Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended								12 Months Ended
	Jun. 30, 2010	Jul. 31, 2009	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
Significant Accounting Policies [Line Items]
Net sales			$ 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
Equipment under capital lease							307,000					307,000
Property plant and equipment impairment charges											0	0	0
Assets held in trust account for non-qualified benefit plans included in other assets			4,077,000				3,454,000				4,077,000	3,454,000
Cash surrender value of life insurance policies included in other assets			96,000				83,000				96,000	83,000
Retainage included in accounts receivable			2,659,000				2,015,000				2,659,000	2,015,000
Research and development costs											872,000	941,000	1,181,000
Advertising costs											395,000	344,000	398,000
Interest rate swap, conversion rate	4.875%	3.90%
Interest rate swap, beginning date of conversion	Aug. 02, 2010	Aug. 03, 2009
Interest rate swap, ending date of conversion		Aug. 01, 2012
Antidilutive options exclude from computation of earning per share											72,850	253,050	118,900
Stock options granted											40,000	55,000	136,400
Revolving Credit Facility [Member]
Significant Accounting Policies [Line Items]
Outstanding advances under the revolving credit facility		2,000,000	15,000,000								15,000,000
VWR International LLC [Member]
Significant Accounting Policies [Line Items]
Revenue percentage from national stocking distributor											11.00%	12.00%	14.00%
Kewaunee Labway Asia Pte. Ltd. [Member]
Significant Accounting Policies [Line Items]
Percentage of controlling interest in subsidiaries			51.00%								51.00%
Kewaunee Labway India Pvt. Ltd. [Member]
Significant Accounting Policies [Line Items]
Percentage of controlling interest in subsidiaries			90.00%								90.00%
Kewaunee Scientific Corporation India Pvt. Ltd. [Member]
Significant Accounting Policies [Line Items]
Percentage of controlling interest in subsidiaries			100.00%								100.00%
Kewaunee Scientific Corporation Singapore Pte. Ltd. [Member]
Significant Accounting Policies [Line Items]
Percentage of controlling interest in subsidiaries			100.00%								100.00%
Subsidiaries [Member]
Significant Accounting Policies [Line Items]
Net assets			11,189,000				9,648,000				11,189,000	9,648,000
Net sales											$ 23,602,000	$ 18,876,000	$ 15,882,000