Summary of Significant Accounting Policies - Real Estate Properties (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
Land	$ 627	$ 313
Building	652	1,019
Lease intangibles - asset	91	132
Lease intangibles - (liability)		(285)
Real Estate Held-for-sale, gross	1,370	1,179
Accumulated depreciation and amortization, net	(125)	20
Total Real Estate Held for Sale, net	$ 1,245	$ 1,199

The cumulative amount of depreciation for real estate property held for sale.

No definition available.

Name:	adc_RealEstateHeldForSaleAccumulatedDepreciation
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Gross amount as of investments in buildings held for sale, excluding real estate considered to be inventory of the entity.

+ References

No definition available.

+ Details

Name:	adc_RealEstateHeldForSaleBuilding
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gross amount as of investments in land, buildings and lease intangibles held for sale, excluding real estate considered to be inventory of the entity.

+ References

No definition available.

+ Details

Name:	adc_RealEstateHeldForSaleGross
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gross amount as of investments in land held for sale, excluding real estate considered to be inventory of the entity.

+ References

No definition available.

+ Details

Name:	adc_RealEstateHeldForSaleLand
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gross amount as of investments in lease intangibles held for sale, excluding real estate considered to be inventory of the entity.

+ References

No definition available.

+ Details

Name:	adc_RealEstateHeldForSaleLeaseIntangibles
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gross amount as of investments in lease liabilities held for sale, excluding real estate considered to be inventory of the entity.

+ References

No definition available.

+ Details

Name:	adc_RealEstateHeldForSaleLeaseLiability
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of real estate investments, net of accumulated depreciation .

+ References

No definition available.

+ Details

Name:	adc_RealEstateHeldForSaleNetTotal
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_AccountingPoliciesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration