Real Estate Investments (Details Textual) $ in Thousands, ft² in Millions	3 Months Ended
Mar. 31, 2018 USD ($) ft²	Dec. 31, 2017 USD ($) ft²
Real Estate Properties [Line Items]
Proceeds from Sale of Real Estate	$ 20,000
Number of Real Estate Properties	463	436
Land Subject to Ground Leases \| ft²	8.9	8.7
Real Estate Investment Property, Net, Total	$ 1,271,569	$ 1,214,016
Options Exercised [Member]
Real Estate Properties [Line Items]
Proceeds from Sale of Real Estate	3,900
Gains (Losses) on Sales of Investment Real Estate	1,000
Five Development And PCS Projects [Member]
Real Estate Properties [Line Items]
Property Subject to or Available for Operating Lease, Gross	24,100
Nine Development And PCS Projects [Member]
Real Estate Properties [Line Items]
Property Subject to or Available for Operating Lease, Gross	50,800
Five Real Estate Properties [Member]
Real Estate Properties [Line Items]
Proceeds from Sale of Real Estate	16,100
Gains (Losses) on Sales of Investment Real Estate	3,600
Seventy Nine Retail Net Lease Assets [Member]
Real Estate Properties [Line Items]
Payments to Acquire Property, Plant, and Equipment	$ 98,800
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (in year)	13 years 7 months 6 days
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land	$ 25,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings	52,800
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 20,600

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

+ Details

Name:	us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of facility held for productive use including, but not limited to, office, production, storage and distribution facilities, acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472

+ Details

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

- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

+ Details

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

- Definition

Amount of real estate acquired, at the acquisition date.

+ References

+ Details

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

- Definition

The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.14(d))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

Name:	us-gaap_GainsLossesOnSalesOfInvestmentRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Area of land subject to a ground lease.

+ References

No definition available.

+ Details

Name:	us-gaap_LandSubjectToGroundLeases
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Cash received for the sale of real estate that is not part of an investing activity during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount before accumulated depreciation of physical assets used in the normal conduct of business to produce goods and services subject to or available for lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=77907726&loc=d3e41457-112716

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84164653&loc=d3e41551-112718

+ Details

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

- Definition

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(d))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_OptionIndexedToIssuersEquityEquityAxis=adc_OptionsExercisedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	adc_NumberOfProjectsAxis=adc_FiveDevelopmentAndPcsProjectsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	adc_NumberOfProjectsAxis=adc_NineDevelopmentAndPcsProjectsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	adc_NumberOfProjectsAxis=adc_FiveRealEstatePropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=adc_SeventyNineRetailNetLeaseAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: