XML 46 R33.htm IDEA: XBRL DOCUMENT
v3.4.0.3

Goodwill and Identifiable Assets (Goodwill) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Goodwill [Roll Forward] |  |  |
Gross goodwill | $ 875,657 | $ 874,906 | $ 512,060
Goodwill | 875,657 | 874,906 |
Translation adjustment | 751 | (1,632) |
Apex |  |  |
Goodwill [Roll Forward] |  |  |
Gross goodwill | 644,972 | 644,617 | 287,951
Translation adjustment | 355 | (1,363) |
Oxford |  |  |
Goodwill [Roll Forward] |  |  |
Gross goodwill | 230,685 | 230,289 | $ 224,109
Translation adjustment | $ 396 | (269) |
Creative Circle [Member] |  |  |
Goodwill [Roll Forward] |  |  |
Goodwill, Acquired During Period |  | 358,029 |
Creative Circle [Member] | Apex |  |  |
Goodwill [Roll Forward] |  |  |
Goodwill, Acquired During Period |  | 358,029 |
Creative Circle [Member] | Oxford |  |  |
Goodwill [Roll Forward] |  |  |
Goodwill, Acquired During Period |  | 0 |
LabResource [Member] |  |  |
Goodwill [Roll Forward] |  |  |
Goodwill, Acquired During Period |  | 6,449 |
LabResource [Member] | Apex |  |  |
Goodwill [Roll Forward] |  |  |
Goodwill, Acquired During Period |  | 0 |
LabResource [Member] | Oxford |  |  |
Goodwill [Roll Forward] |  |  |
Goodwill, Acquired During Period |  | $ 6,449 |

X
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266 + Details
Name: | us-gaap_Goodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillAcquiredDuringPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a,h) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_GoodwillRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) from foreign currency translation adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillTranslationAdjustments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=asgn_ApexSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=asgn_OxfordSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=asgn_CreativeCircleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=asgn_LabResourceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |