Represents the obligation remaining to be funded under commitments of the entity.

No definition available.

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Namespace Prefix:	ladr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the total commitment amount to purchase loan securities.

+ References

No definition available.

+ Details

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Namespace Prefix:	ladr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the fixed price under commitments of the entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	ladr_
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Period Type:	instant

- Definition

Represents the funded obligation under commitments of the entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	ladr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the number of extension options available under operating lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	ladr_
Data Type:	xbrli:integerItemType
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- Definition

Represents the period over which commitment is made by the entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	ladr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of arrangements with third parties, including, but not limited to, operating lease arrangement and arrangement in which the entity has agreed to expend funds to procure goods or services, or has agreed to commit resources to supply goods or services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(25))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value of financial assets, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

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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

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

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

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

- Details

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Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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

- Details

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Data Type:	na
Balance Type:
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- Details

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COMMITMENTS AND CONTINGENCIES - Additional Information (Details)	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($)	Dec. 31, 2012 Extension_Option	Dec. 31, 2011 Extension_Option
Unfunded Loan Commitments
Number of extension options \| Extension_Option				0	0
Rent expense	$ 1,200,000	$ 1,500,000	$ 1,800,000
Mortgage loan receivables held for investment, at amortized cost
Unfunded Loan Commitments
Unfunded commitments of mortgage loan receivables held for investment	147,700,000	112,800,000
First mortgage loan financing
Unfunded Loan Commitments
Unfunded commitments of mortgage loan receivables held for investment	146,300,000	111,400,000
Mezzanine loan
Unfunded Loan Commitments
Unfunded commitments of mortgage loan receivables held for investment	1,400,000	1,400,000
Commitment to purchase GN construction loan securities
Unfunded Loan Commitments
Commitment to purchase loan securities	$ 0	28,800,000
Funded		26,700,000
Remaining to be funded		2,100,000
Fair value of commitments		$ 54,273
Commitment to purchase GN construction loan securities \| Minimum
Unfunded Loan Commitments
Period over which commitment is made to purchase loan securities	6 months
Fixed prices (in dollars per unit) \| $ / shares		$ 102.0
Commitment to purchase GN construction loan securities \| Maximum
Unfunded Loan Commitments
Period over which commitment is made to purchase loan securities	12 months