Segment Reporting (Summary Of Revenue By Product And Service Category) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Segment Reporting Information [Line Items]
Revenue	$ 322,676	$ 292,672
CAG Segment Revenue [Member]
Segment Reporting Information [Line Items]
Revenue	268,073	240,589
CAG Segment Revenue [Member] | Instruments And Consumables [Member]
Segment Reporting Information [Line Items]
Revenue	101,997	93,887
CAG Segment Revenue [Member] | Rapid Assay Products [Member]
Segment Reporting Information [Line Items]
Revenue	43,664	38,617
CAG Segment Revenue [Member] | Reference Laboratory Diagnostic And Consulting Services [Member]
Segment Reporting Information [Line Items]
Revenue	101,862	89,128
CAG Segment Revenue [Member] | Practice Management Systems And Digital Radiography [Member]
Segment Reporting Information [Line Items]
Revenue	20,550	18,957
Water Segment Revenue [Member]
Segment Reporting Information [Line Items]
Revenue	19,582	18,965
LPD Segment Revenue [Member]
Segment Reporting Information [Line Items]
Revenue	22,182	23,939
Other Segment Revenue [Member]
Segment Reporting Information [Line Items]
Revenue	$ 12,839	$ 9,179