Debt instrument, default interest.

No definition available.

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

- Definition

Decrease in future availability of mortgage loan.

+ References

No definition available.

+ Details

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Namespace Prefix:	akr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Increase (decrease) in mortgage loans.

+ References

No definition available.

+ Details

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Namespace Prefix:	akr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Mortgage debt, interest owner percentage in property.

+ References

No definition available.

+ Details

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

- Definition

Number of properties collateralized.

+ References

No definition available.

+ Details

Name:	akr_NumberOfPropertiesCollateralized
Namespace Prefix:	akr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Prepayment of line of credit.

+ References

No definition available.

+ Details

Name:	akr_PrepaymentOfLineOfCredit
Namespace Prefix:	akr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of mortgage loans within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Footnote 3
-Subsection 29

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Footnote 3))
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

+ Details

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Namespace Prefix:	srt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of outstanding long-term debt or borrowing associated with any securities or credit agreement for which there has been a default in principal, interest, sinking fund, or redemption provisions, or any breach of covenant that existed at the end of the period and subsequently has not been cured.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(c))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_DebtDefaultLongtermDebtAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

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

- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

No definition available.

+ Details

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

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585

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-Name Accounting Standards Codification
-Topic 235
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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

- Details

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- Details

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Debt - Mortgage Payable - Additional Information (Details)	6 Months Ended
	Jun. 30, 2019 USD ($) property loan	Dec. 31, 2018 USD ($) property
Debt Instrument [Line Items]
Unsecured line of credit	$ 39,000,000
Mortgages
Debt Instrument [Line Items]
Scheduled principal payment	$ 3,200,000
Number of properties collateralized \| property	44	43
Interest Rate Swaps
Debt Instrument [Line Items]
Derivative, notional amount	$ 156,000,000.0
Derivative weighted average interest rate	2.43%
Interest Rate Swaps \| Mortgages
Debt Instrument [Line Items]
Derivative, notional amount	$ 91,500,000
Derivative weighted average interest rate	2.74%
Fund Portfolio \| Mortgages
Debt Instrument [Line Items]
Number of mortgage loans \| loan	4
Borrowings, amount	$ 118,300,000
Fund IV \| Mortgages
Debt Instrument [Line Items]
Borrowings, amount	23,800,000
Unsecured line of credit	18,900,000
Repayments of debt	38,200,000
Decrease in future availability of mortgage loan	3,900,000
Fund IV \| BSP I \| Mortgages
Debt Instrument [Line Items]
Increase (decrease) in mortgage loans	9,400,000
Fund IV \| 717 North Michigan Avenue \| Mortgages
Debt Instrument [Line Items]
Increase (decrease) in mortgage loans	(9,900,000)
Fund III \| Mortgages
Debt Instrument [Line Items]
Repayments of debt	4,700,000
Fund III \| Construction Loans
Debt Instrument [Line Items]
Unsecured line of credit	5,900,000
Core Portfolio
Debt Instrument [Line Items]
Derivative, notional amount	587,574,000
Core Portfolio \| Mortgages
Debt Instrument [Line Items]
Prepayment of line of credit	49,000,000.0
Core Portfolio \| Mortgages \| Brandywine Portfolio
Debt Instrument [Line Items]
Debt default, amount	$ 26,300,000	$ 26,300,000
Interest rate, stated percentage	6.00%
Debt default interest	5.00%
Interest owner percentage in property	22.00%
LIBOR \| Mortgages
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
LIBOR \| Fund Portfolio \| Mortgages
Debt Instrument [Line Items]
Basis spread on variable rate	1.64%
LIBOR \| Fund IV \| Mortgages
Debt Instrument [Line Items]
Basis spread on variable rate	2.35%
LIBOR \| Fund IV \| Variable Rate Debt \| Mortgages
Debt Instrument [Line Items]
Basis spread on variable rate	3.10%
LIBOR \| Fund III \| Mortgages
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%