Investment in Unconsolidated Joint Ventures (Details Textual) (USD $)	11 Months Ended	12 Months Ended							12 Months Ended					12 Months Ended										12 Months Ended					12 Months Ended									12 Months Ended		12 Months Ended						12 Months Ended														12 Months Ended				12 Months Ended											12 Months Ended				1 Months Ended	12 Months Ended	1 Months Ended
	Nov. 30, 2011 sqft	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2006 CP Venture IV Holdings LLC [Member]	Dec. 31, 2011 CP Venture IV Holdings LLC [Member]	Dec. 31, 2010 CP Venture IV Holdings LLC [Member]	Jun. 30, 2006 CP Venture IV Holdings LLC [Member]	Dec. 31, 2011 CP Venture Five LLC [Member] sqft Property	Dec. 31, 2010 CP Venture Five LLC [Member] Secured Mortgage Note Payable [Member]	Sep. 30, 2010 CP Venture Five LLC [Member] Secured Mortgage Note Payable [Member]	Dec. 31, 2011 CP Venture Five LLC [Member] Suburban Atlanta, Georgia [Member] Property	Dec. 31, 2011 CP Venture Five LLC [Member] Viera, Florida [Member] Property	Dec. 31, 2011 Charlotte Gateway Village, LLC [Member] sqft	Dec. 31, 2011 Charlotte Gateway Village, LLC [Member] Secured Mortgage Note Payable [Member]	Dec. 31, 2011 CF Murfreesboro Associates [Member] sqft	Dec. 31, 2011 Palisades West LLC [Member]	Dec. 31, 2011 Palisades West LLC [Member] Dimensional Fund Advisors [Member]	Dec. 31, 2011 Palisades West LLC [Member] Dimensional Fund Advisors [Member] One Building [Member]	Dec. 31, 2011 Palisades West LLC [Member] Forestar [Member] Two Building [Member]	Dec. 31, 2011 Palisades West LLC [Member] Cousins [Member] Two Building [Member]	Dec. 31, 2011 Palisades West LLC [Member] Third Party [Member] Two Building [Member]	Dec. 31, 2011 Palisades West LLC [Member] Real Estate Group [Member]	Dec. 31, 2011 Palisades West LLC [Member] TEXAS sqft	Dec. 31, 2011 Palisades West LLC [Member] TEXAS One Building [Member] sqft	Dec. 31, 2011 Palisades West LLC [Member] TEXAS Two Building [Member] sqft	Dec. 31, 2011 Palisades West LLC [Member] TEXAS Building [Member] Property	Dec. 31, 2011 CP Venture LLC entities [Member]	Dec. 31, 2011 CP Venture LLC entities [Member] Office Building [Member] sqft Property	Dec. 31, 2011 CP Venture LLC entities [Member] Retail [Member] sqft Property	Dec. 31, 2011 MSREF/Cousins Terminus 200 LLC [Member] sqft	Dec. 31, 2011 Terminus 200 LLC [Member]	Dec. 31, 2010 Terminus 200 LLC [Member]	Dec. 31, 2011 CL Realty, L.L.C. [Member] acre Lots	Dec. 31, 2010 CL Realty, L.L.C. [Member] acre Lots	Dec. 31, 2009 CL Realty, L.L.C. [Member] Lots acre	Dec. 31, 2011 CL Realty, L.L.C. [Member] Land [Member] acre	Dec. 31, 2011 CL Realty, L.L.C. [Member] Residential Real Estate [Member] Project	Dec. 31, 2011 CL Realty, L.L.C. [Member] Forestar [Member]	Dec. 31, 2011 CL Realty, L.L.C. [Member] GEORGIA Residential Real Estate [Member] Project	Dec. 31, 2011 CL Realty, L.L.C. [Member] TEXAS Residential Real Estate [Member] Project	Dec. 31, 2011 CL Realty, L.L.C. [Member] FLORIDA Residential Real Estate [Member] Project	Dec. 31, 2011 Ten Peachtree Place Associates [Member]	Dec. 31, 2010 Ten Peachtree Place Associates [Member]	Dec. 31, 2011 Ten Peachtree Place Associates [Member] Wholly-owned subsidiary of The Coca-Cola Company [Member]	Dec. 31, 2011 Ten Peachtree Place Associates [Member] Secured Mortgage Note Payable [Member]	Dec. 31, 2011 Ten Peachtree Place Associates [Member] Midtown Atlanta, Georgia [Member] acre	Dec. 31, 2011 Temco Associates, LLC [Member] acre	Dec. 31, 2010 Temco Associates, LLC [Member] acre	Dec. 31, 2009 Temco Associates, LLC [Member] acre	Dec. 31, 2011 Temco Associates, LLC [Member] Residential Real Estate [Member] Lots	Dec. 31, 2010 Temco Associates, LLC [Member] Residential Real Estate [Member] Lots	Dec. 31, 2009 Temco Associates, LLC [Member] Residential Real Estate [Member] Lots	Dec. 31, 2011 Temco Associates, LLC [Member] Forestar [Member]	Dec. 31, 2010 Temco Associates, LLC [Member] GEORGIA Residential Real Estate [Member] Lots Property	Dec. 31, 2011 Crawford Long - CPI, LLC [Member]	Dec. 31, 2010 Crawford Long - CPI, LLC [Member]	Dec. 31, 2011 Crawford Long - CPI, LLC [Member] Emory University [Member]	Dec. 31, 2011 Crawford Long - CPI, LLC [Member] Secured Mortgage Note Payable [Member]	Dec. 31, 2011 Crawford Long - CPI, LLC [Member] Midtown Atlanta, Georgia [Member] sqft	Dec. 31, 2011 Wildwood Associates [Member]	Dec. 31, 2011 Wildwood Associates [Member] IBM [Member]	Dec. 31, 2011 Wildwood Associates [Member] Suburban Atlanta, Georgia [Member] acre	Dec. 31, 2011 Cousins Watkins LLC [Member]	Dec. 31, 2010 Cousins Watkins LLC [Member] MortgagePool	Dec. 31, 2010 Cousins Watkins LLC [Member] Maximum [Member]	Dec. 31, 2010 Cousins Watkins LLC [Member] Minimum [Member]	Dec. 31, 2010 Cousins Watkins LLC [Member] Retail [Member] Property	Dec. 31, 2010 Cousins Watkins LLC [Member] Mortgages [Member]	Dec. 31, 2011 Cousins Watkins LLC [Member] Four Loans [Member]	Dec. 31, 2011 TRG Columbus Development Venture, Ltd. [Member] Unit Project	Dec. 31, 2010 TRG Columbus Development Venture, Ltd. [Member]	Dec. 31, 2011 TRG Columbus Development Venture, Ltd. [Member] 50 Biscayne Ventures, LLC [Member]	Dec. 31, 2011 TRG Columbus Development Venture, Ltd. [Member] Related Group of Florida [Member]	Dec. 31, 2011 Pine Mountain Builders, LLC [Member] Property	Dec. 31, 2010 Pine Mountain Builders, LLC [Member] Property	Dec. 31, 2009 Pine Mountain Builders, LLC [Member] Property	Dec. 31, 2011 Pine Mountain Builders, LLC [Member] Fortress Construction Company [Member]	Jun. 28, 2011 EP I LLC [Member]	Dec. 31, 2011 EP I LLC [Member]	Jun. 28, 2011 EP I LLC [Member] Gables Realty Limited [Member]	Dec. 31, 2011 EP I LLC [Member] Gables Realty Limited [Member]
Investment In Unconsolidated Joint Ventures (Textual) [Abstract]
Date of joint venture formation					Jun. 01, 2006
Maximum amount available under construction facility, revised																$ 113,200,000																																																																$ 61,100,000
Construction loan secured by a project totaling																																		1,100,000
Investment by third party in joint venture																																							50.00%
Square footage of real estate property	775,000								1,200,000					1,100,000		751,000								373,000	216,000	157,000			69,000	934,000	566,000																260,000													358,000
No. of residential project																																						14		1	10	3
Number of lots in real estate property sold																																		445	330	128
Acres of land to be developed or sold as undeveloped tracts																																					1,124											5,800
Acres of land available for development or sale																																																															36
Company's ownership percentage in equity method investment								11.50%									50.00%											10.40%			20.00%			50.00%									50.00%					50.00%								50.00%					50.00%												88.25%		50.00%					75.00%		25.00%
Debt secured by a golf course																																																2,800,000
Original principal of mortgage note payable of Joint Venture											36,600,000
Outstanding amount of mortgage note payable of joint venture						36,000,000									83,100,000																															26,200,000													47,600,000
Cash balance of equity method investee							2,200,000							1,600,000		6,700,000	1,200,000											1,800,000						797,000										753,000													2,300,000							513,000								722,000
Interest rate on mortgage loan											4.52%				6.41%																															5.39%													5.90%
Amortization period for mortgage note payable of Joint Venture											30 years
Remaining lots to be developed and/or sold																																		3,141																					1,513
Acres of land sold																																		20	657	4												19	0	42
Payments of guarantees under debt agreements			17,250,000																														17,250,000
Debt instrument description of variable rate basis, LIBOR		the spread over LIBOR was 2.0%																														LIBOR																																		LIBOR	LIBOR
Adjusted interest rate for construction loan																LIBOR
Spread over LIBOR		2.00%														3.00%																2.25%																																		2.85%	2.65%
Percentage of building leased to partners																			100.00%	21.00%	3.00%	73.00%
Maturity date of debt instrument										Dec. 01, 2017					Dec. 01, 2016	Jul. 20, 2010																		Nov. 01, 2012												Apr. 01, 2015		May 12, 2012
Date instrument, payment date																																		Jan. 01, 2012
Shares impairment charges																																		13,600,000	2,200,000	2,600,000												14,600,000		631,000
Percentage of real estate property leased														100.00%
Number of real estate properties owned by equity investee									5			3	2														2		1	3																									4													4
Mortgage loans on real estate maximum borrowing capacity																																																																33,500,000
Ending year of lease agreement														2016
