Segments - Reconciliation of Net Operating Income to Net Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gross profit	$ 30,898		$ 29,429		$ 61,789	$ 59,728
Amortization of finance leases	(278)		(146)		(467)	(293)
General and administrative expenses	(3,487)		(2,988)		(7,508)	(6,781)
Acquisition, development and other pursuit costs	(32)		(502)		(103)	(529)
Impairment charges	(83)		0		(3,122)	(158)
Gain on real estate dispositions	0		2,776		3,717	2,776
Interest income	6,746		4,412		10,862	11,638
Interest expense	(8,418)		(7,227)		(16,393)	(15,415)
Change in fair value of derivatives and other	314		(6)		707	(1,742)
Unrealized credit loss release (provision)	(388)		117		(333)	(260)
Other income (expense), net	7		286		186	344
Income tax benefit (provision)	461		(65)		480	192
Net income	8,455	$ 6,009	12,309	$ 9,135	14,464	21,444
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gross profit	30,898		29,429		61,789	59,728
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization	(17,285)		(13,777)		(35,351)	(28,056)
Amortization of finance leases	(278)		(146)		(467)	(293)
General and administrative expenses	(3,487)		(2,988)		(7,508)	(6,781)
Acquisition, development and other pursuit costs	(32)		(502)		(103)	(529)
Impairment charges	(83)		0		(3,122)	(158)
Gain on real estate dispositions	0		2,776		3,717	2,776
Interest income	6,746		4,412		10,862	11,638
Interest expense	(8,418)		(7,227)		(16,393)	(15,415)
Change in fair value of derivatives and other	314		(6)		707	(1,742)
Unrealized credit loss release (provision)	(388)		117		(333)	(260)
Other income (expense), net	7		286		186	344
Income tax benefit (provision)	$ 461		$ (65)		$ 480	$ 192