Goodwill And Intangible Assets (Changes In The Carrying Amount Of Goodwill, By Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
Sep. 30, 2015	Mar. 31, 2016
Goodwill [Line Items]
Goodwill	$ 99,140	$ 99,308
Accumulated impairment losses	(64,068)	(64,068)
Goodwill	35,072	35,240
Effects of foreign currency	168
Radiation Measurement [Member]
Goodwill [Line Items]
Goodwill	11,002	11,161
Goodwill	11,002	11,161
Effects of foreign currency	159
Medical Physics [Member]
Goodwill [Line Items]
Goodwill	22,611	22,611
Goodwill	22,611	22,611
Medical Products [Member]
Goodwill [Line Items]
Goodwill	65,527	65,536
Accumulated impairment losses	(64,068)	(64,068)
Goodwill	1,459	$ 1,468
Effects of foreign currency	$ 9

Amount after 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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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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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from foreign currency translation adjustments 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 (f)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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