Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 1,142,000	$ 379,758,000	$ 34,565,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Deferred rent and amortization of intangible assets, liabilities and lease inducements	(3,636,000)	(2,172,000)	(6,584,000)
Depreciation and amortization	53,228,000	58,364,000	71,968,000
Reclassification from AOCI to interest expense	(1,552,000)	0	0
Change in fair value of swaps	1,728,000	0	0
Transfer of right to collect supplemental real estate tax reimbursements	0	(5,097,000)	0
Gain on sale of real estate	0	(401,737,000)	(39,666,000)
Impairment of real estate	0	13,100,000	0
Straight-line rent, below-market ground lease and amortization of intangible assets	(18,000)	1,069,000	1,766,000
Straight-line lease termination income	0	(362,000)	0
Amortization of deferred loan costs	1,704,000	2,870,000	2,803,000
Amortization of premiums and discounts on debt	(444,000)	(590,000)	(870,000)
Unrealized premium adjustment	2,522,000	2,447,000	1,599,000
Amortization and accretion on loans receivable, net	(41,000)	96,000	(1,039,000)
Bad debt expense	494,000	677,000	161,000
Deferred income taxes	(3,000)	271,000	164,000
Stock-based compensation	162,000	154,000	164,000
Loans funded, held for sale to secondary market	(55,655,000)	(57,237,000)	(38,234,000)
Proceeds from sale of guaranteed loans	54,142,000	51,312,000	38,536,000
Principal collected on loans subject to secured borrowings	5,698,000	6,674,000	3,866,000
Other operating activity	(1,587,000)	(1,718,000)	136,000
Changes in operating assets and liabilities:
Accounts receivable and interest receivable	6,692,000	(977,000)	(2,569,000)
Other assets	(2,728,000)	(19,762,000)	419,000
Accounts payable and accrued expenses	(365,000)	(14,139,000)	630,000
Deferred leasing costs	(5,773,000)	(6,973,000)	(19,885,000)
Other liabilities	2,221,000	(5,589,000)	3,219,000
Due to related parties	2,218,000	(1,584,000)	724,000
Net cash provided by (used in) operating activities	60,149,000	(1,145,000)	51,873,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to investments in real estate	(12,055,000)	(21,101,000)	(35,414,000)
Acquisition of real estate	(112,048,000)	(19,631,000)	0
Proceeds from sale of real estate, net	0	1,012,115,000	94,568,000
Proceeds from sale of assets held for sale, net	0	0	25,690,000
Loans funded	(18,579,000)	(19,079,000)	(66,001,000)
Principal collected on loans	10,770,000	10,883,000	33,470,000
Other investing activity	178,000	317,000	1,287,000
Net cash (used in) provided by investing activities	(131,734,000)	963,504,000	53,600,000
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from mortgages payable	0	0	392,000,000
Payment of mortgages payable	0	(65,877,000)	(4,354,000)
Proceeds from unsecured revolving lines of credit, revolving credit facilities and term notes	180,000,000	120,000,000	175,000,000
Payment of unsecured revolving lines of credit, revolving credit facilities and term notes	(220,000,000)	(335,000,000)	(282,000,000)
Proceeds from SBA 7(a) loan-backed notes	38,200,000	0	0
Payment of principal on loan-backed notes	(4,431,000)	0	0
Payment of principal on secured borrowings	(5,698,000)	(6,674,000)	(13,946,000)
Proceeds from secured borrowings	772,000	0	25,791,000
Payment of deferred preferred stock offering costs	(1,136,000)	(3,832,000)	(1,960,000)
Payment of other deferred costs	(235,000)	0	0
Payment of deferred loan costs	(4,234,000)	(304,000)	(1,994,000)
Payment of common dividends	(21,895,000)	(38,327,000)	(77,316,000)
Payment of special cash dividends	(1,575,000)	(4,872,000)	0
Repurchase of Common Stock	0	(886,010,000)	(290,134,000)
Payment of borrowing costs	0	(8,000)	0
Net proceeds from issuance of Series A Preferred Warrants	73,000	127,000	5,000
Payment of preferred stock dividends	(2,173,000)	(250,000)	0
Redemption of Series A Preferred Stock	(113,000)	(27,000)	0
Noncontrolling interests' distributions	(74,000)	(43,000)	(43,000)
Net cash used in financing activities	(6,535,000)	(982,650,000)	(77,522,000)
Change in cash balances included in assets held for sale	(755,000)	0	1,471,000
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS AND RESTRICTED CASH	(78,875,000)	(20,291,000)	29,422,000
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Beginning of period	156,318,000	176,609,000	147,187,000
End of period	77,443,000	156,318,000	176,609,000
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH TO THE CONSOLIDATED BALANCE SHEETS:
Total cash and cash equivalents and restricted cash	156,318,000	176,609,000	147,187,000
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid during the period for interest	27,473,000	35,092,000	33,060,000
Federal income taxes paid	622,000	1,595,000	1,353,000
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Additions to investments in real estate included in accounts payable and accrued expenses	11,875,000	9,024,000	4,527,000
Net increase in fair value of derivatives applied to other comprehensive income	1,727,000	2,140,000	2,010,000
Reduction of loans receivable and secured borrowings due to the SBA's repurchase of the guaranteed portion of loans	0	534,000	2,663,000
Additions to deferred loan costs included in accounts payable and accrued expenses	32,000	0	0
Additions to deferred costs included in accounts payable and accrued expenses	174,000	0	0
Additions to preferred stock offering costs included in accounts payable and accrued expenses	172,000	388,000	238,000
Preferred stock offering costs offset against redeemable preferred stock in temporary equity	229,000	122,000	3,000
Preferred stock offering costs offset against redeemable preferred stock in permanent equity	0	2,532,000	0
Reclassification of Series A Preferred Stock from temporary equity to permanent equity	27,887,000	1,417,000	0
Reclassification of Series A Preferred Stock from temporary equity to accounts payable and accrued expenses	0	13,000	0
Accrual reversed to lease termination income	0	480,000	0
Series A Preferred Stock
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of Preferred Stock	35,984,000	28,070,000	1,429,000
Series L Preferred Stock
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of Preferred Stock	$ 0	$ 210,377,000	$ 0