Goodwill and Other Intangible Assets - Gross Carrying Amount and Accumulated Amortization of Goodwill (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 28, 2015
Changes in gross carrying amount and accumulated amortization of goodwill
Gross carrying amount, balance at the beginning of the period	$ 321,077us-gaap_GoodwillGross
Adjustments to Goodwill, Acquisitions	(437)us-gaap_GoodwillAcquiredDuringPeriod
Adjustments to Goodwill, Foreign Exchange	(7,481)
Gross carrying amount, balance at the end of the period	313,159us-gaap_GoodwillGross
Research Models and Services
Changes in gross carrying amount and accumulated amortization of goodwill
Gross carrying amount, balance at the beginning of the period	59,196
Adjustments to Goodwill, Acquisitions	0
Adjustments to Goodwill, Foreign Exchange	(411)
Gross carrying amount, balance at the end of the period	58,785
Discovery and Safety Assessment
Changes in gross carrying amount and accumulated amortization of goodwill
Gross carrying amount, balance at the beginning of the period	229,302
Adjustments to Goodwill, Acquisitions	(624)
Adjustments to Goodwill, Foreign Exchange	(5,547)
Gross carrying amount, balance at the end of the period	223,131
Manufacturing Support
Changes in gross carrying amount and accumulated amortization of goodwill
Gross carrying amount, balance at the beginning of the period	32,579
Adjustments to Goodwill, Acquisitions	187
Adjustments to Goodwill, Foreign Exchange	(1,523)
Gross carrying amount, balance at the end of the period	$ 31,243

The increase or decrease to the recorded value of goodwill due to foreign currency translation adjustments and other increases and decreases that are not separately disclosed.

No definition available.

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- 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

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- 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

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