Secured Debt Arrangements, Net - Additional Information (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2023 USD ($) facility	Jun. 30, 2023 USD ($) facility	Dec. 31, 2022
Line of Credit Facility [Line Items]
Number of credit facilities \| facility	3	3
Weighted average haircut under repurchase agreements	30.70%	30.70%	31.21%
Debt instrument, covenant, interest coverage ratio, minimum	150.00%	150.00%
Maximum interest coverage ratio	375.00%	375.00%
Barclays Securitization \| Line of Credit \| VIE
Line of Credit Facility [Line Items]
Deferring or waiving debt service payments, term		18 months
2022 New Credit Facilities \| Line of Credit
Line of Credit Facility [Line Items]
Maximum amount of borrowings	$ 600,000,000	$ 600,000,000
Two Existing Credit Facilities \| Line of Credit
Line of Credit Facility [Line Items]
Line of credit facility, increase (decrease), net		$ 83,300,000
Revolving Credit Facility \| 2023 Revolving Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Recourse, percentage	5.00%	5.00%
Minimum unrestricted cash	$ 30,000,000	$ 30,000,000
Debt instrument, covenant, interest coverage ratio, maximum amount two	400.00%	400.00%
Net cash proceeds of additional equity issuances, amount	$ 1,250,000,000	$ 1,250,000,000
Tangible net worth, percentage	75.00%	75.00%
Debt instrument, covenant, interest coverage ratio, minimum	150.00%	150.00%
Revolving Credit Facility \| 2023 Revolving Credit Facility \| Bank of America, N.A. \| Line of Credit
Line of Credit Facility [Line Items]
Maximum amount of borrowings	$ 170,000,000	$ 170,000,000
Maturity term	3 years
Line of Credit Facility, Qualifying Commercial Loan Borrowings, Term	2 years
Line of Credit Facility, Real Property Owned Asset Borrowings, Term	6 months
Line of credit facility, commitment fee amount	$ 85,900	$ 113,300

Debt Instrument, Covenant, Indebtedness to Tangible Worth Ratio, Maximum, Amount

No definition available.

Name:	ari_DebtInstrumentCovenantIndebtednessToTangibleWorthRatioMaximumAmount
Namespace Prefix:	ari_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Interest Coverage Ratio, Maximum

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentCovenantInterestCoverageRatioMaximum
Namespace Prefix:	ari_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Interest Coverage Ratio, Minimum

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentCovenantInterestCoverageRatioMinimum
Namespace Prefix:	ari_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Liquidity Ratio Required, Minimum

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentCovenantLiquidityRatioRequiredMinimum
Namespace Prefix:	ari_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Liquidity Required, Minimum, Amount

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentCovenantLiquidityRequiredMinimumAmount
Namespace Prefix:	ari_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Instrument, Covenant, Net Cash Proceeds Of Additional Equity Issuances, Amount

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentCovenantNetCashProceedsOfAdditionalEquityIssuancesAmount
Namespace Prefix:	ari_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Instrument, Covenant, Tangible Net Worth, Percentage

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentCovenantTangibleNetWorthPercentage
Namespace Prefix:	ari_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Waiving Of Debt Service Payments, Term

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentWaivingOfDebtServicePaymentsTerm
Namespace Prefix:	ari_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Weighted Average Haircut Under Repurchase Agreements

+ References

No definition available.

+ Details

Name:	ari_DebtInstrumentWeightedAverageHaircutUnderRepurchaseAgreements
Namespace Prefix:	ari_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Qualifying Commercial Loan Borrowings, Term

+ References

No definition available.

+ Details

Name:	ari_LineOfCreditFacilityQualifyingCommercialLoanBorrowingsTerm
Namespace Prefix:	ari_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Real Property Owned Asset Borrowings, Term

+ References

No definition available.

+ Details

Name:	ari_LineOfCreditFacilityRealPropertyOwnedAssetBorrowingsTerm
Namespace Prefix:	ari_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Credit Facilities

+ References

No definition available.

+ Details

Name:	ari_NumberOfCreditFacilities
Namespace Prefix:	ari_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the fee for available but unused credit capacity under the credit facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

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

- Definition

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

Amount of increase (decrease) of the credit facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityIncreaseDecreaseForPeriodNet
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

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=ari_BarclaysSecuritizationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ari_A2022NewCreditFacilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ari_A2023RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=ari_BankOfAmericaNAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: