Segment Information - Segment Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Segment Reporting Information [Line Items]
Revenues from external customers	$ 31,803,000	$ 27,450,000	$ 31,185,000	$ 26,683,000	$ 28,990,000	$ 21,574,000	$ 25,962,000	$ 26,321,000	$ 117,121,000	$ 102,847,000	$ 100,003,000
Intersegment revenues
Depreciation									2,653,000	2,664,000	2,487,000
Operating earnings (loss) before income taxes									5,221,000	2,539,000	2,962,000
Income tax expense (benefit)									1,540,000	739,000	864,000
Net earnings attributable to noncontrolling interest	187,000	238,000	158,000	54,000	558,000	156,000	(31,000)	86,000	637,000	769,000	248,000
Net earnings (loss) attributable to Kewaunee Scientific Corporation	1,217,000	544,000	649,000	634,000	1,256,000	(122,000)	(125,000)	22,000	3,044,000	1,031,000	1,850,000
Segment assets	68,742,000				63,361,000				68,742,000	63,361,000	63,058,000
Expenditures for segment assets									2,405,000	1,435,000	5,247,000
Revenues (excluding intersegment) to customers in foreign countries									24,544,000	20,593,000	18,545,000
Domestic Operations [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									93,519,000	83,971,000	84,121,000
Intersegment revenues									6,722,000	5,290,000	3,825,000
Depreciation									2,523,000	2,513,000	2,312,000
Operating earnings (loss) before income taxes									6,908,000	3,400,000	5,150,000
Income tax expense (benefit)									2,025,000	1,349,000	1,650,000
Net earnings attributable to noncontrolling interest
Net earnings (loss) attributable to Kewaunee Scientific Corporation									4,883,000	2,051,000	3,500,000
Segment assets	52,252,000				49,373,000				52,252,000	49,373,000	52,812,000
Expenditures for segment assets									2,314,000	1,395,000	5,070,000
Revenues (excluding intersegment) to customers in foreign countries									942,000	1,717,000	2,663,000
International Operations [Member]
Segment Reporting Information [Line Items]
Revenues from external customers									23,602,000	18,876,000	15,882,000
Intersegment revenues									2,443,000	3,051,000	1,297,000
Depreciation									130,000	151,000	175,000
Operating earnings (loss) before income taxes									2,622,000	2,472,000	1,008,000
Income tax expense (benefit)									786,000	779,000	188,000
Net earnings attributable to noncontrolling interest									637,000	769,000	248,000
Net earnings (loss) attributable to Kewaunee Scientific Corporation									1,199,000	924,000	572,000
Segment assets	16,490,000				13,988,000				16,490,000	13,988,000	10,246,000
Expenditures for segment assets									91,000	40,000	177,000
Revenues (excluding intersegment) to customers in foreign countries									23,602,000	18,876,000	15,882,000
Corporate [Member]
Segment Reporting Information [Line Items]
Revenues from external customers
Intersegment revenues									(9,165,000)	(8,341,000)	(5,122,000)
Depreciation
Operating earnings (loss) before income taxes									(4,309,000)	(3,333,000)	(3,196,000)
Income tax expense (benefit)									(1,271,000)	(1,389,000)	(974,000)
Net earnings attributable to noncontrolling interest
Net earnings (loss) attributable to Kewaunee Scientific Corporation									(3,038,000)	(1,944,000)	(2,222,000)
Segment assets
Expenditures for segment assets
Revenues (excluding intersegment) to customers in foreign countries