Business Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 division segment	Mar. 31, 2011	Dec. 31, 2011
Business Segment Information
Number of operating segments	5
Number of divisions	5
Revenue:
Product and service revenue between reportable segments	$ (2.5)	$ (2.8)
Total revenue	405.6	357.0
Operating Income (Loss):
Total operating income	34.4	25.7
Interest and other income (expense), net	(7.5)	(5.0)
Income before income taxes and noncontrolling interest in consolidated subsidiaries	26.9	20.7
Assets:
Total assets	1,797.3		1,710.5
Scientific Instruments
Revenue:
Total revenue	378.1	335.8
Operating Income (Loss):
Total operating income	35.1	27.7
Assets:
Total assets	1,759.0		1,675.0
Energy and Supercon Technologies
Revenue:
Total revenue	30.0	24.0
Operating Income (Loss):
Total operating income	(0.3)	(0.7)
Assets:
Total assets	112.2		104.4
Corporate, eliminations and other
Operating Income (Loss):
Total operating income	(0.4)	(1.3)
Assets:
Total assets	$ (73.9)		$ (68.9)