Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Abstract]
Rental and other revenues	$ 833,997	$ 828,929	$ 768,007
Total net operating income	565,215	569,123	531,571
Reconciliation to net income:
Depreciation and amortization	(299,411)	(287,610)	(259,255)
Impairments of real estate assets	0	(36,515)	0
General and administrative expenses	(42,857)	(42,266)	(40,553)
Interest expense	(136,710)	(105,385)	(85,853)
Other income	4,435	1,530	1,394
Gains on disposition of property	47,773	63,546	174,059
Gain on deconsolidation of affiliate	11,778	0	0
Equity in earnings of unconsolidated affiliates	1,107	1,535	1,947
Net income	151,330	163,958	323,310
Total Assets	6,002,928	6,063,376
Office Total Segment [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	776,827	767,568	699,924
Total net operating income	533,600	533,008	491,053
Reconciliation to net income:
Total Assets	5,315,397	5,470,529
Office Atlanta, GA [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	143,741	143,904	143,612
Total net operating income	89,700	92,297	94,122
Reconciliation to net income:
Total Assets	907,421	928,406
Office Charlotte, NC [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	85,984	73,721	49,347
Total net operating income	63,921	55,689	38,464
Reconciliation to net income:
Total Assets	974,846	984,075
Office Nashville, TN [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	171,797	174,341	149,674
Total net operating income	125,417	129,217	110,039
Reconciliation to net income:
Total Assets	1,259,272	1,290,819
Office Orlando, FL [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	58,002	54,802	51,281
Total net operating income	35,162	32,331	31,301
Reconciliation to net income:
Total Assets	286,781	287,950
Office Raleigh, NC [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	181,964	182,990	162,115
Total net operating income	132,262	134,904	121,005
Reconciliation to net income:
Total Assets	1,255,978	1,288,878
Office Richmond, VA [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	35,918	43,084	45,941
Total net operating income	24,756	28,879	31,726
Reconciliation to net income:
Total Assets	157,299	196,435
Office Tampa, FL [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	99,421	94,726	97,954
Total net operating income	62,382	59,691	64,396
Reconciliation to net income:
Total Assets	473,800	493,966
Other Segment [Member]
Segment Reporting Information [Abstract]
Rental and other revenues	57,170	61,361	68,083
Total net operating income	31,615	36,115	$ 40,518
Reconciliation to net income:
Total Assets	$ 687,531	$ 592,847