Reportable Segments - Segment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Total Revenues	$ 185,680	$ 186,637	$ 372,578	$ 376,187
Rental property revenues
Segment Reporting Information [Line Items]
Total Revenues	183,174	181,766	366,401	366,573
Rental property revenues | Office
Segment Reporting Information [Line Items]
Total Revenues	181,873	181,175	364,115	365,421
Rental property revenues | Non-Office
Segment Reporting Information [Line Items]
Total Revenues	1,301	591	2,286	1,152
Rental property revenues | Operating segments
Segment Reporting Information [Line Items]
Total Revenues	187,266	189,908	374,652	381,953
Rental property revenues | Operating segments | Atlanta
Segment Reporting Information [Line Items]
Total Revenues	69,299	66,022	137,736	131,172
Rental property revenues | Operating segments | Austin
Segment Reporting Information [Line Items]
Total Revenues	59,054	59,677	120,278	117,710
Rental property revenues | Operating segments | Charlotte
Segment Reporting Information [Line Items]
Total Revenues	15,230	22,475	29,719	44,203
Rental property revenues | Operating segments | Dallas
Segment Reporting Information [Line Items]
Total Revenues	4,132	4,531	8,328	9,014
Rental property revenues | Operating segments | Phoenix
Segment Reporting Information [Line Items]
Total Revenues	13,533	12,482	26,963	25,220
Rental property revenues | Operating segments | Tampa
Segment Reporting Information [Line Items]
Total Revenues	17,216	14,165	34,140	28,736
Rental property revenues | Operating segments | Other markets
Segment Reporting Information [Line Items]
Total Revenues	8,802	10,556	17,488	25,898
Rental property revenues | Operating segments | Office
Segment Reporting Information [Line Items]
Total Revenues	184,346	187,391	368,966	377,356
Rental property revenues | Operating segments | Office | Atlanta
Segment Reporting Information [Line Items]
Total Revenues	68,860	65,626	136,875	130,502
Rental property revenues | Operating segments | Office | Austin
Segment Reporting Information [Line Items]
Total Revenues	59,054	59,677	120,278	117,710
Rental property revenues | Operating segments | Office | Charlotte
Segment Reporting Information [Line Items]
Total Revenues	13,929	21,884	27,433	43,051
Rental property revenues | Operating segments | Office | Dallas
Segment Reporting Information [Line Items]
Total Revenues	4,132	4,531	8,328	9,014
Rental property revenues | Operating segments | Office | Phoenix
Segment Reporting Information [Line Items]
Total Revenues	13,533	12,482	26,963	25,220
Rental property revenues | Operating segments | Office | Tampa
Segment Reporting Information [Line Items]
Total Revenues	17,216	14,165	34,140	28,736
Rental property revenues | Operating segments | Office | Other markets
Segment Reporting Information [Line Items]
Total Revenues	7,622	9,026	14,949	23,123
Rental property revenues | Operating segments | Non-Office
Segment Reporting Information [Line Items]
Total Revenues	2,920	2,517	5,686	4,597
Rental property revenues | Operating segments | Non-Office | Atlanta
Segment Reporting Information [Line Items]
Total Revenues	439	396	861	670
Rental property revenues | Operating segments | Non-Office | Austin
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Rental property revenues | Operating segments | Non-Office | Charlotte
Segment Reporting Information [Line Items]
Total Revenues	1,301	591	2,286	1,152
Rental property revenues | Operating segments | Non-Office | Dallas
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Rental property revenues | Operating segments | Non-Office | Phoenix
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Rental property revenues | Operating segments | Non-Office | Tampa
Segment Reporting Information [Line Items]
Total Revenues	0	0	0	0
Rental property revenues | Operating segments | Non-Office | Other markets
Segment Reporting Information [Line Items]
Total Revenues	1,180	1,530	2,539	2,775
Rental property revenues | Segment reconciling items
Segment Reporting Information [Line Items]
Total Revenues	(4,092)	(8,142)	(8,251)	(15,380)
Rental property revenues | Segment reconciling items | Office
Segment Reporting Information [Line Items]
Total Revenues	(2,473)	(6,216)	(4,851)	(11,935)
Rental property revenues | Segment reconciling items | Non-Office
Segment Reporting Information [Line Items]
Total Revenues	$ (1,619)	$ (1,926)	$ (3,400)	$ (3,445)