Prepaid Expenses and Other Assets
Special Improvement District receivable	26,371,000		26,430,000
Net carrying amount	18,562,000		18,647,000
Ground Leases above Market
Prepaid Expenses and Other Assets
Net carrying amount	1,495,000		$ 1,648,000
Unsecured 5.375% Senior Notes | 5.375% Senior Note Due 2025
Accounts Payable and Accrued Liabilities [Abstract]
Loan amount	$ 1,000,000,000
Interest rate (as a percent)	5.375%
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Prepaid Expenses and Other Assets
Condominium receivables	$ 154,200,000	$ (154,200,000)
Total prepaid expenses and other assets	(277,404,000)	5,600,000
Accounts Payable and Accrued Liabilities [Abstract]
Accounts payable and accrued expenses	$ 107,948,000	$ 95,000,000