Equity Method Investment, Sale of Ownership Percentage

No definition available.

Name:	ari_EquityMethodInvestmentSaleofOwnershipPercentage
Namespace Prefix:	ari_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Mortgage Loan, Extension Term

+ References

No definition available.

+ Details

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

- Definition

Other Commitment, Commitment Transfer

+ References

No definition available.

+ Details

Name:	ari_OtherCommitmentCommitmentTransfer
Namespace Prefix:	ari_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Ownership Percentage by Parent and Related Parties

+ References

No definition available.

+ Details

Name:	ari_OwnershipPercentagebyParentandRelatedParties
Namespace Prefix:	ari_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Proceeds from Agreement Fee

+ References

No definition available.

+ Details

Name:	ari_ProceedsfromAgreementFee
Namespace Prefix:	ari_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Related Party Transaction, Annual Management Fee, Rate

+ References

No definition available.

+ Details

Name:	ari_RelatedPartyTransactionAnnualManagementFeeRate
Namespace Prefix:	ari_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Related Party Transaction, Extension Period

+ References

No definition available.

+ Details

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

- Definition

Related Party Transaction, Termination Fee Calculation Period

+ References

No definition available.

+ Details

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

- Definition

Related Party Transaction, Termination Vote Threshold Rate, Percentage

+ References

No definition available.

+ Details

Name:	ari_RelatedPartyTransactionTerminationVoteThresholdRatePercentage
Namespace Prefix:	ari_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Related Party Transaction, Voting Requirement to Termination Management Agreement, Percentage

+ References

No definition available.

+ Details

Name:	ari_RelatedPartyTransactionVotingRequirementtoTerminationManagementAgreementPercentage
Namespace Prefix:	ari_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Related party Transaction, Termination Notice Period

+ References

No definition available.

+ Details

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

- Definition

Carrying amount as of the balance sheet date of obligations due all related parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k)(1))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15(3),(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.17)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- 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 the contractual principal due at the origination of the mortgage loan (face amount).

+ References

Reference 1: 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

Reference 2: 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

+ Details

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

- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow for cost incurred directly with the issuance of an equity security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585

+ Details

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

- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ 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 (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

+ Details

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

- Definition

The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

+ Details

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

- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

+ Details

Name:	us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_LimitedLiabilityCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=ari_ManagementFeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=ari_ReimbursementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	dei_LegalEntityAxis=us-gaap_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	dei_LegalEntityAxis=ari_ChampLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_OtherCommitmentsAxis=ari_CommitmenttoInvestinKBCDMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=ari_UnfundedCommitmentChampL.P.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesBPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_PrivatePlacementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=ari_ChampLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=ari_AdditionalInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_FirstMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=ari_CommitmenttoPurchaseLoanPortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ari_CommercialMortgagePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=ari_LuxuryCondominiumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=ari_PariPassuInterestsinPreDevelopmentMezzanineLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Related Party Transactions (Details) € in Thousands, $ in Thousands			1 Months Ended					3 Months Ended								12 Months Ended
	Oct. 05, 2016 USD ($)	Sep. 21, 2015 USD ($)	Jun. 30, 2016 EUR (€)	Feb. 28, 2015 USD ($)	Feb. 28, 2015 EUR (€)	Sep. 30, 2014 USD ($)	Sep. 30, 2014 EUR (€)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 EUR (€)	Oct. 05, 2016 GBP (£)	Sep. 30, 2016 EUR (€)	Jun. 30, 2016 EUR (€)	Sep. 29, 2015 USD ($)	Jan. 31, 2015 USD ($)	Jan. 31, 2015 EUR (€)	Sep. 30, 2014 EUR (€)	Sep. 30, 2013 USD ($)	Sep. 30, 2013 EUR (€)
Related Party Transaction [Line Items]
Related party expenses								$ 7,015	$ 5,903	$ 5,242	$ 5,229	$ 5,294	$ 4,097	$ 3,887	$ 3,341	$ 23,388	$ 16,619	$ 11,960
Base management fees incurred but not yet paid								7,015				5,297				7,015	5,297
Placement agent fees paid																406	987	389
Initial funding for equity method investment																$ 362	3,929	39,477
Limited Liability Company [Member]
Related Party Transaction [Line Items]
Rate of management fees																1.50%
Extension period																1 year
Voting requirement to termination management agreement, percentage																66.66%
Period of termination																180 days
Termination vote threshold rate, percentage																300.00%
Termination fee calculation period																24 months
Limited Liability Company [Member] \| Management Fees [Member]
Related Party Transaction [Line Items]
Related party expenses																$ 23,388	16,619	11,960
Base management fees incurred but not yet paid								$ 7,015				5,297				7,015	5,297
Limited Liability Company [Member] \| Reimbursements [Member]
Related Party Transaction [Line Items]
Related party expenses																$ 2,526	$ 1,421	$ 985
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Agreement fee payment proceeds												$ 750
Champ Limited Partnership [Member] \| Subsidiaries [Member]
Related Party Transaction [Line Items]
Indirect ownership interest from limited partnership						59.00%																				59.00%
KBC Bank Deutschland AG [Member] \| Champ LP [Member]
Related Party Transaction [Line Items]
Indirect ownership interest from limited partnership						35.00%																				35.00%
Company and affiliated investors ownership, percentage									100.00%												100.00%
KBCD Partnership [Member]
Related Party Transaction [Line Items]
Indirect ownership interest from limited partnership																											21.00%	21.00%
Initial funding for equity method investment						$ 39,477	€ 30,724
BKB Bank [Member]
Related Party Transaction [Line Items]
Indirect ownership interest from limited partnership								9.34%								9.34%			9.34%
Company and affiliated investors ownership, percentage								100.00%	100.00%							100.00%			100.00%		100.00%
Commitment to Invest in KBCD [Member]
Related Party Transaction [Line Items]
Commitment to invest						$ 50,000																				€ 38,000	$ 50,000	€ 38,000
Unfunded Commitment, Champ L.P. [Member]
Related Party Transaction [Line Items]
Commitment to invest								$ 2,947	$ 2,947	$ 2,947						$ 2,947			€ 2,802		€ 2,802	€ 2,802
Other commitment, commitment transfer \| €			€ 427
Series B Preferred Stock [Member] \| Private Placement [Member]
Related Party Transaction [Line Items]
Placement agent fees paid		$ 500
Champ LP [Member]
Related Party Transaction [Line Items]
Ownership interest				48.00%	48.00%
Proceeds from sale of equity method investments				$ 20,794	€ 16,314
Champ LP [Member] \| Additional Investment [Member]
Related Party Transaction [Line Items]
Commitment to invest																								$ 3,929	€ 3,331
First Mortgage [Member] \| Commitment to Purchase Loan Portfolio [Member]
Related Party Transaction [Line Items]
Commitment to invest																							$ 375,355
Commercial Mortgage Portfolio Segment [Member]
Related Party Transaction [Line Items]
Mortgage loan, extension term	12 months
Commercial Mortgage Portfolio Segment [Member] \| Luxury Condominium [Member]
Related Party Transaction [Line Items]
Original face amount	$ 123,400																			£ 100,000,000
Commercial Mortgage Portfolio Segment [Member] \| Luxury Condominium [Member] \| Pari Passu Interests in Pre-Development Mezzanine Loan [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Original face amount	$ 57,400																			£ 45,000,000