Investments in Real Estate and Real Estate Under Construction - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended	0 Months Ended
Dec. 31, 2014 Property	Dec. 31, 2013	Sep. 01, 2012
Investments in Real Estate and Real Estate Under Construction [Line Items]
Below-market leases, net of accretion	$ 54,414lxp_BelowMarketLeasesNetOfAccretion	$ 59,781lxp_BelowMarketLeasesNetOfAccretion
Future accretion, year 1	4,383lxp_FutureAccretionYearOne
Future accretion, year 2	3,312lxp_FutureAccretionYearTwo
Future accretion, year 3	2,918lxp_FutureAccretionYearThree
Future accretion, year 4	2,911lxp_FutureAccretionYearFour
Future accretion, year 5	2,603lxp_FutureAccretionYearFive
Acquisition related costs	1,901	1,349
Investments in real estate under construction	106,238us-gaap_ConstructionInProgressGross	74,350us-gaap_ConstructionInProgressGross
Number of real estate properties	215us-gaap_NumberOfRealEstateProperties
Net Lease Strategic Assets Fund L P [Member]
Investments in Real Estate and Real Estate Under Construction [Line Items]
Payments to acquire businesses, gross			9,438
Equity interest in acquiree, remeasurement gain			167,864
Development Deals [Member]
Investments in Real Estate and Real Estate Under Construction [Line Items]
Capitalized interest	$ 2,828	$ 1,472

Below-market Leases, Net of Accretion

No definition available.

Name:	lxp_BelowMarketLeasesNetOfAccretion
Namespace Prefix:	lxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Future Accretion, Year Five

+ References

No definition available.

+ Details

Name:	lxp_FutureAccretionYearFive
Namespace Prefix:	lxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Future Accretion, Year Four

+ References

No definition available.

+ Details

Name:	lxp_FutureAccretionYearFour
Namespace Prefix:	lxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Future Accretion, Year One

+ References

No definition available.

+ Details

Name:	lxp_FutureAccretionYearOne
Namespace Prefix:	lxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Future Accretion, Year Three

+ References

No definition available.

+ Details

Name:	lxp_FutureAccretionYearThree
Namespace Prefix:	lxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Future Accretion, Year Two

+ References

No definition available.

+ Details

Name:	lxp_FutureAccretionYearTwo
Namespace Prefix:	lxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	lxp_InvestmentsInRealEstateAndRealEstateUnderConstructionLineItems
Namespace Prefix:	lxp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of accumulated interest costs capitalized as part of property, plant and equipment cost basis.

+ References

No definition available.

+ Details

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

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 23

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e1043-128460

+ Details

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

- Definition

In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)(2)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

+ Details

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

- Definition

Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

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

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ 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 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=lxp_NetLeaseStrategicAssetsFundLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=lxp_DevelopmentDealsMember
Namespace Prefix:
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Period Type: