Segment Reporting - Segment Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information, Profit (Loss)
Revenues	$ 204,217	$ 177,067	$ 197,439
Operating expenses	(165,085)	(127,261)	(132,509)
Interest expense	(50,959)	(43,343)	(48,019)
Gain on sale of real estate, net	44,015	2,390	24,773
Other gains and (losses)	(2,728)	14,217	2,530
(Provision for) benefit from income taxes	(1,850)	(769)	(210)
Net loss (income) attributable to noncontrolling interests	236	(9,958)	(11,432)
Net Income Attributable to CPA:18 – Global	27,846	12,343	32,572
Operating Segments | Net Lease
Segment Reporting Information, Profit (Loss)
Revenues	122,036	104,611	122,038
Operating expenses	(97,628)	(63,583)	(69,959)
Interest expense	(35,604)	(28,388)	(34,105)
Gain on sale of real estate, net	1,245	2,390	9,932
Other gains and (losses)	387	(3,231)	1,203
(Provision for) benefit from income taxes	(539)	52	1,019
Net loss (income) attributable to noncontrolling interests	10,773	(2,868)	(759)
Net Income Attributable to CPA:18 – Global	670	8,983	29,369
Operating Segments | Self Storage
Segment Reporting Information, Profit (Loss)
Revenues	71,613	61,426	60,767
Operating expenses	(37,129)	(36,407)	(35,604)
Interest expense	(11,833)	(13,447)	(13,802)
Other gains and (losses)	(353)	12,329	(942)
(Provision for) benefit from income taxes	(160)	(110)	(115)
Net Income Attributable to CPA:18 – Global	22,138	23,791	10,304
Operating Segments | Other Operating Properties
Segment Reporting Information, Profit (Loss)
Revenues	10,568	9,604	10,550
Operating expenses	(9,609)	(7,749)	(7,713)
Interest expense	(3,402)	(1,424)	133
Gain on sale of real estate, net	42,770	0	14,841
Other gains and (losses)	(1,513)	19	(182)
(Provision for) benefit from income taxes	(104)	241	87
Net loss (income) attributable to noncontrolling interests	(3,192)	135	(2,541)
Net Income Attributable to CPA:18 – Global	35,518	826	15,175
Corporate
Segment Reporting Information, Profit (Loss)
Net loss (income) attributable to noncontrolling interests	(7,345)	(7,225)	(8,132)
Unallocated Corporate Overhead	(23,121)	(15,473)	(18,220)
All Other
Segment Reporting Information, Profit (Loss)
Revenues	0	1,426	4,076
Operating expenses	(14)	(45)	0
Other gains and (losses)	0	60	0
Net Income Attributable to CPA:18 – Global	$ (14)	$ 1,441	$ 4,076