Investment in Unconsolidated Joint Ventures (Summary of Financial Data and Principal Activities) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Fees Earned from Unconsolidated Joint Ventures		$ 6,000	$ 5,400	$ 8,000
Document Fiscal Year Focus		2015	2014	2013
SUMMARY OF FINANCIAL POSITION:
Total Assets		$ 644,880	$ 619,068
Total Debt		401,977	394,934
Total Equity		219,079	203,085
Company's Investment		79,434	77,461
SUMMARY OF OPERATIONS:
Total Revenues		110,689	109,326	$ 137,107
Net Income (Loss)		23,711	25,357	72,894
Company's Share of Income (Loss)		8,302	11,268	67,325
Terminus Office Holdings [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		277,444	288,415
Total Debt		211,216	213,640
Total Equity		56,369	62,830
Company's Investment		29,110	32,323
SUMMARY OF OPERATIONS:
Total Revenues		40,250	39,531	33,109
Net Income (Loss)		2,789	663	(408)
Company's Share of Income (Loss)		1,395	308	(182)
EP I LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		83,115	85,228
Total Debt		58,029	58,029
Total Equity		24,172	26,671
Company's Investment		21,502	22,905
SUMMARY OF OPERATIONS:
Total Revenues		12,558	12,049	8,261
Net Income (Loss)		3,177	2,583	100
Company's Share of Income (Loss)		2,197	1,937	75
Charlotte Gateway Village, LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		123,531	130,272
Total Debt		17,536	35,530
Total Equity		104,336	92,808
Company's Investment		11,190	11,218
SUMMARY OF OPERATIONS:
Total Revenues		33,724	33,903	33,281
Net Income (Loss)		12,737	11,645	10,693
Company's Share of Income (Loss)		1,183	1,176	1,176
HICO Victory Center LP [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		13,532	10,450
Total Debt			0
Total Equity		13,229	10,450
Company's Investment		9,138	7,572
SUMMARY OF OPERATIONS:
Total Revenues		262	0	0
Net Income (Loss)		204	0	0
Company's Share of Income (Loss)		102	0	0
Carolina Square Holdings LP [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		15,729	0
Total Debt			0
Total Equity		12,085	0
Company's Investment		6,782	0
EP II LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		70,704	42,772
Total Debt		40,910	12,735
Total Equity		24,331	24,969
Company's Investment		19,118	19,905
SUMMARY OF OPERATIONS:
Total Revenues		1,264	0	0
Net Income (Loss)		(638)	0	0
Company's Share of Income (Loss)		(466)	0	0
Temco Associates
SUMMARY OF FINANCIAL POSITION:
Total Assets		5,284	6,910
Total Debt		0	0
Total Equity		5,133	6,709
Company's Investment		977	3,027
SUMMARY OF OPERATIONS:
Total Revenues		9,485	2,155	630
Net Income (Loss)		2,358	495	96
Company's Share of Income (Loss)		2,351	(6)	(12)
CL Realty, L.L.C. [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		7,872	7,264
Total Debt		0	0
Total Equity		7,662	7,042
Company's Investment		3,515	3,546
SUMMARY OF OPERATIONS:
Total Revenues		855	1,573	1,603
Net Income (Loss)		424	1,069	1,027
Company's Share of Income (Loss)		220	542	524
HICO Avalon LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		2,107	0
Total Debt			0
Total Equity		1,646	0
Company's Investment		1,245	0
SUMMARY OF OPERATIONS:
Total Revenues		0	0	0
Net Income (Loss)		(40)	0	0
Company's Share of Income (Loss)		(23)	0	0
Wildwood Associates [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		16,419	16,400
Total Debt		0	0
Total Equity		16,354	16,389
Company's Investment	[1]	(1,122)	(1,106)
SUMMARY OF OPERATIONS:
Total Revenues		0	3,329	0
Net Income (Loss)		(120)	(1,704)	(151)
Company's Share of Income (Loss)		(59)	2,097	(75)
Crawford Long CPI LLC [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		29,143	29,946
Total Debt		74,286	75,000
Total Equity		(46,238)	(45,762)
Company's Investment	[1]	(22,021)	(21,931)
SUMMARY OF OPERATIONS:
Total Revenues		12,291	11,945	11,829
Net Income (Loss)		2,820	2,775	2,827
Company's Share of Income (Loss)		1,416	1,407	1,372
Other [Member]
SUMMARY OF FINANCIAL POSITION:
Total Assets		0	1,411
Total Debt		0	0
Total Equity		0	979
Company's Investment		0	2
SUMMARY OF OPERATIONS:
Total Revenues		0	4,841	48,394
Net Income (Loss)		0	7,831	58,710
Company's Share of Income (Loss)		$ (14)	$ 3,807	$ 64,447

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