Quarterly Financial Information (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	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
Quarterly Financial Information [Line Items]
Gross profit	$ 68,488	[1]	$ 50,099	$ 48,523	$ 51,293	$ 46,863	$ 30,004	$ 24,606	$ 26,516	$ 218,403	$ 127,989	$ 104,688
Adjustment To Gross Profit
Quarterly Financial Information [Line Items]
Gross profit	$ 3,000

[1] Gross profit for the fourth fiscal quarter included a $3.0 million adjustment for the recall of our Thompson/Center Arms bolt action rifles.