Segment Information (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2017 USD ($) segment	Mar. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)
Segment Reporting Information [Line Items]
Reporting segments | segment			2
Consolidated revenues	$ 39,122,000	$ 38,082,000	$ 76,694,000	$ 74,612,000
Consolidated operating income	7,809,000	7,217,000	15,251,000	13,469,000
Consolidated Assets	190,508,000		190,508,000		$ 190,816,000
Eliminations [Member]
Segment Reporting Information [Line Items]
Consolidated Assets	(12,893,000)		(12,893,000)		(12,918,000)
Radiation Measurement [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	28,692,000	25,520,000	56,324,000	50,224,000
Consolidated operating income	11,409,000	9,969,000	22,641,000	18,867,000
Consolidated Assets	159,090,000		159,090,000		160,560,000
Medical Physics [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	10,430,000	10,033,000	20,370,000	19,386,000
Consolidated operating income	672,000	918,000	1,351,000	1,696,000
Consolidated Assets	44,311,000		44,311,000		$ 43,174,000
Medical Products [Member]
Segment Reporting Information [Line Items]
Consolidated revenues	0	2,529,000	0	5,002,000
Consolidated operating income		432,000		922,000
Corporate [Member]
Segment Reporting Information [Line Items]
Consolidated operating income	$ (4,272,000)	$ (4,102,000)	$ (8,741,000)	$ (8,016,000)