Intangible Assets and Liabilities - Scheduled Annual Net Amortization (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Scheduled Annual Net Amortization of Intangibles
2022	$ 13,812
2023	11,522
2024	9,010
2025	8,193
2026	6,907
Thereafter	26,805
Total	76,249
Net (Increase) Decrease in Rental Income
Scheduled Annual Net Amortization of Intangibles
2022	391
2023	489
2024	529
2025	548
2026	206
Thereafter	(477)
Total	1,686
Increase to Amortization
Scheduled Annual Net Amortization of Intangibles
2022	14,203
2023	12,011
2024	9,539
2025	8,741
2026	7,113
Thereafter	26,328
Total	$ 77,935

Finite-Lived Intangible Assets Liabilities, Future Amortization Expense

No definition available.

Name:	cpa18_FiniteLivedIntangibleAssetsLiabilitiesFutureAmortizationExpenseAbstract
Namespace Prefix:	cpa18_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount after amortization of assets and liabilities, excluding financial assets and liabilities, lacking physical substance with a finite life.

+ References

No definition available.

+ Details

Name:	cpa18_FiniteLivedIntangibleAssetsLiabilitiesNet
Namespace Prefix:	cpa18_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization for asset, excluding financial asset and goodwill, lacking physical substance with finite life expected to be recognized after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	cpa18_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseAxis=cpa18_NetChangeInRentalIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	cpa18_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseAxis=cpa18_IncreasetoAmortizationPropertyExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: