Amount of the contractual principal due as of the balance sheet date of the mortgage loan (face amount).

No definition available.

Name:	ladr_MortgageLoansOnRealEstateFaceAmountOfMortgagesBalanceSheetDate
Namespace Prefix:	ladr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The reserve to cover probable credit losses related to specifically identified fixed maturity real estate loans as well as probable credit losses inherent in the remainder of that loan portfolio.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6873192&loc=d3e21338-158488

+ Details

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

- Definition

Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: 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

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5066-111524

+ Details

Name:	us-gaap_LoansReceivableCommercialRealEstate
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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_MortgageLoansOnRealEstateLoanTypeAxis=ladr_FirstMortgageHeldForSaleMember
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:

MORTGAGE LOAN RECEIVABLES - Mortgage Loan Receivables by Loan Type (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Mortgage Loans on Real Estate [Line Items]
Outstanding Face Amount	$ 2,837,900	$ 2,371,827
Provision for loan losses	(4,000)	(4,000)	$ (3,850)	$ (3,700)
Carrying Value	2,816,675	2,353,977
First mortgage loan, held for investment
Mortgage Loans on Real Estate [Line Items]
Outstanding Face Amount	2,149,727	1,843,006
Carrying Value, Gross	2,137,383	1,832,626
Mezzanine loan, held for investment
Mortgage Loans on Real Estate [Line Items]
Outstanding Face Amount	167,494	168,303
Carrying Value, Gross	166,710	167,469
Mortgage loan receivables held for investment, at amortized cost
Mortgage Loans on Real Estate [Line Items]
Outstanding Face Amount	2,317,221	2,011,309
Carrying Value, Gross	2,304,093	2,000,095
Provision for loan losses	(4,000)	(4,000)
Carrying Value	2,300,093	1,996,095
First mortgage loan, held for sale
Mortgage Loans on Real Estate [Line Items]
Outstanding Face Amount	520,679	360,518
Carrying Value	516,582	357,882
Mortgage loan receivables held for sale
Mortgage Loans on Real Estate [Line Items]
Outstanding Face Amount	520,679	360,518
Carrying Value	$ 516,582	$ 357,882