Reportable Segments - Segment Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total Revenues	$ 762,290	$ 755,073	$ 740,340
Rental property revenues
Segment Reporting Information [Line Items]
Total Revenues	753,511	739,063	721,883
Rental property revenues | Office
Segment Reporting Information [Line Items]
Total Revenues	748,477	736,365	719,866
Rental property revenues | Non-Office
Segment Reporting Information [Line Items]
Total Revenues	5,034	2,698	2,017
Rental property revenues | Operating Segments
Segment Reporting Information [Line Items]
Total Revenues	768,448	767,856	750,217
Rental property revenues | Operating Segments | Atlanta
Segment Reporting Information [Line Items]
Total Revenues	280,209	270,412	256,196
Rental property revenues | Operating Segments | Austin
Segment Reporting Information [Line Items]
Total Revenues	249,776	247,806	210,229
Rental property revenues | Operating Segments | Charlotte
Segment Reporting Information [Line Items]
Total Revenues	60,346	77,402	96,537
Rental property revenues | Operating Segments | Dallas
Segment Reporting Information [Line Items]
Total Revenues	16,736	17,670	18,143
Rental property revenues | Operating Segments | Phoenix
Segment Reporting Information [Line Items]
Total Revenues	57,635	50,292	54,261
Rental property revenues | Operating Segments | Tampa
Segment Reporting Information [Line Items]
Total Revenues	70,984	59,614	50,671
Rental property revenues | Operating Segments | Other markets
Segment Reporting Information [Line Items]
Total Revenues	32,762	44,660	64,180
Rental property revenues | Operating Segments | Office
Segment Reporting Information [Line Items]
Total Revenues	757,692	758,440	742,703
Rental property revenues | Operating Segments | Office | Atlanta
Segment Reporting Information [Line Items]
Total Revenues	278,418	268,953	255,594
Rental property revenues | Operating Segments | Office | Austin
Segment Reporting Information [Line Items]
Total Revenues	249,776	247,806	210,229
Rental property revenues | Operating Segments | Office | Charlotte
Segment Reporting Information [Line Items]
Total Revenues	55,312	74,702	94,520
Rental property revenues | Operating Segments | Office | Dallas
Segment Reporting Information [Line Items]
Total Revenues	16,736	17,670	18,143
Rental property revenues | Operating Segments | Office | Phoenix
Segment Reporting Information [Line Items]
Total Revenues	57,635	50,292	50,671
Rental property revenues | Operating Segments | Office | Tampa
Segment Reporting Information [Line Items]
Total Revenues	70,984	59,614	54,261
Rental property revenues | Operating Segments | Office | Other markets
Segment Reporting Information [Line Items]
Total Revenues	28,831	39,403	59,285
Rental property revenues | Operating Segments | Non-Office
Segment Reporting Information [Line Items]
Total Revenues	10,756	9,416	7,514
Rental property revenues | Operating Segments | Non-Office | Atlanta
Segment Reporting Information [Line Items]
Total Revenues	1,791	1,459	602
Rental property revenues | Operating Segments | Non-Office | Austin
Segment Reporting Information [Line Items]
Total Revenues	0	0	0
Rental property revenues | Operating Segments | Non-Office | Charlotte
Segment Reporting Information [Line Items]
Total Revenues	5,034	2,700	2,017
Rental property revenues | Operating Segments | Non-Office | Dallas
Segment Reporting Information [Line Items]
Total Revenues	0	0	0
Rental property revenues | Operating Segments | Non-Office | Phoenix
Segment Reporting Information [Line Items]
Total Revenues	0	0	0
Rental property revenues | Operating Segments | Non-Office | Tampa
Segment Reporting Information [Line Items]
Total Revenues	0	0	0
Rental property revenues | Operating Segments | Non-Office | Other markets
Segment Reporting Information [Line Items]
Total Revenues	3,931	5,257	4,895
Rental property revenues | Segment Reconciling Items
Segment Reporting Information [Line Items]
Total Revenues	(14,937)	(28,793)	(28,334)
Rental property revenues | Segment Reconciling Items | Office
Segment Reporting Information [Line Items]
Total Revenues	(9,215)	(22,075)	(22,837)
Rental property revenues | Segment Reconciling Items | Non-Office
Segment Reporting Information [Line Items]
Total Revenues	$ (5,722)	$ (6,718)	$ (5,497)