ACQUISITIONS AND DISPOSITIONS (Details) (USD $)	1 Months Ended					0 Months Ended	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended
	Aug. 31, 2012	May 31, 2012 Millennium Woodlands Phase II, LLC. item	Aug. 31, 2012 70 Columbia Corporate Center sqft	Dec. 31, 2012 70 Columbia Corporate Center	Aug. 15, 2012 70 Columbia Corporate Center sqft	Jul. 02, 2011 The Woodlands item sqft acre	Jul. 31, 2011 The Woodlands	Jun. 30, 2011 The Woodlands	Dec. 31, 2011 The Woodlands	Dec. 31, 2012 The Woodlands	Dec. 31, 2011 The Woodlands	Dec. 31, 2010 The Woodlands	May 31, 2012 Millennium Waterway Apartments item	Dec. 31, 2012 Millennium Waterway Apartments
Acquisitions
Area of real estate property acquired (in square foot)					169,590
Purchase price					$ 17,500,000	$ 117,500,000
Interest rate (as a percent)				4.25%									3.75%
Percentage of appreciation in the market value of building			30.00%
Percentage of building leased at closing					23.70%
Area of building leased			76,308
Percentage of occupancy after lease is executed					68.70%
Amount deposited in escrow account			5,000,000
Percentage of cumulative preferred return after debt service on amount invested in property			10.00%
Original contributed equity					5,000,000
Percentage distribution of excess proceeds after repayment of outstanding debt and preferred return	70.00%		30.00%
Total assets consolidated into financial statements at fair value as of the acquisition date						587,558,000							78,600,000
Total liabilities consolidated into financial statements at fair value as of the acquisition date						338,600,000							56,400,000
Portion of refinanced mortgage proceeds used to acquire partner's interest						20,000,000							6,900,000
Non-recourse mortgage assumed													55,600,000
Term of debt instrument													10 years
Ownership interest (as a percent)													100.00%
Number of units in Class A multi-family unit in The Woodlands Town Center to be constructed		314
Percentage of economic interest acquired						47.50%
Percentage of legal interest acquired						57.50%
Existing economic interest (as a percent)								52.50%
Net book value of existing economic interest								134,800,000
Area of unsold residential land acquired (in acres)						1,324
Lots of unsold residential land acquired						4,395
Area of unsold commercial land acquired (in acres)						962
Number of Units Acquired in Real Estate Property						865							393
Number of room resorts and conference centre						440
Number of holes on the golf and country club aquired						36
Area of office space acquired (in square feet)						434,328
Area of retail and service space acquired (in square feet)						203,282
Acquisition price represented by a non-interest bearing promissory note						97,500,000
Estimated useful life							40 years
Assets acquired consolidated						587,558,000							78,600,000
Liabilities acquired consolidated						338,600,000							56,400,000
After-tax loss on the remeasurement relating to existing economic interest								3,900,000
Amounts recorded for the assets acquired and liabilities assumed at the acquisition date
Master Planned Community Assets						267,251,000
Land						44,597,000
Buildings and Equipment						116,061,000
Investments in Real Estate Affiliates						36,764,000
Cash						25,492,000
Accounts receivable						7,548,000
Notes receivable						3,189,000
Municipal Utility District receivables						61,700,000
Other assets						24,956,000
Total assets						587,558,000							78,600,000
Mortgages, notes and loans payable						(296,695,000)
Accounts payable and accrued expenses						(41,900,000)
Noncontrolling interests						(3,700,000)
Total liabilities and noncontrolling interests						(342,295,000)
Total identifiable net assets						245,263,000
Revenues and net losses included in the condensed consolidated statement of operations since the acquisition date
Revenues									84,600,000					4,400,000
Net income (loss)									500,000					(1,300,000)
Impact of increase in cost of sales on net loss											6,100,000
Pro Forma Information
Total revenues											357,472,000	294,310,000
Net income (loss) attributable to common shareholders											$ 157,520,000	$ (52,081,000)
Effective tax rate (as a percent)										36.00%