Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Revenues	$ 37,082	$ 39,094	$ 73,763	$ 75,763
Operating income	7,154	10,149	13,881	17,702
Radiation Measurement [Member]
Revenues	27,249	27,358	53,652	54,402
Operating income	6,118	8,029	11,383	14,319
Medical Physics [Member]
Revenues	7,598	7,688	15,187	15,122
Operating income	732	109	1,524	1,002
Medical Products [Member]
Revenues	2,235	4,048	4,924	6,239
Operating income	$ 304	$ 2,011	$ 974	$ 2,381

Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration