Investment in Unconsolidated Joint Ventures - Summary of Financial Position and Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
SUMMARY OF FINANCIAL POSITION:
Total Assets	$ 6,977,364		$ 6,977,364		$ 7,107,398
Total Equity (Deficit)	4,445,092		4,445,092		4,467,134
SUMMARY OF OPERATIONS:
Total Revenues	188,732	$ 183,380	564,919	$ 557,193
Net Income (Loss)	54,018	$ 28,115	111,281	226,159
Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	533,377		533,377		590,853
Total Debt	317,444		317,444		230,305
Total Equity (Deficit)	187,752		187,752		244,186
Company’s Investment	76,354		76,354		107,192
SUMMARY OF OPERATIONS:
Total Revenues			50,805	45,041
Net Income (Loss)			12,571	12,002
Company's Share of Income (Loss)			5,826	6,751
Neuhoff Holdings LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	111,250		111,250		0
Total Debt	26,932		26,932		0
Total Equity (Deficit)	84,318		84,318		0
Company’s Investment	42,159		42,159		0
Austin 300 Colorado Project, LP | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	173,515		173,515		165,586
Total Debt	92,252		92,252		86,848
Total Equity (Deficit)	70,167		70,167		68,567
Company’s Investment	38,919		38,919		38,488
SUMMARY OF OPERATIONS:
Total Revenues			6,388	264
Net Income (Loss)			1,600	90
Company's Share of Income (Loss)			773	45
AMCO 120 WT Holdings, LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	84,640		84,640		85,449
Total Debt	0		0		0
Total Equity (Deficit)	83,406		83,406		84,311
Company’s Investment	15,450		15,450		15,735
SUMMARY OF OPERATIONS:
Total Revenues			6,385	1,564
Net Income (Loss)			234	(2,106)
Company's Share of Income (Loss)			38	(383)
HICO Victory Center LP | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	16,230		16,230		16,544
Total Debt	0		0		0
Total Equity (Deficit)	15,929		15,929		15,709
Company’s Investment	10,709		10,709		10,595
SUMMARY OF OPERATIONS:
Total Revenues			199	241
Net Income (Loss)			199	241
Company's Share of Income (Loss)			111	121
715 Ponce Holdings LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	8,051		8,051		0
Total Debt	0		0		0
Total Equity (Deficit)	8,016		8,016		0
Company’s Investment	4,028		4,028		0
SUMMARY OF OPERATIONS:
Total Revenues			25	0
Net Income (Loss)			11	0
Company's Share of Income (Loss)			7	0
DC Charlotte Plaza LLLP | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	0		0		173,704
Total Debt	0		0		0
Total Equity (Deficit)	0		0		90,648
Company’s Investment	6		6		47,941
SUMMARY OF OPERATIONS:
Total Revenues			15,209	15,476
Net Income (Loss)			5,494	5,597
Company's Share of Income (Loss)			2,549	2,583
Carolina Square Holdings LP | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	113,129		113,129		118,616
Total Debt	133,264		133,264		77,034
Total Equity (Deficit)	(33,999)		(33,999)		21,888
Company’s Investment	(15,671)		(15,671)		12,430
SUMMARY OF OPERATIONS:
Total Revenues			12,478	10,792
Net Income (Loss)			1,713	1,936
Company's Share of Income (Loss)			776	950
Crawford Long - CPI, LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	26,450		26,450		29,641
Total Debt	64,996		64,996		66,423
Total Equity (Deficit)	(40,203)		(40,203)		(38,253)
Company’s Investment	(19,326)		(19,326)		(18,289)
SUMMARY OF OPERATIONS:
Total Revenues			9,743	9,784
Net Income (Loss)			3,049	2,767
Company's Share of Income (Loss)			1,412	1,329
Other | Equity Method Investment, Nonconsolidated Investee or Group of Investees
SUMMARY OF FINANCIAL POSITION:
Total Assets	112		112		1,313
Total Debt	0		0		0
Total Equity (Deficit)	118		118		1,316
Company’s Investment	$ 80		80		$ 292
SUMMARY OF OPERATIONS:
Total Revenues			378	6,920
Net Income (Loss)			271	3,477
Company's Share of Income (Loss)			$ 160	$ 2,106