Income Per Common Share (Computation Of Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Per Common Share [Abstract]
Net income attributed to Landauer, Inc.	$ 6,400	$ 7,265	$ 15,976	$ 15,187
Less: Income allocated to unvested restricted stock	15	20	53	59
Net income available to common stockholders	$ 6,385	$ 7,245	$ 15,923	$ 15,128
Basic weighted average shares outstanding	9,585	9,531	9,562	9,523
Net income per share - Basic	$ 0.67	$ 0.76	$ 1.67	$ 1.59
Effect of dilutive securities	$ 21	$ 33	$ 33	$ 32
Diluted weighted averages shares outstanding	9,606	9,564	9,595	9,555
Net income per share - Diluted	$ 0.66	$ 0.76	$ 1.66	$ 1.58
Dividends paid per share	$ 0.275	$ 0.275	$ 0.83	$ 0.83