Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	$ 207,291	$ 203,841	$ 420,043	$ 410,219
Total Net Operating Income	140,984	141,472	288,005	286,428
Reconciliation to net income:
Depreciation and amortization	(75,018)	(69,742)	(145,651)	(139,409)
Impairments of real estate assets	0	(35,000)	0	(35,000)
General and administrative expenses	(9,380)	(9,591)	(21,795)	(23,147)
Interest expense	(34,063)	(25,027)	(67,161)	(49,420)
Other income	1,181	120	2,328	483
Gains on disposition of property	19,368	50,044	19,818	54,144
Gain on deconsolidation of affiliate	0	0	11,778	0
Equity in earnings of unconsolidated affiliates	798	326	1,502	626
Net income	43,870	52,602	88,824	94,705
Total Office Segment [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	193,136	187,802	391,122	377,911
Total Net Operating Income	133,116	131,751	271,828	267,027
Office Atlanta, GA [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	35,455	35,447	72,325	71,001
Total Net Operating Income	22,268	23,267	46,493	46,948
Office Charlotte, NC [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	20,793	16,874	42,373	33,818
Total Net Operating Income	15,221	12,807	31,331	25,857
Office Nashville, TN [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	42,636	42,606	87,200	86,053
Total Net Operating Income	31,116	31,417	64,141	63,939
Office Orlando, FL [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	14,550	13,352	28,944	26,664
Total Net Operating Income	8,852	8,262	17,624	16,399
Office Raleigh, NC [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	45,701	45,535	91,579	91,831
Total Net Operating Income	33,670	34,020	67,276	68,735
Office Richmond, VA [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	9,048	10,432	18,357	20,965
Total Net Operating Income	6,353	7,363	12,923	14,588
Office Tampa, FL [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	24,953	23,556	50,344	47,579
Total Net Operating Income	15,636	14,615	32,040	30,561
Other [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	14,155	16,039	28,921	32,308
Total Net Operating Income	$ 7,868	$ 9,721	$ 16,177	$ 19,401