The cash outflow of amount used for repaying the outstanding principal amount of debt.

No definition available.

Name:	abr_RepaymentAmountOfOutstandingPrincipalAmountOfDebt
Namespace Prefix:	abr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 3: 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 https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: 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 https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

+ Details

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ 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:	dtr-types: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

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28555-108399

+ Details

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

- Definition

The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3255-108585

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotesOne5.00Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotesDueIn2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotes5.00Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotes8.00Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotes4.50Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotes4.50PercentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotesDueInOctober2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotes8.50Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotesDueInApril2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=abr_SeniorUnsecuredNotesDueInMay2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt Obligations - Senior Unsecured Notes, Summary (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Oct. 31, 2022	Oct. 31, 2019	Dec. 31, 2022	Dec. 31, 2021	Aug. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Obligations
Weighted average rate (as a percent)			6.54%	2.21%
Redemption of aggregate principal amount (as a percent)			100.00%
Outstanding principal balance repaid	$ 46,200
Senior Notes [Member]
Debt Obligations
Debt, Face Value (UPB)			$ 1,399,600	$ 1,295,750
Carrying value			$ 1,385,994	$ 1,280,545
Weighted average rate (as a percent)			5.40%	5.05%
Deferred financing fees			$ 13,600	$ 15,200
5.00% Convertible notes
Debt Obligations
Debt, Face Value (UPB)	$ 150,000		180,000	180,000
Carrying value			$ 177,450	$ 177,105
Weighted average rate (as a percent)			5.00%	5.00%
Interest rate (as a percent)	8.50%		5.00%	5.00%
7.375% Convertible Notes
Debt Obligations
Interest rate (as a percent)								7.375%
5.00% Convertible Notes
Debt Obligations
Debt, Face Value (UPB)			$ 175,000	$ 175,000
Carrying value			$ 172,917	$ 172,302
Weighted average rate (as a percent)			5.00%	5.00%
Interest rate (as a percent)			5.00%	5.00%
8.00% Convertible Notes
Debt Obligations
Debt, Face Value (UPB)			$ 70,750	$ 70,750		$ 70,800
Carrying value			$ 70,613	$ 70,202
Weighted average rate (as a percent)			8.00%	8.00%
Interest rate (as a percent)			8.00%			8.00%
4.50% Convertible Notes
Debt Obligations
Debt, Face Value (UPB)			$ 270,000	$ 270,000	$ 270,000	$ 275,000
Carrying value			$ 266,926	$ 266,090
Weighted average rate (as a percent)			4.50%	4.50%
Interest rate (as a percent)			4.50%		4.50%	4.50%
4.50% Senior Unsecured Notes
Debt Obligations
Debt, Face Value (UPB)			$ 275,000	$ 275,000
Carrying value			$ 272,960	$ 272,477
Weighted average rate (as a percent)			4.50%	4.50%
Interest rate (as a percent)			4.50%
4.75% Notes
Debt Obligations
Debt, Face Value (UPB)			$ 110,000	$ 110,000
Carrying value			$ 109,369	$ 109,018
Weighted average rate (as a percent)			4.75%	4.75%
Interest rate (as a percent)			4.75%
Redemption of aggregate principal amount (as a percent)		100.00%	100.00%
8.50% Notes
Debt Obligations
Debt, Face Value (UPB)			$ 150,000
Carrying value			$ 147,519
Weighted average rate (as a percent)			8.50%
Interest rate (as a percent)			8.50%
5.75% Convertible Notes
Debt Obligations
Debt, Face Value (UPB)			$ 90,000	$ 90,000			$ 90,000
Carrying value			$ 89,514	$ 89,135
Weighted average rate (as a percent)			5.75%	5.75%
Interest rate (as a percent)			5.75%				5.75%
5.625% Notes
Debt Obligations
Debt, Face Value (UPB)			$ 78,850	$ 125,000				$ 125,000
Carrying value			$ 78,726	$ 124,216
Weighted average rate (as a percent)			5.63%	5.63%
Interest rate (as a percent)	5.625%		5.625%					5.625%
Proceeds from issuance of unsecured notes	$ 47,500