Reportable Segments - Net Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Net Operating Income	$ 119,607	$ 123,124
Atlanta
Segment Reporting Information [Line Items]
Net Operating Income	44,408	43,196
Austin
Segment Reporting Information [Line Items]
Net Operating Income	36,367	34,278
Charlotte
Segment Reporting Information [Line Items]
Net Operating Income	10,654	15,257
Dallas
Segment Reporting Information [Line Items]
Net Operating Income	3,308	3,551
Phoenix
Segment Reporting Information [Line Items]
Net Operating Income	8,975	9,025
Tampa
Segment Reporting Information [Line Items]
Net Operating Income	10,691	9,402
Other markets
Segment Reporting Information [Line Items]
Net Operating Income	5,204	8,415
Office
Segment Reporting Information [Line Items]
Net Operating Income	117,820	121,839
Office | Atlanta
Segment Reporting Information [Line Items]
Net Operating Income	44,173	43,045
Office | Austin
Segment Reporting Information [Line Items]
Net Operating Income	36,367	34,278
Office | Charlotte
Segment Reporting Information [Line Items]
Net Operating Income	10,011	14,997
Office | Dallas
Segment Reporting Information [Line Items]
Net Operating Income	3,308	3,551
Office | Phoenix
Segment Reporting Information [Line Items]
Net Operating Income	8,975	9,025
Office | Tampa
Segment Reporting Information [Line Items]
Net Operating Income	10,691	9,402
Office | Other markets
Segment Reporting Information [Line Items]
Net Operating Income	4,295	7,541
Non-Office
Segment Reporting Information [Line Items]
Net Operating Income	1,787	1,285
Non-Office | Atlanta
Segment Reporting Information [Line Items]
Net Operating Income	235	151
Non-Office | Austin
Segment Reporting Information [Line Items]
Net Operating Income	0	0
Non-Office | Charlotte
Segment Reporting Information [Line Items]
Net Operating Income	643	260
Non-Office | Dallas
Segment Reporting Information [Line Items]
Net Operating Income	0	0
Non-Office | Phoenix
Segment Reporting Information [Line Items]
Net Operating Income	0	0
Non-Office | Tampa
Segment Reporting Information [Line Items]
Net Operating Income	0	0
Non-Office | Other markets
Segment Reporting Information [Line Items]
Net Operating Income	$ 909	$ 874