Investment in Unconsolidated Joint Ventures (Details) (USD $)	9 Months Ended				3 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended			9 Months Ended						3 Months Ended	9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended			3 Months Ended	9 Months Ended			9 Months Ended					3 Months Ended	9 Months Ended					9 Months Ended						9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Oct. 09, 2013 EP II LLC [Member] Subsequent Event [Member] sqft	Sep. 30, 2013 CP Venture Two LLC [Member]	Sep. 30, 2013 CP Venture Two LLC [Member]	Sep. 30, 2012 CP Venture Two LLC [Member]	Dec. 31, 2012 CP Venture Two LLC [Member]	Sep. 30, 2013 Cp Venture Five LLC [Member]	Sep. 30, 2013 Cp Venture Five LLC [Member]	Sep. 30, 2012 Cp Venture Five LLC [Member]	Dec. 31, 2012 Cp Venture Five LLC [Member]	Sep. 30, 2013 MSREF Terminus Two Hundred LLC [Member]		Sep. 30, 2012 MSREF Terminus Two Hundred LLC [Member]		Dec. 31, 2012 MSREF Terminus Two Hundred LLC [Member]		Sep. 30, 2013 CP Venture Two LLC and CP Venture Five LLC [Domain]	Sep. 30, 2013 EP I LLC [Member]	Sep. 30, 2012 EP I LLC [Member]	Dec. 31, 2012 EP I LLC [Member]	Sep. 30, 2013 Cousins Watkins LLC [Member]	Sep. 30, 2012 Cousins Watkins LLC [Member]	Dec. 31, 2012 Cousins Watkins LLC [Member]	Sep. 30, 2013 Charlotte Gateway Village, LLC [Member]	Sep. 30, 2012 Charlotte Gateway Village, LLC [Member]	Dec. 31, 2012 Charlotte Gateway Village, LLC [Member]	Sep. 30, 2013 Temco Associates, LLC [Member]	Sep. 30, 2012 Temco Associates, LLC [Member]	Dec. 31, 2012 Temco Associates, LLC [Member]	Sep. 30, 2013 CL Realty, L.L.C. [Member]	Sep. 30, 2012 CL Realty, L.L.C. [Member]	Dec. 31, 2012 CL Realty, L.L.C. [Member]	Sep. 30, 2013 CF Murfreesboro Associates [Member]	Sep. 30, 2013 CF Murfreesboro Associates [Member]	Sep. 30, 2012 CF Murfreesboro Associates [Member]	Dec. 31, 2012 CF Murfreesboro Associates [Member]	Sep. 30, 2013 Wildwood Associates		Sep. 30, 2012 Wildwood Associates	Dec. 31, 2012 Wildwood Associates		Jun. 30, 2013 Crawford Long CPI LLC [Member]	Sep. 30, 2013 Crawford Long CPI LLC [Member]		Sep. 30, 2012 Crawford Long CPI LLC [Member]	Dec. 31, 2012 Crawford Long CPI LLC [Member]		Sep. 30, 2013 Terminus Office Holdings [Member]		Sep. 30, 2012 Terminus Office Holdings [Member]		Dec. 31, 2012 Terminus Office Holdings [Member]		Sep. 30, 2013 Palisades West LLC [Member]	Sep. 30, 2012 Palisades West LLC [Member]	Sep. 30, 2013 Ten Peachtree Place Associates [Member]	Sep. 30, 2012 Ten Peachtree Place Associates [Member]	Sep. 30, 2013 Other Equity Method Investee [Member]	Sep. 30, 2012 Other Equity Method Investee [Member]	Dec. 31, 2012 Other Equity Method Investee [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds from Divestiture of Interest in Joint Venture					$ 23,300,000				$ 30,000,000
Gain on Sale of Investments																			37,000,000
Distributions from Unconsolidated Joint Ventures	86,752,000	25,767,000																																	33,800,000
Gain on Sale of Depreciated Investment Properties																																			23,500,000
Debt Instrument, Face Amount																																												75,000,000
SUMMARY OF FINANCIAL POSITION:
Total Assets	653,828,000		950,013,000		0	0		96,345,000	0	0		286,647,000	0	[1]			95,520,000	[1]		88,382,000		83,235,000	53,211,000		54,285,000	138,852,000		140,384,000	8,576,000		8,409,000	7,353,000		7,549,000	0	0		121,451,000	21,096,000			21,176,000			33,762,000			32,818,000		300,683,000	[1]			0	[1]					1,913,000		2,194,000
Total Debt	432,124,000		390,794,000		0	0		0	0	0		35,417,000	0	[1]			74,340,000	[1]		56,313,000		43,515,000	27,852,000		28,244,000	56,462,000		68,242,000	0		0	0		0	0	0		94,540,000	0			0			75,000,000			46,496,000		216,497,000	[1]			0	[1]					0		0
Total Equity	200,135,000		535,515,000		0	0		94,819,000	0	0		243,563,000	0	[1]			19,659,000	[1]		30,249,000		32,611,000	23,857,000		25,259,000	79,913,000		70,917,000	8,267,000		8,233,000	7,147,000		7,155,000	0	0		25,411,000	21,096,000			21,173,000			(42,080,000)			(15,129,000)		70,056,000	[1]			0	[1]					1,630,000		1,844,000
Company's Investment	76,497,000		89,797,000		0	0		2,894,000	0	0		13,884,000	0	[1]			3,930,000	[1]		26,079,000		27,864,000	17,209,000		16,692,000	11,260,000		10,299,000	4,083,000		4,095,000	3,571,000		3,579,000	0	0		14,571,000	(1,727,000)	[2]		(1,664,000)	[2]		(19,959,000)	[2]		(6,407,000)	[2]	35,923,000	[1]			0	[1]					58,000		60,000
SUMMARY OF OPERATIONS:
Total Revenues	113,003,000	113,621,000				12,965,000	14,535,000			20,192,000	22,558,000		1,268,000	[1]	9,242,000	[1]				5,499,000	306,000		4,297,000	4,365,000		25,079,000	24,821,000		437,000	560,000		1,246,000	2,294,000			8,079,000	9,920,000		0		0				8,826,000		8,697,000			23,842,000	[1]	0	[1]			0	12,566,000	0	2,488,000	1,273,000	1,269,000
Net Income (Loss)	68,750,000	44,490,000				7,035,000	7,280,000			3,056,000	2,814,000		(172,000)	[1]	(727,000)	[1]				(348,000)	(53,000)		16,000	24,000		7,931,000	7,189,000		48,000	(141,000)		801,000	840,000			48,969,000	316,000		(126,000)		(127,000)				2,134,000		1,908,000			(219,000)	[1]	0	[1]			(27,000)	4,350,000	0	20,938,000	(348,000)	(121,000)
Income (Loss) from Equity Method Investments Gross of Impairment Charges	65,862,000	14,217,000				21,592,000	752,000			17,146,000	778,000		(28,000)	[1]	(146,000)	[1]				(261,000)	(39,000)		1,738,000	1,810,000		882,000	882,000		(12,000)	(275,000)		392,000	105,000			23,562,000	(46,000)		(63,000)		(63,000)				1,028,000		950,000			(110,000)	[1]	0	[1]			0	2,083,000	0	7,852,000	(4,000)	(426,000)
Debt Instrument, Interest Rate, Stated Percentage																																												3.50%
Proceeds from Issuance of Long-term Debt																																												14,300,000
Number of Apartment Units				307
Area of Real Estate Property				0
Projected cost				$ 73,300,000

[1] See note 7 for further discussion of the transactions affecting these entities.

[2] Negative balances are included in deferred income on the balance sheets.