Note 2 - Restatement of Previously Issued Financial Statements - Summary of Effects of Restatements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 30, 2017	Dec. 31, 2016	Mar. 31, 2017
Net Sales	$ 387,689	$ 356,767	$ 1,015,086	$ 981,508
Cost of Products Sold	357,188	318,841	951,639	890,602
Gross Profit	30,501	37,926	63,447	90,906
Operating Income/(Loss)	10,271	14,341	9,475	29,933
Earnings/(Loss) Before Income Taxes	6,259	12,260	(1,166)	23,724
Income Tax (Benefit) Expense	1,882	4,471	(1,605)	8,149
Net earnings	$ 4,377	$ 7,789	$ 439	$ 15,575
Earnings Per Common Share-Basic (in dollars per share)	$ 0.45	$ 0.79	$ 0.04	$ 1.58
Earnings Per Common Share-Diluted (in dollars per share)	$ 0.44	$ 0.78	$ 0.04	$ 1.57
Inventory	$ 770,702	$ 699,445	$ 770,702	$ 699,445	$ 628,935
Total Current Assets	855,094	793,233	855,094	793,233	719,149
Total Assets	1,134,237	1,053,746	1,134,237	1,053,746	978,268
Deferred Revenue	80,151	60,553	80,151	60,553	46,100
Total Current Liabilities	242,033	238,771	242,033	238,771	177,764
Total Liabilities	711,832	647,136	711,832	647,136	553,064
Stockholders' Equity	422,405	406,610	422,405	406,610	425,204
Total Liabilities and Stockholders' Equity	1,134,237	1,053,746	1,134,237	1,053,746	978,268
Previously Reported [Member]
Net Sales	392,714	369,705	1,049,209	979,566
Cost of Products Sold	361,013	332,230	981,344	891,904
Gross Profit	31,701	37,475	67,865	87,662
Operating Income/(Loss)	11,471	13,890	13,893	26,689
Earnings/(Loss) Before Income Taxes	7,459	11,809	3,252	20,480
Income Tax (Benefit) Expense	(268)	3,628	(2,524)	6,217
Net earnings	$ 7,727	$ 8,181	$ 5,776	$ 14,263
Earnings Per Common Share-Basic (in dollars per share)	$ 0.79	$ 0.83	$ 0.59	$ 1.44
Earnings Per Common Share-Diluted (in dollars per share)	$ 0.78	$ 0.82	$ 0.58	$ 1.43
Inventory	$ 710,118	$ 656,368	$ 710,118	$ 656,368	598,056
Total Current Assets	794,510	750,156	794,510	750,156	688,270
Total Assets	1,072,003	1,004,711	1,072,003	1,004,711	946,019
Deferred Revenue	545	473	545	473	545
Total Current Liabilities	162,423	178,732	162,423	178,732	132,277
Total Liabilities	635,204	587,097	635,204	587,097	511,758
Stockholders' Equity	436,799	417,614	436,799	417,614	434,261
Total Liabilities and Stockholders' Equity	1,072,003	1,004,711	1,072,003	1,004,711	946,019
Restatement Adjustment [Member]
Net Sales	(5,025)	(12,938)	(34,123)	1,942
Cost of Products Sold	(3,825)	(13,389)	(29,705)	(1,302)
Gross Profit	(1,200)	451	(4,418)	3,244
Operating Income/(Loss)	(1,200)	451	(4,418)	3,244
Earnings/(Loss) Before Income Taxes	(1,200)	451	(4,418)	3,244
Income Tax (Benefit) Expense	2,150	843	919	1,932
Net earnings	$ (3,350)	$ (392)	$ (5,337)	$ 1,312
Earnings Per Common Share-Basic (in dollars per share)	$ (0.34)	$ (0.04)	$ (0.55)	$ 0.14
Earnings Per Common Share-Diluted (in dollars per share)	$ (0.34)	$ (0.04)	$ (0.54)	$ 0.14
Inventory	$ 60,584	$ 43,077	$ 60,584	$ 43,077	30,879
Total Current Assets	60,584	43,077	60,584	43,077	30,879
Total Assets	62,234	49,035	62,234	49,035	32,249
Deferred Revenue	79,606	60,080	79,606	60,080	45,555
Total Current Liabilities	79,610	60,039	79,610	60,039	45,487
Total Liabilities	76,628	60,039	76,628	60,039	41,306
Stockholders' Equity	(14,394)	(11,004)	(14,394)	(11,004)	(9,057)
Total Liabilities and Stockholders' Equity	$ 62,234	$ 49,035	$ 62,234	$ 49,035	$ 32,249