Note 8 - Plant Restructuring - Restructuring Reserve (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2017	Jul. 01, 2017	Oct. 01, 2016	Jul. 02, 2016	Sep. 30, 2017	Oct. 01, 2016
Balance		$ 5,115		$ 8,872	$ 5,115	$ 8,872
Quarter charge (credit)	$ (25)	81	$ 277	1,185	56	1,462
Cash payments/write offs					(4,269)	(3,125)
Balance	902		7,209		902	7,209
Employee Severance [Member]
Balance		37			37
Quarter charge (credit)		36	112	127
Cash payments/write offs					(73)	(123)
Balance			116			116
Impairment of Long-Lived Assets [Member]
Balance		4,773		4,975	4,773	4,975
Quarter charge (credit)	8	9	(286)	(6)
Cash payments/write offs					(3,888)	240
Balance	902		4,923		902	4,923
Other Restructuring [Member]
Balance		305		3,897	305	3,897
Quarter charge (credit)	(33)	$ 36	451	$ 1,064
Cash payments/write offs					(308)	(3,242)
Balance			$ 2,170			$ 2,170