MORTGAGE LOAN RECEIVABLES (Details) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2015 USD ($) loan	Dec. 31, 2014 USD ($) loan
Mortgage Loans on Real Estate [Line Items]
Loans receivable with fixed rates of interest	$ 347,100	$ 231,900
Percentage of loans receivable with fixed rates of interest	19.30%	15.20%
Unamortized discounts included in mortgage loan receivables held for investment, at amortized cost	$ 4,100	$ 4,200
Number of mortgage loans impaired \| loan	0	0
Carrying value, net	$ 2,128,343	$ 1,939,008
Mortgage loan receivables held for investment, at amortized cost
Mortgage Loans on Real Estate [Line Items]
Loans receivable with fixed rates of interest	$ 1,500,000	$ 1,300,000
Percentage of loans receivable with fixed rates of interest	80.70%	84.80%
Carrying value, net	$ 1,794,812	$ 1,521,053
Loan on non-accrual status
Mortgage Loans on Real Estate [Line Items]
Unamortized discounts included in mortgage loan receivables held for investment, at amortized cost	$ 2,200	$ 2,200
Number of loans on non-accrual status \| loan	1	1
Carrying value, net	$ 5,900	$ 5,900
Mortgage loan receivables held for sale
Mortgage Loans on Real Estate [Line Items]
Loans receivable with fixed rates of interest	$ 333,500	$ 418,000
Percentage of loans receivable with fixed rates of interest	100.00%	100.00%
Carrying value, net	$ 333,531	$ 417,955

Loans Receivable with Fixed Rates of Interest, Percentage

No definition available.

Name:	ladr_LoansReceivablewithFixedRatesofInterestPercentage
Namespace Prefix:	ladr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the number of mortgage loans individually impaired.

+ References

No definition available.

+ Details

Name:	ladr_NumberOfMortgageLoansIndividuallyImpaired
Namespace Prefix:	ladr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of loan with fixed rate of interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansReceivableWithFixedRatesOfInterest1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(c))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Indicates the number of mortgages under each classification.

+ 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 210.12-29.3)

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

- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

+ Details

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

- Details

Name:	us-gaap_MortgageLoansOnRealEstateLoanTypeAxis=ladr_MortgageLoanReceivablesHeldForInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateLoanTypeAxis=ladr_NonPerformingLoansHeldForInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateLoanTypeAxis=ladr_MortgageLoanReceivablesHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: