Investment in Unconsolidated Joint Ventures - Summary of Financial Position and Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	$ 7,312,034	$ 7,107,398
Total Equity (Deficit)	4,566,770	4,467,134
Income Statement [Abstract]
Total Revenues	755,073	740,340	$ 657,515
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	380,046	590,853
Total Debt	225,610	230,192
Total Equity (Deficit)	125,793	244,186
Company's Investment	42,669	107,192
Income Statement [Abstract]
Total Revenues	63,239	62,859	104,471
Net Income (Loss)	14,917	21,409	25,685
Company's Income (Loss) from Investment	6,801	7,947	12,666
AMCO 120 WT Holdings, LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	83,546	85,449
Total Debt	0	0
Total Equity (Deficit)	82,739	84,311
Company's Investment	15,347	15,735
Income Statement [Abstract]
Total Revenues	8,894	3,000	40
Net Income (Loss)	639	2,740	(341)
Company's Income (Loss) from Investment	115	(552)	(68)
Carolina Square Holdings LP | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	113,011	118,616
Total Debt	132,654	77,034
Total Equity (Deficit)	(34,066)	21,888
Company's Investment	(15,786)	12,430
Income Statement [Abstract]
Total Revenues	16,518	14,581	12,344
Net Income (Loss)	2,187	3,061	470
Company's Income (Loss) from Investment	982	1,472	133
Crawford Long - CPI, LLC
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Debt	64,600
Crawford Long - CPI, LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	24,709	29,641
Total Debt	64,566	66,310
Total Equity (Deficit)	(40,221)	(38,253)
Company's Investment	(19,356)	(18,289)
Income Statement [Abstract]
Total Revenues	13,118	12,650	12,664
Net Income (Loss)	4,032	3,797	3,897
Company's Income (Loss) from Investment	1,869	1,808	1,866
Neuhoff Holdings LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	133,691	0
Total Debt	28,390	0
Total Equity (Deficit)	93,218	0
Company's Investment	47,529	0
Income Statement [Abstract]
Total Revenues	51	0	0
Net Income (Loss)	51	0	0
Company's Income (Loss) from Investment	25	0	0
715 Ponce Holdings LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	8,150	0
Total Debt	0	0
Total Equity (Deficit)	8,150	0
Company's Investment	4,165	0
Income Statement [Abstract]
Total Revenues	84	0	0
Net Income (Loss)	55	0	0
Company's Income (Loss) from Investment	27	0	0
HICO Victory Center LP | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	16,421	16,544
Total Debt	0	0
Total Equity (Deficit)	15,962	15,709
Company's Investment	10,723	10,595
Income Statement [Abstract]
Total Revenues	232	356	513
Net Income (Loss)	232	356	513
Company's Income (Loss) from Investment	125	178	276
Austin 300 Colorado Project, LP (purchased outside interest December 2021) | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	0	165,586
Total Debt	0	86,848
Total Equity (Deficit)	0	68,567
Company's Investment	0	38,488
Income Statement [Abstract]
Total Revenues	8,747	841	422
Net Income (Loss)	2,012	466	199
Company's Income (Loss) from Investment	972	233	100
Charlotte Gateway Village, LLC (sold March 2020) | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Income Statement [Abstract]
Total Revenues	378	6,692	27,708
Net Income (Loss)	369	3,202	10,285
Company's Income (Loss) from Investment	185	1,658	5,143
DC Charlotte Plaza LLLP (sold September 2021) | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	0	173,704
Total Debt	0	0
Total Equity (Deficit)	0	90,648
Company's Investment	0	47,941
Income Statement [Abstract]
Total Revenues	15,217	20,439	15,636
Net Income (Loss)	5,491	7,272	5,894
Company's Income (Loss) from Investment	2,539	3,380	2,947
Terminus Office Holdings LLC (purchased outside interest October 2019) | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Income Statement [Abstract]
Total Revenues	0	0	34,964
Net Income (Loss)	0	0	4,962
Company's Income (Loss) from Investment	0	(23)	2,381
Other | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Equity Method Investment Summarized Financial Information Financial Position [Abstract]
Total Assets	518	1,313
Total Debt	0	0
Total Equity (Deficit)	11	1,316
Company's Investment	47	292
Income Statement [Abstract]
Total Revenues	0	4,300	180
Net Income (Loss)	(151)	515	(194)
Company's Income (Loss) from Investment	$ (38)	$ (207)	$ (112)