Commitments and contigencies (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Commitments And Contingencies (Textual) [Abstract]
Rental expense under the office and distribution facilities leases, excluding the discontinued operations of PMG	$ 30.2	$ 40.3	$ 27.8
Annual lease commitments for a new facility	3.3
Capital lease obligations	4.2
Terms of noncancelable lease agreements Range	10 years
Capital lease obligations as offset against industrial bonds	4.2
Insurance recovery for previously incurred litigation costs			15.0
Incurred to the settlement of a lawsuit			35.0
Noncancelable lease agreement period range	one to ten years
Extended agreement of renewable options range	one to five years
Settlement for a claim regarding interpretation of certain contractual terms	30.0
Accrual for a loss both probable and estimable recorded as an offset to revenues	$ 30.0
Supplier Concentration Risk [Member]
Concentration Risk [Line Items]
Pharmaceutical purchases from one wholesaler in percent	58.70%