Goodwill and Other Intangible Assets (Gross Carrying Amount and Accumulated Amortization of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Changes in gross carrying amount and accumulated amortization of goodwill
Gross carrying amount, balance at the beginning of the period	$ 1,214,285
Accumulated impairment loss, balance at the beginning of the period	(1,005,000)
Accumulated amortization, balance at the beginning of the period	(11,724)
Gross carrying amount, foreign exchange/impairment	(1,361)
Accumulated impairment loss, foreign exchange/impairment	0
Accumulated amortization, foreign exchange/impairment	24
Gross carrying amount, balance at the end of the period	1,212,924
Accumulated impairment loss, balance at the end of the period	(1,005,000)
Accumulated amortization, balance at the end of the period	(11,700)
Research Models and Services [Member]
Changes in gross carrying amount and accumulated amortization of goodwill
Gross carrying amount, balance at the beginning of the period	56,402
Accumulated amortization, balance at the beginning of the period	(3,721)
Gross carrying amount, foreign exchange/impairment	(275)
Accumulated impairment loss, foreign exchange/impairment	0
Accumulated amortization, foreign exchange/impairment	24
Gross carrying amount, balance at the end of the period	56,127
Accumulated amortization, balance at the end of the period	(3,697)
Preclinical Services [Member]
Changes in gross carrying amount and accumulated amortization of goodwill
Gross carrying amount, balance at the beginning of the period	1,157,883
Accumulated impairment loss, balance at the beginning of the period	(1,005,000)
Accumulated amortization, balance at the beginning of the period	(8,003)
Gross carrying amount, foreign exchange/impairment	(1,086)
Accumulated impairment loss, foreign exchange/impairment	0
Accumulated amortization, foreign exchange/impairment	0
Gross carrying amount, balance at the end of the period	1,156,797
Accumulated impairment loss, balance at the end of the period	(1,005,000)
Accumulated amortization, balance at the end of the period	$ (8,003)