Summary Of Significant Accounting Policies (Net Income (Loss) And Diluted Net Income (Loss) Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended			36 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	Sep. 30, 2011
Dosimetry devices		$ 1,821	$ 3,177	$ 3,375		$ 2,264	$ 2,213	$ 2,368	$ 12,506	$ 11,163	$ 11,816
Equity in joint ventures		256	535	1,281		12	143	1,057	2,939	3,251	3,103
Income (loss) before taxes		(60,259)	6,389	5,928		(17,967)	6,305	6,674	(40,498)	3,076	27,580
Income tax expense (benefit)		(24,225)	1,913	1,899		(4,449)	1,799	2,244	(15,800)	(560)	8,206
Less amounts attributed to noncontrolling interest		301	(38)	208		145	76	173	505	854	828
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
Diluted Net Income (Loss) Per Share	$ 0.31	$ (3.83)	$ 0.47	$ 0.40	$ 0.81	$ (1.45)	$ 0.46	$ 0.45	$ (2.65)	$ 0.27	$ 1.95
Previously Reported [Member]
Dosimetry devices		1,830	3,150	3,158		2,490	2,187	2,255		11,161	11,903
Equity in joint ventures		256	535	573		471	556	1,528		3,881	3,181
Income (loss) before taxes		(61,347)	6,917	4,743		(17,347)	6,853	7,317		4,480	28,140
Income tax expense (benefit)		(25,030)	1,954	1,496		(3,748)	1,620	2,274		(1,216)	8,040
Less amounts attributed to noncontrolling interest		309	(34)	196		154	80	166		860	830
Net (loss) income attributed to Landauer, Inc.		(36,626)	4,997	3,051		(13,753)	5,153	4,877		4,836	19,270
Diluted Net Income (Loss) Per Share		$ (3.86)	$ 0.52	$ 0.32		$ (1.46)	$ 0.54	$ 0.52		$ 0.49	$ 2.03
Adjustments [Member]
Revenue and accounts receivable		1,138	(500)	252		(22)		32		(407)	(211)	(1,100)
Dosimetry devices		13	13	12		(44)	(44)	(44)		(177)	(130)	(1,335)
Long-term investments		(48)	(25)	79		(28)	(24)	43		(35)	(10)	(111)
Sales taxes		(15)	(16)	(16)		(17)	(17)	(17)		(69)	(67)	(281)
Intangible assets				150		(50)	(50)	(50)		50	(200)
Equity in joint ventures				708		(459)	(413)	(471)		(630)	(78)
Employee bonuses								(136)		(136)	136
Foreign currency transaction gains & losses												316
Income (loss) before taxes		1,088	(528)	1,185		(620)	(548)	(643)		(1,404)	(560)	(2,511)
Income tax expense (benefit)		805	(41)	403		(701)	179	(30)		656	166	(640)
Less amounts attributed to noncontrolling interest		(8)	(4)	12		(9)	(4)	7		(6)	(2)	(49)
Net (loss) income attributed to Landauer, Inc.		$ 291	$ (483)	$ 770		$ 90	$ (723)	$ (620)		$ (2,054)	$ (724)	$ (1,822)
Total adjustments, Diluted Net Income (Loss) Per Share		$ 0.11	$ (0.05)	$ 0.12		$ (0.06)	$ (0.06)	$ (0.07)		$ (0.15)	$ (0.06)
Income tax expense (benefit), Diluted Net Income (Loss) Per Share		$ 0.08		$ 0.04		$ (0.07)	$ 0.02			$ 0.07	$ 0.02
Diluted Net Income (Loss) Per Share		$ 0.03	$ (0.05)	$ 0.08		$ 0.01	$ (0.08)	$ (0.07)		$ (0.22)	$ (0.08)