Equity Method Investment, Ownership Percentage by Third Party

No definition available.

Name:	akr_EquityMethodInvestmentOwnershipPercentageByThirdParty
Namespace Prefix:	akr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Equity Method Investment, Preferred Return

+ References

No definition available.

+ Details

Name:	akr_EquityMethodInvestmentPreferredReturn
Namespace Prefix:	akr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Mortgage Loans On Real Estate, Accrued Interest

+ References

No definition available.

+ Details

Name:	akr_MortgageLoansOnRealEstateAccruedInterest
Namespace Prefix:	akr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of gain (loss) on sale or disposal of an equity method investment.

+ References

No definition available.

+ Details

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

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66022249&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The carrying amount of the outstanding balance due under the mortgage loan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

+ Details

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

- Definition

The carrying amount of mortgage loans on real estate that were sold during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29.6)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

+ Details

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

- Definition

The number of businesses acquired by the entity during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfBusinessesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

+ Details

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

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

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=akr_BrandywinePortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=akr_CorePortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=akr_CrossroadsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=akr_GeorgetownPortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=akr_GothamPlazaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=akr_RenaissancePortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=akr_TownCenterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=akr_MarketSquareWilmingtonDEMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentGeographicRegionAxis=akr_AlexandriaVirginiaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentGeographicRegionAxis=akr_WashingtonD.C.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	akr_ExchangeTransactionAxis=akr_ExchangeTransactionOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	akr_ExchangeTransactionAxis=akr_ExchangeTransactionTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments in and Advances to Unconsolidated Affiliates - Core Portfolio (Details) $ in Thousands					1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 28, 2018 USD ($)	Nov. 16, 2017 USD ($)	May 01, 2017 USD ($)	Jan. 04, 2017 USD ($) ft²	Apr. 29, 2016 USD ($)	Mar. 31, 2018 USD ($) ft² property	Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items]
Purchase Price						$ 46,596	$ 254,532
Notes receivable, net						108,959	153,829
Brandywine Portfolio
Schedule of Equity Method Investments [Line Items]
Preferred return						5,600
Core Portfolio
Schedule of Equity Method Investments [Line Items]
Purchase Price						1,337	42,800
Notes receivable, net						56,475	101,695
Note receivable accrued interest						200
Equity method investments						$ 237,425	216,583
Core Portfolio \| Crossroads
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage						49.00%
Core Portfolio \| Georgetown Portfolio
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage						50.00%
Equity method investments						$ 3,540	3,479
Core Portfolio \| Gotham Plaza
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage						49.00%
Equity method investments						$ 29,408	29,416
Core Portfolio \| Renaissance Portfolio
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage						20.00%
Square footage of real estate property (in square feet) \| ft²						213,000
Percentage of voting interests acquired				20.00%
Number of businesses acquired \| property						18
Equity method investments						$ 34,294	$ 35,041
Core Portfolio \| Brandywine Portfolio
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (in square feet) \| ft²						1,000,000
Repayments of debt					$ 140,000
Note receivable exchanged	$ 22,000		$ 16,000
Notes receivable, net			153,400			$ 38,700
Note receivable accrued interest	$ 300		$ 300
Core Portfolio \| Town Center
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage		22.22%				75.22%	61.11%
Note receivable exchanged						$ 22,000
Note receivable accrued interest						$ 300
Equity method investment, ownership percentage by third party	14.11%	38.89%				24.78%
Equity method investments	$ 22,300	$ 61,600
Gain on equity method investment	$ 12,700	$ 34,500
Core Portfolio \| Market Square
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage		22.22%	61.11%
Equity method investment, ownership percentage by third party		38.89%	38.89%
Equity method investments			$ 16,300
Gain on equity method investment			$ 9,800
Core Portfolio \| Alexandria, Virginia \| Renaissance Portfolio
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (in square feet) \| ft²				6,200
Purchase Price				$ 3,000
Number of businesses acquired \| property						2
Core Portfolio \| Washington D.C. \| Renaissance Portfolio
Schedule of Equity Method Investments [Line Items]
Number of businesses acquired \| property						16
Exchange Transaction One \| Core Portfolio \| Brandywine Portfolio
Schedule of Equity Method Investments [Line Items]
Note receivable exchanged		$ 16,000
Note receivable accrued interest		600
Exchange Transaction Two \| Core Portfolio \| Brandywine Portfolio
Schedule of Equity Method Investments [Line Items]
Note receivable exchanged		60,700
Note receivable accrued interest		$ 900