Segment Information - Schedule of Results by Business Segment (Detail) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Jan. 31, 2016		Jan. 31, 2015	[2]	Jan. 31, 2016		Jan. 31, 2015	[2]
Segment Reporting Information [Line Items]
Total net sales		$ 210,786	[1]	$ 130,550		$ 501,791	[1]	$ 370,865
Cost of sales		124,128	[1]	86,726		300,048	[1]	243,083
Gross margin		86,658	[1]	43,824		201,743	[1]	127,782
Operating income		50,148	[1]	15,611		101,747	[1]	52,058
Income tax expense		16,630	[1]	4,554		31,844	[1]	16,526
Intersegment eliminations
Segment Reporting Information [Line Items]
Total net sales	[1]	(861)				(1,504)
Cost of sales	[1]	(923)				(1,504)
Gross margin	[1]	62
Operating income	[1]	62
Operating Segments
Segment Reporting Information [Line Items]
Total net sales		210,786	[1]	130,550		501,791	[1]	370,865
Firearms Division
Segment Reporting Information [Line Items]
Total net sales		194,650	[1]	124,490		453,961	[1]	364,805
Firearms Division | Intersegment eliminations
Segment Reporting Information [Line Items]
Total net sales	[1]	795				795
Firearms Division | Operating Segments
Segment Reporting Information [Line Items]
Total net sales		195,445	[1]	124,490		454,756	[1]	364,805
Cost of sales		117,284	[1]	81,958		278,147	[1]	238,315
Gross margin		78,160	[1]	42,532		177,174	[1]	126,490
Operating income		49,137	[1]	17,571		99,104	[1]	54,018
Income tax expense		16,427	[1]	5,280		31,110	[1]	17,252
Accessories
Segment Reporting Information [Line Items]
Total net sales		16,136	[1]	6,060		47,830	[1]	6,060
Accessories | Intersegment eliminations
Segment Reporting Information [Line Items]
Total net sales	[1]	(66)				(709)
Accessories | Operating Segments
Segment Reporting Information [Line Items]
Total net sales		16,202	[1]	6,060		48,539	[1]	6,060
Cost of sales		7,767	[1]	4,768	[3]	23,405	[1]	4,768	[3]
Gross margin		8,436	[1]	1,292	[3]	24,569	[1]	1,292	[3]
Operating income		949	[1],[4]	(1,960)	[5]	2,643	[1],[4]	(1,960)	[5]
Income tax expense		$ 203	[1]	$ (726)		$ 734	[1]	$ (726)

[1] We allocate all of corporate overhead expenses, such as general and administrative expenses and other corporate-level expenses, to both our firearm and accessories segments.

[2] Results of operations for the three and nine months ended January 31, 2015 include activity for the period subsequent to the BTI Acquisition. Due to the timing of the BTI Acquisition, the segment data above includes all corporate overhead expenses in our firearms segment.

[3] Amount includes $1.8 million of additional cost of goods sold from the fair value step-up in inventory at the date of the BTI Acquisition.

[4] Amount includes $2.6 million and $7.2 million for the three and nine months ended January 31, 2016, respectively, of amortization of intangible assets identified as a result of the BTI Acquisition.

[5] Amount includes $1.3 million for the three and nine months ended January 31, 2015, of amortization of intangible assets identified as a result of the BTI Acquisition.