CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
OPERATING ACTIVITIES:
Net income	$ 11,114	$ 13,850	$ 17,665	$ 12,338	$ 63,722	$ 43,294	$ 78,012
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization						28,847	29,232
Stock-based compensation expense						5,785	5,231
Impairment charges							941
Gain on sale of real estate, net	(2,702)			(30)		(7,392)	(44,073)
Loss on unconsolidated joint ventures							620
Income from unconsolidated joint ventures						(1,041)	(287)
Income distributions from unconsolidated joint ventures							249
Straight-line rental income	44			(228)		(619)	(1,701)
Adjustment for collectibility of rental income and lease incentives				5,472		758	23,214
Lease incentives funded						(650)	(50)
Amortization of lease incentives	158			108		386	317
Provision (recovery) for credit losses	68			(2)		59	(1)
Other non-cash items, net						782	772
Increase in interest receivable						(4,730)	(4,662)
Decrease in accrued interest payable						(1,044)	(1,683)
Net change in other assets and liabilities						5,146	(502)
Net cash provided by operating activities						69,581	85,629
INVESTING ACTIVITIES:
Investment in real estate properties							(13,581)
Investment in real estate developments							(13,384)
Investment in real estate capital improvements						(4,839)	(3,955)
Capitalized interest							(354)
Proceeds from sale of real estate, net						43,628	72,141
Investment in real estate mortgage loans receivable						(2,081)	(4,176)
Principal payments received on mortgage loans receivable						625	565
Investments in unconsolidated joint ventures						(5,676)	(6,398)
Proceeds from liquidation of investments in unconsolidated joint ventures							17,758
Advances and originations under notes receivable						(6,453)	(1,366)
Principal payments received on notes receivable						2,553	4,732
Net cash provided by investing activities						27,757	51,982
FINANCING ACTIVITIES:
Bank borrowings						92,500	24,000
Repayment of bank borrowings						(48,000)	(28,000)
Principal payments on senior unsecured notes						(32,160)	(25,160)
Stock repurchase plan							(18,012)
Distributions paid to stockholders						(68,051)	(67,894)
Contribution from non-controlling interests						9
Distributions paid to non-controlling interests						(271)	(371)
Financing costs paid						(35)	(35)
Cash paid for taxes in lieu of shares upon vesting of restricted stock and performance-based stock units						(3,573)	(3,564)
Other						(70)	(8)
Net cash used in financing activities						(59,651)	(119,044)
(Decrease) increase in cash, cash equivalents and restricted cash						37,687	18,567
Cash, cash equivalents and restricted cash, beginning of period		$ 7,772	22,811		$ 4,244	7,772	4,244	$ 4,244
Cash, cash equivalents and restricted cash, end of period	$ 45,459		$ 7,772	$ 22,811		45,459	22,811	$ 7,772
Supplemental disclosure of cash flow information:
Interest paid						20,708	23,531
Non-cash investing and financing transactions:
Reclassification of notes receivable to lease incentives							$ 300
Preferred return reserve related to investments in unconsolidated joint ventures (See Note 3)						2,324
Mortgage loan receivable reserve withheld at origination (See Note 2)						142
Notes receivable reserve withheld at origination (See Note 4)						$ 353