Investment in Unconsolidated Joint Ventures (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Document Period End Date	Mar. 31, 2015
Document Fiscal Year Focus	2015
SUMMARY OF FINANCIAL POSITION:
Total Assets	$ 632,286			$ 619,068
Total Debt	398,966			394,934
Total Equity	206,905			203,085
Company's Investment	78,115				77,461
SUMMARY OF OPERATIONS:
Total Revenues	24,757		25,612
Net Income (Loss)	5,625		4,253
Income (Loss) from Equity Method Investments Gross of Impairment Charges	1,611		1,286
Terminus Office Holdings [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	289,659			288,415
Total Debt	213,047			213,640
Total Equity	63,817			62,830
Company's Investment	32,692				32,323
SUMMARY OF OPERATIONS:
Total Revenues	9,802		9,662
Net Income (Loss)	987		(114)
Income (Loss) from Equity Method Investments Gross of Impairment Charges	369		(79)
EP I LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	84,920			85,228
Total Debt	58,029			58,029
Total Equity	25,306			26,671
Company's Investment	22,376				22,905
SUMMARY OF OPERATIONS:
Total Revenues	3,176		2,952
Net Income (Loss)	735		678
Income (Loss) from Equity Method Investments Gross of Impairment Charges	551		508
EP II LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	53,442			42,772
Total Debt	21,752			12,735
Total Equity	24,939			24,969
Company's Investment	19,806				19,905
SUMMARY OF OPERATIONS:
Net Income (Loss)	30
Income (Loss) from Equity Method Investments Gross of Impairment Charges	(9)
Cousins Watkins LLC [Member]
SUMMARY OF OPERATIONS:
Total Revenues	0		1,276
Net Income (Loss)	0		112
Income (Loss) from Equity Method Investments Gross of Impairment Charges	0		567
Charlotte Gateway Village, LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	129,712			130,272
Total Debt	31,138			35,530
Total Equity	95,583			92,808
Company's Investment	11,218				11,218
SUMMARY OF OPERATIONS:
Total Revenues	8,442		8,363
Net Income (Loss)	3,077		2,811
Income (Loss) from Equity Method Investments Gross of Impairment Charges	303		294
HICO Victory Center LP [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	11,390			10,450
Total Debt				0
Total Equity	11,390			10,450
Company's Investment	8,087			7,572
Temco Associates, LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	6,888			6,910
Total Debt	0			0
Total Equity	6,709			6,709
Company's Investment	3,025				3,027
SUMMARY OF OPERATIONS:
Total Revenues	58		60
Net Income (Loss)	(1)		(18)
Income (Loss) from Equity Method Investments Gross of Impairment Charges	(2)		(5)
CL Realty, L.L.C. [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	7,269			7,264
Total Debt	0			0
Total Equity	7,203			7,042
Company's Investment	3,615				3,546
SUMMARY OF OPERATIONS:
Total Revenues	279		368
Net Income (Loss)	160		229
Income (Loss) from Equity Method Investments Gross of Impairment Charges	69		33
Wildwood Associates
SUMMARY OF FINANCIAL POSITION:
Total Assets	16,426			16,400
Total Debt	0			0
Total Equity	16,359			16,389
Company's Investment	(1,121)	[1]			(1,106)	[1]
SUMMARY OF OPERATIONS:
Total Revenues	0		0
Net Income (Loss)	(30)		(38)
Income (Loss) from Equity Method Investments Gross of Impairment Charges	(15)		(19)
Crawford Long CPI LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	31,184			29,946
Total Debt	75,000			75,000
Total Equity	(45,363)			(45,762)
Company's Investment	(21,585)	[1]			(21,931)	[1]
SUMMARY OF OPERATIONS:
Total Revenues	3,000		2,927
Net Income (Loss)	680		682
Income (Loss) from Equity Method Investments Gross of Impairment Charges	345		374
CF Murfreesboro Associates [Member]
SUMMARY OF OPERATIONS:
Total Revenues	0		0
Net Income (Loss)	0		0
Income (Loss) from Equity Method Investments Gross of Impairment Charges	0		(387)
Other Equity Method Investee [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets	1,396			1,411
Total Debt	0			0
Total Equity	962			979
Company's Investment	2				2
SUMMARY OF OPERATIONS:
Total Revenues	0		4
Net Income (Loss)	(13)		(89)
Income (Loss) from Equity Method Investments Gross of Impairment Charges	$ 0		$ 0

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