Basis of allocation of joint ventures net income or loss and cash distributions														First to the Company so that it receives a cumulative compounded return equal to 11.46% on its capital contributions, second to BOA until it receives an amount equal to the aggregate amount distributed to the Company and then 50% to each member
Maximum IRR on project														17.00%
Ownership Percentage of partner joint venture																50.00%																													50.00%									50.00%				50.00%				50.00%												60.00%				50.00%
Partner's ownership percentage in equity method investment																																																																									40.00%
Maximum amount available under construction facility, previous																131,000,000
Period for conditioned extension option under construction loan																1 year
Extended maturity date of construction loan																Jul. 20, 2013																Dec. 13, 2013
Decreased amount available under construction loan																																92,000,000
Principal payments made in conjunction with loan modification																8,200,000
Fees paid by Venture for modifications in terms of Construction loan																1,000,000
Amount drawn on construction loan																98,900,000
Guarantee of indebtedness																26,200,000
Number of lots sold by Temco																																																			11	2	0
Company's share of impairment of equity investee																																																																												1,500,000
Interest rate on additional capital contributions made by partners																																											8.00%
Next cash flows after august 1, 2011																																											15,300,000
Percentage of cash flow distributed to company																																											15.00%
Percentage of cash flow distributed to partners																																											85.00%
Percentage of cash flow each partner is entitled to receive																																											50.00%
Approximate cash contribution of Company in joint venture																																																																	14,900,000														8,100,000		3,800,000
Additional cash contributions to be made to joint venture for EPI																																																																																6,500,000
Number of mortgage loans obtained by joint venture																																																																	4
Outstanding balance of mortgage loan																																																																						28,600,000
Maturity date of mortgage loans																																																																Jan. 01, 2016																Jun. 28, 2014
Extension of mortgage loans maturity, conditions																																																																two one-year terms, provided certain conditions are met																two one-year terms, provided certain conditions are met
Percentage of loans guaranteed by Company																																																																	25.00%
Approximate amount of loans guaranteed by Company																																																																					4,100,000											11,500,000		3,800,000
Fair value of guarantees																																																																	40,750
Internal rate of return on project																																																																16.00%
Income recognized by Biscayne																																																																									40.00%
Multi family residential units financed by joint venture																																																																							5
Percentage of ownership																		25.00%					25.00%																																																		11.75%
Number of Homes Sold																																																																											8	14	4
Interest rate on loan																LIBOR plus 1.15%																																LIBOR plus 6.5%
Company's Investment		160,587,000	167,108,000																																																										1,600,000
Expected investment balance after sale of joint venture assets																																		3,400,000														2,900,000
Fees earned from unconsolidated joint ventures		10,100,000	10,400,000	8,900,000
Number of units in real estate property																																																																							529
Debt instrument, basis spread on variable rate maximum																																																																	we
Transfer from predevelopment assets to investment in joint venture related to the EP I, LLC project		$ 6,200,000																																																																													$ 6,200,000