Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net (loss) income	$ (7,506,000)	$ 71,982,000	$ 80,867,000
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization (including below-market ground leases)	50,378,000	55,394,000	52,819,000
Amortization of deferred financing costs	2,095,000	2,052,000	1,950,000
Loss on extinguishment of debt	0	10,827,000	0
Unrealized loss on other real estate related investments	7,102,000	0	0
Amortization of stock-based compensation	5,758,000	10,832,000	3,790,000
Straight-line rental income	(17,000)	(32,000)	(77,000)
Adjustment for collectibility of rental income	1,417,000	0	0
Noncash interest income	(1,165,000)	(155,000)	0
Loss on sale of real estate, net	3,769,000	77,000	37,000
Interest income distribution from other real estate investment	0	0	1,346,000
Impairment of real estate investments	79,062,000	0	0
Provision for loan losses, net	3,844,000	0	0
Change in operating assets and liabilities:
Accounts and other receivables	604,000	(562,000)	825,000
Prepaid expenses and other assets, net	123,000	399,000	387,000
Accounts payable, accrued liabilities and deferred rent liabilities	(1,049,000)	6,057,000	3,791,000
Net cash provided by operating activities	144,415,000	156,871,000	145,735,000
Cash flows from investing activities:
Acquisitions of real estate, net of deposits applied	(21,915,000)	(192,718,000)	(89,650,000)
Purchases of equipment, furniture and fixtures and improvements to real estate	(7,292,000)	(6,013,000)	(8,297,000)
Investment in real estate related investments and other loans receivable	(149,650,000)	(1,253,000)	(30,498,000)
Principal payments received on other loans receivable	6,308,000	393,000	80,928,000
Repayment of other real estate investment	0	0	2,327,000
Escrow deposits for potential acquisitions of real estate	0	0	(3,000,000)
Net proceeds from sales of real estate	45,149,000	6,958,000	6,608,000
Net cash used in investing activities	(127,400,000)	(192,633,000)	(41,582,000)
Cash flows from financing activities:
Proceeds from (costs paid for) the issuance of common stock, net	47,236,000	22,946,000	(404,000)
Proceeds from the issuance of senior unsecured notes payable	0	400,000,000	0
Borrowings under unsecured revolving credit facility	160,000,000	220,000,000	65,000,000
Payments on senior unsecured notes payable	0	(300,000,000)	0
Payments on unsecured revolving credit facility	(115,000,000)	(190,000,000)	(75,000,000)
Payments on debt extinguishment and deferred financing costs	(5,361,000)	(14,095,000)	0
Net-settle adjustment on restricted stock	(4,469,000)	(1,331,000)	(1,996,000)
Dividends paid on common stock	(106,138,000)	(100,782,000)	(93,161,000)
Net cash (used in) provided by financing activities	(23,732,000)	36,738,000	(105,561,000)
Net (decrease) increase in cash and cash equivalents	(6,717,000)	976,000	(1,408,000)
Cash and cash equivalents as of the beginning of period	19,895,000	18,919,000	20,327,000
Cash and cash equivalents as of the end of period	13,178,000	19,895,000	18,919,000
Supplemental disclosures of cash flow information:
Interest paid	25,912,000	22,838,000	21,691,000
Supplemental schedule of noncash investing and financing activities:
Increase in dividends payable	1,265,000	2,033,000	2,568,000
Right-of-use asset obtained in exchange for new operating lease obligation	0	0	599,000
Transfer of pre-acquisition costs to acquired assets	7,000	358,000	168,000
Sale of real estate settled with notes receivable	$ 12,000,000	$ 0	$ 32,400,000