Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 31, 2017	Jan. 01, 2017
Income Statement [Abstract]
Sales	$ 118,053	$ 112,351	$ 377,179	$ 364,975
Cost of sales	(99,213)	(91,439)	(308,225)	(288,815)
Gross profit	18,840	20,912	68,954	76,160
Selling, general and administrative expenses	(14,139)	(14,916)	(44,733)	(44,913)
Operating income	4,701	5,996	24,221	31,247
Interest expense, net	(857)	(634)	(2,423)	(1,977)
Income before income taxes	3,844	5,362	21,798	29,270
Income tax benefit (expense)	13,299	(1,811)	6,386	(10,925)
Net income	$ 17,143	$ 3,551	$ 28,184	$ 18,345
Weighted average number of shares outstanding - basic	10,609,078	10,538,328	10,599,232	10,529,259
Weighted average number of shares outstanding - diluted	10,648,232	10,595,140	10,641,578	10,592,550
Basic earnings per share
Basic earnings per share	$ 1.62	$ 0.34	$ 2.66	$ 1.74
Diluted earnings per share
Diluted earnings per share	1.61	0.34	2.65	1.73
Cash dividends declared per common share	$ 0	$ 0	$ 0.44	$ 0.42