(Loss) Income Per Common Share (Computation Of Net Income Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
(Loss) Income Per Common Share [Abstract]
Net (loss) income attributed to Landauer, Inc.	$ 2,797	$ (36,335)	$ 4,514	$ 3,821	$ 7,758	$ (13,663)	$ 4,430	$ 4,257	$ (25,203)	$ 2,782	$ 18,546
Less: Income allocated to unvested restricted stock										165	137
Net (loss) income available to common stockholders									$ (25,203)	$ 2,617	$ 18,409
Basic weighted averages shares outstanding	9,524	9,482	9,460	9,422	9,462	9,439	9,417	9,336	9,524	9,434	9,389
Net (loss) income per share – Basic	$ 0.31	$ (3.83)	$ 0.47	$ 0.40	$ 0.82	$ (1.45)	$ 0.46	$ 0.45	$ (2.65)	$ 0.28	$ 1.96
Effect of dilutive securities										48	48
Diluted weighted averages shares outstanding	9,572	9,482	9,501	9,467	9,506	9,439	9,462	9,385	9,524	9,482	9,437
Net (loss) income per share - Diluted	$ 0.31	$ (3.83)	$ 0.47	$ 0.40	$ 0.81	$ (1.45)	$ 0.46	$ 0.45	$ (2.65)	$ 0.27	$ 1.95