Statements of Cash Flows Statement - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Operating activities:
Net loss attributable to the Company	$ (3,494,000)	$ (2,078,000)	$ (195,560,000)	$ (5,956,000)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(3,602,000)	(2,137,000)	(199,075,000)	(6,094,000)
Reconciliation of net loss to net cash provided by (used in) operating activities:
Depreciation expense	51,794,000	46,239,000	153,096,000	137,191,000
Amortization of above and below Market Leases			(6,145,000)	(4,525,000)
Deferred fee income amortization			(3,710,000)	(4,720,000)
amortization of purchase option termination fee income	(421,000)	(1,283,000)	(4,896,000)	(6,900,000)
Interest Income, Securities, Mortgage Backed	0	0	0	(95,000)
Deferred Sales Inducement Cost, Amortization Expense			3,027,000	2,414,000
Deferred loan cost amortization			5,177,000	4,752,000
deferred interest income			(9,208,000)	(10,206,000)
Receipt of accrued interest income on real estate loans			10,179,000	2,318,000
Gain (Loss) on Sale of Mortgage Loans			0	(751,000)
Share-based Compensation	(152,000)	0	5,463,000	0
Gain (Loss) on Disposition of Assets			(3,789,000)	0
Gain (Loss) From Unconsolidated Joint Ventures			120,000	0
cash inflows purchase option terminations			4,800,000	1,330,000
Gain (Loss) on Extinguishment of Debt	518,000	15,000	6,674,000	84,000
noncash loan interest income			0	(637,000)
Provision for Loan and Lease Losses			5,463,000	0
cash inflows mortgage interest from consolidated VIE			0	13,398,000
mortgage interes cash outflows consolidated VIE			0	(13,398,000)
Changes in operating assets and liabilities:
(Increase) in tenant accounts receivable			(15,769,000)	(12,379,000)
Payments for (Proceeds from) Tenant Allowance			(382,000)	(570,000)
Loans and Leases Receivable, Allowance	0	5,530,000	1,963,000	16,144,000
(Increase) decrease in other assets			46,821,000	22,399,000
Increase (Decrease) in Deferred Liabilities			22,851,000	0
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			15,013,000	0
Increase in accounts payable and accrued expenses			(249,000)	730,000
Net cash provided by (used in) operating activities			29,998,000	124,436,000
Investing activities:
Investments in real estate loans			(42,193,000)	(74,668,000)
Proceeds from Principal Repayments on Loans and Leases Held-for-investment			71,146,000	0
Notes receivable issued			15,012,000	2,169,000
Deferred acquisition fee on real estate loans			(9,624,000)	(30,434,000)
Deferred real estate loan income			(793,000)	(5,399,000)
Acquisition of properties, net			(185,970,000)	(442,415,000)
proceeds from sale of interest in joint venture			19,221,000	0
return of capital from joint venture			12,250,000	0
Receipt of insurance proceeds for capital improvements			0	746,000
Proceeds from Sale of Productive Assets			787,000	0
Additions to real estate assets - improvements			(39,158,000)	(34,251,000)
Payments to Acquire Investments			(50,000)	0
Increase (Decrease) in Earnest Money Deposits Outstanding			(1,227,000)	(952,000)
AcquisitionFeesRelatedPartyCosts			0	(674,000)
Payments to Acquire Mortgage Backed Securities (MBS) categorized as Held-to-maturity			0	(18,656,000)
cash paid investment in CMBS			0	(12,278,000)
Proceeds from Sale of Mortgage Backed Securities (MBS) categorized as Available-for-sale			0	53,445,000
mortgage principal received from consolidated VIE			0	5,024,000
Increase (Decrease) in Accounts and Notes Receivable			4,546,000	26,222,000
Proceeds from Sale of Loans Receivable				747,000
Net cash (used in) investing activities			(155,171,000)	(530,027,000)
Financing activities:
