Segment Information (Financial Information For Each Reportable Segment) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Segment Reporting Information [Line Items]
Consolidated revenues	$ 39,888,000	$ 37,854,000	$ 116,582,000	$ 112,466,000
Consolidated operating income	8,583,000	7,713,000	23,834,000	21,182,000
Consolidated Assets	198,166,000		198,166,000		$ 190,816,000
Eliminations [Member]
Segment Reporting Information [Line Items]
Consolidated Assets	(15,635,000)		(15,635,000)		(12,918,000)
Radiation Measurement [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	29,594,000	27,492,000	85,918,000	77,716,000
Consolidated operating income	12,138,000	10,294,000	34,779,000	29,161,000
Consolidated Assets	165,720,000		165,720,000		160,560,000
Medical Physics [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	10,294,000	9,562,000	30,664,000	28,948,000
Consolidated operating income	789,000	756,000	2,140,000	2,452,000
Consolidated Assets	48,081,000		48,081,000		$ 43,174,000
Medical Products [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	0	800,000	0	5,802,000
Consolidated operating income		141,000		1,063,000
Corporate [Member]
Segment Reporting Information [Line Items]
Consolidated operating income	$ (4,344,000)	$ (3,478,000)	$ (13,085,000)	$ (11,494,000)