Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	$ 206,997	$ 195,495	$ 617,216	$ 564,802
Total Net Operating Income	140,663	134,928	427,091	391,820
Reconciliation to net income:
Depreciation and amortization	(73,057)	(66,547)	(212,466)	(189,423)
Impairments of real estate assets	(1,515)	0	(36,515)	0
General and administrative expenses	(9,586)	(10,350)	(32,733)	(30,409)
Interest expense	(26,392)	(21,986)	(75,812)	(60,755)
Other income	138	424	621	1,068
Gains on disposition of property	9,402	38,572	63,546	80,371
Equity in earnings of unconsolidated affiliates	457	546	1,083	1,614
Net income	40,110	75,587	134,815	194,286
Total Office Segment [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	192,532	178,350	570,443	512,360
Total Net Operating Income	132,103	124,964	399,130	360,548
Office Atlanta, GA [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	35,804	36,672	106,805	108,385
Total Net Operating Income	22,524	24,157	69,472	71,779
Office Charlotte, NC [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	18,825	14,313	52,643	32,364
Total Net Operating Income	14,275	11,159	40,132	25,446
Office Nashville, TN [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	44,587	36,136	130,640	106,873
Total Net Operating Income	33,154	27,355	97,093	78,172
Office Orlando, FL [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	13,634	12,852	40,298	38,141
Total Net Operating Income	7,865	7,920	24,264	23,414
Office Raleigh, NC [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	45,220	42,471	137,051	117,168
Total Net Operating Income	32,822	31,425	101,557	88,005
Office Richmond, VA [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	10,872	12,050	31,837	35,263
Total Net Operating Income	7,112	7,805	21,700	24,092
Office Tampa, FL [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	23,590	23,856	71,169	74,166
Total Net Operating Income	14,351	15,143	44,912	49,640
Other [Member]
Segment Reporting Information [Line Items]
Total Rental and Other Revenues	14,465	17,145	46,773	52,442
Total Net Operating Income	$ 8,560	$ 9,964	$ 27,961	$ 31,272