Proceeds from mortgage notes payable			377,749,000	329,905,000
Extinguishment of Debt, Amount			(173,409,000)	(106,728,000)
Payments for mortgage loan costs			(10,911,000)	(6,738,000)
Payments of Debt Issuance Costs			(5,733,000)	0
payments received from real estate loan participants			0	(5,223,000)
Proceeds from non-revolving lines of credit			321,000,000	240,200,000
Payments on revolving lines of credit			(288,000,000)	(247,200,000)
Repayments of Short-term Debt			(70,000,000)	0
mortgage principal paid to consolidated VIE			0	(5,024,000)
cash flows financing proceeds repurchase agreements			0	4,857,000
cash flows financing repayments repurchase agreements			0	(4,857,000)
Proceeds from sales of Units, net of offering costs			159,096,000	380,016,000
Proceeds from Warrant Exercises			24,000	9,875,000
Preferred Stock, Redemption Amount			(82,003,000)	(7,995,000)
Dividends declared and paid			(33,271,000)	(33,617,000)
Proceeds from Issuance of Common Stock			4,522,000	0
Payments of Ordinary Dividends, Preferred Stock and Preference Stock			(104,428,000)	(81,025,000)
Payments for deferred offering costs, net of non cash items			(10,669,000)	(3,386,000)
Proceeds from Noncontrolling Interests			99,000	2,050,000
Net Cash Provided by (Used in) Financing Activities			83,947,000	465,110,000
Cash and Cash Equivalents, Period Increase (Decrease)			(41,226,000)	59,519,000
Cash beginning of period			137,253,000	87,690,000	$ 87,690,000
Cash end of period	96,027,000	147,209,000	96,027,000	147,209,000	137,253,000
Supplemental cash flow information:
Cash paid for interest			84,172,000	76,563,000
Noncash Investing and Financing Items [Abstract]
Accrued capital expenditures			6,067,000	3,952,000
Deemed noncash dividend			499,000	358,000
Dividends payable to non controlling interests			130,000	225,000
Payments of Ordinary Dividends, Noncontrolling Interest			119,000	0
Accrued and payable deferred offering costs			38,000	252,000
receivable for deferred offering costs			2,473,000	210,000
Writeoff of fully amortized deferred loan costs			2,828,000	1,850,000
Assets	4,731,062,000		4,731,062,000		4,770,560,000
Liabilities	3,060,204,000		3,060,204,000		$ 2,836,444,000
Notes Reduction			20,865,000	0
Reclass of offering costs from deferred asset to equity			4,338,000	7,508,000
Loan Receivable Transferred To Equity			0	47,797,000
Non-Cash Contribution of Property into an Unconsolidated Joint Venture			38,443,000	0
Loans Assumed			0	41,550,000
Share-based Compensation			6,461,000	719,000
Noncash settlement of loans			40,000	384,000
loan fees received			882,000	1,347,000
mortgage debt refinanced			86,669,000	65,607,000
Operating Lease Assumed			15,912,000	0
Variable Interest Entity, Primary Beneficiary
Noncash Investing and Financing Items [Abstract]
Assets	0	270,669,000	0	270,669,000
Liabilities	0	270,669,000	0	270,669,000
Common Stock [Member]
Noncash Investing and Financing Items [Abstract]
Dividends payable			8,876,000	11,823,000
Series A Preferred Stock [Member]
Noncash Investing and Financing Items [Abstract]
Dividends payable			9,954,000	9,534,000
Series M Preferred Stock [Member]
Noncash Investing and Financing Items [Abstract]
Dividends payable			1,097,000	714,000
Series A1/M1 Preferred Stock
Financing activities:
Proceeds from Issuance of Common Stock	4,614,000
Noncash Investing and Financing Items [Abstract]
Dividends payable			545,000	0
Parent [Member]
Operating activities:
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(3,494,000)	$ (2,078,000)	$ (195,560,000)	$ (5,956,000)
Parent [Member] | Series A1/M1 Preferred Stock
Financing activities:
Proceeds from Issuance of Common Stock	$ 4,614,000