Business acquisition initial purchase price adjustment.

No definition available.

Name:	exls_BusinessAcquisitionInitialPurchasePriceAdjustment
Namespace Prefix:	exls_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of restricted shares of common stock issued.

+ References

No definition available.

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate fair value amount of restricted shares of common stock.

+ References

No definition available.

+ Details

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

- Definition

Earnout payments fair value disclosure.

+ References

No definition available.

+ Details

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

- Definition

Number of consumers.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Working capital baseline and other adjustments as of the acquisition date.

+ References

No definition available.

+ Details

Name:	exls_WorkingCapitalBaselineAndOtherAdjustmentsAsOfAcquisitionDate
Namespace Prefix:	exls_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

+ Details

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

- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

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

- Definition

Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionDateOfAcquisitionAgreement1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

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

- 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

Amount of liability recognized arising from contingent consideration in a business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 35

-Paragraph 1

-Subparagraph b

-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 25

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

+ Details

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

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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=56944662&loc=d3e3213-108585

+ Details

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

- Definition

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(d))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Details

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Period Type:

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
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- Details

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- Details

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- Details

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Business Combinations, Goodwill and Intangible Assets - Additional Information (Detail) $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 20, 2015 USD ($) Customer shares	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Revenues		$ 155,621	$ 119,738	$ 299,131	$ 241,535
Amortization expense		2,808	1,489	4,867	3,025
Indefinite lived trade names and trademarks		900		900		$ 900
United States [Member]
Business Acquisition [Line Items]
Revenues		122,840	$ 87,888	$ 234,705	$ 178,301
RPM Direct LLC and RPM Data Solutions LLC [Member]
Business Acquisition [Line Items]
Business acquisition, Agreement date				Mar. 20, 2015
Business acquisition, cash consideration	$ 46,925
Working capital adjustments included in business acquisitions cash consideration	75
Adjustments to purchase price related to financial performance of the Target Companies for 2014	0
Fair value of earn-out payment	$ 2,844
Business acquisition, Number of restricted shares of common stock issued \| shares	122,131
Business acquisition, aggregate fair value amount of restricted shares of common stock	$ 4,150
Aggregate fair value of restricted stock units granted	$ 3,850
Restricted stock units granted \| shares	113,302
Number of consumers \| Customer	250,000,000
Acquisition related costs				$ 303
Revenues		$ 10,319		$ 11,511
RPM Direct LLC and RPM Data Solutions LLC [Member] \| United States [Member]
Business Acquisition [Line Items]
Number of consumers \| Customer	120,000,000
RPM Direct LLC and RPM Data Solutions LLC [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Earn out consideration payable	$ 23,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted average life of intangible assets				8 years 9 months 18 days
Customer Relationships [Member] \| RPM Direct LLC and RPM Data Solutions LLC [Member]
Business Acquisition [Line Items]
Useful life				5 years 8 months 12 days
Trade Names [Member] \| RPM Direct LLC and RPM Data Solutions LLC [Member]
Business Acquisition [Line Items]
Useful life				3 years
Developed Technology [Member]
Business Acquisition [Line Items]
Weighted average life of intangible assets				6 years 6 months
Developed Technology [Member] \| RPM Direct LLC and RPM Data Solutions LLC [Member]
Business Acquisition [Line Items]
Useful life				5 years
Non-compete Agreements [Member]
Business Acquisition [Line Items]
Weighted average life of intangible assets				4 years 6 months
Non-compete Agreements [Member] \| RPM Direct LLC and RPM Data Solutions LLC [Member]
Business Acquisition [Line Items]
Useful life				5 years
Leasehold Benefits [Member]
Business Acquisition [Line Items]
Weighted average life of intangible assets				8 years
Trade Names and Trademarks [Member]
Business Acquisition [Line Items]
Weighted average life of intangible assets				5 years 10 months 24 days