Estimated Amortization of Lease Intangible Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Schedule of Estimated Amortization Expense for Intangible Assets and Unfavorable Lease Liability [Line Items]
2013	$ 2,625
2014	3,130
2015	2,600
2016	2,266
2017	2,143
Thereafter	12,556
Total	$ 25,320	$ 26,455

Future amortization expense of lease intangible liabilities, after year five.

No definition available.

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Namespace Prefix:	exl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Future amortization expense of lease intangible liabilities, remainder of fiscal year.

+ References

No definition available.

+ Details

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Namespace Prefix:	exl_
Data Type:	xbrli:monetaryItemType
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- Definition

Future amortization expense of lease intangible liabilities, year five.

+ References

No definition available.

+ Details

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Namespace Prefix:	exl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Future amortization expense of lease intangible liabilities, year four.

+ References

No definition available.

+ Details

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Namespace Prefix:	exl_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Future amortization expense of lease intangible liabilities, year three.

+ References

No definition available.

+ Details

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Namespace Prefix:	exl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Future amortization expense of lease intangible liabilities, year two.

+ References

No definition available.

+ Details

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Namespace Prefix:	exl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:	exl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents a liability associated with the acquisition of an off-market lease when the terms of the lease are unfavorable to the market terms for the lease at the date of acquisition.

+ 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 210.5-02.24)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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