XML 36 R37.htm IDEA: XBRL DOCUMENT v2.4.0.8
Warranty Reserve - Additional Information (Detail) (USD $)
6 Months Ended
Oct. 31, 2013
Oct. 31, 2012
Apr. 30, 2013
Apr. 30, 2012
Aug. 22, 2013
M&P Shield TM
Standard Product Warranty Accrual [Line Items]          
Accrued warranty $ 7,484,000 $ 6,113,000 $ 8,423,000 $ 6,412,000 $ 370,000
Remaining cost related to recall costs 3,400,000        
Warranty expense $ 908,000 $ 1,600,000