Business Segments Information - Schedule of Additional Financial Information Attributable to Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 383,329	$ 366,714	$ 732,453	$ 693,148
Gross profit	83,735	69,763	156,321	130,621
Segment Adjusted EBITDA	60,943	55,200	112,754	100,328
Interest expense, net	4,947	5,044	9,233	10,095
Depreciation and amortization	17,367	16,374	36,005	32,400
Equity in net (loss) income of unconsolidated affiliates	(372)	(62)	(18)	(724)
Capital expenditures	9,602	8,164	20,197	15,596
Investments in unconsolidated affiliates	17,701		17,701		$ 25,038
Total identifiable assets	1,106,635		1,106,635		1,041,699
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total identifiable assets	(66,412)		(66,412)		(69,193)
Domestic [Member]
Segment Reporting Information [Line Items]
Net sales	327,300	319,776	625,466	609,401
Gross profit	73,475	65,574	133,134	119,641
Segment Adjusted EBITDA	56,677	53,904	97,955	94,896
Interest expense, net	4,901	5,020	8,938	10,062
Depreciation and amortization	15,243	14,937	31,659	29,595
Equity in net (loss) income of unconsolidated affiliates	(12)	251	324	404
Capital expenditures	7,631	7,869	16,475	14,788
Investments in unconsolidated affiliates	3,075		3,075		7,957
Domestic [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total identifiable assets	1,010,171		1,010,171		942,267
International Segment [Member]
Segment Reporting Information [Line Items]
Net sales	56,029	46,938	106,987	83,747
Gross profit	10,260	4,189	23,187	10,980
Segment Adjusted EBITDA	4,266	1,296	14,799	5,432
Interest expense, net	46	24	295	33
Depreciation and amortization	2,124	1,437	4,346	2,805
Equity in net (loss) income of unconsolidated affiliates	(360)	(313)	(342)	(1,128)
Capital expenditures	1,971	$ 295	3,722	$ 808
Investments in unconsolidated affiliates	14,626		14,626		17,081
International Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total identifiable assets	$ 162,876		$ 162,876		$ 168,624