Revenue from Contracts with Customers (Details Narrative) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 29, 2018 USD ($) $ / shares	Jun. 30, 2018 USD ($)	Sep. 30, 2017 USD ($) $ / shares	Jul. 01, 2017 USD ($)	Sep. 29, 2018 USD ($) Segment $ / shares	Sep. 30, 2017 USD ($) $ / shares	Apr. 03, 2018 USD ($)	Mar. 31, 2018 USD ($)
Retained earnings	$ 594,279				$ 594,279			$ 536,978
Operating income	35,884		$ 25,437		71,882	$ 57,396
Net income	$ 30,111	$ 27,467	$ 14,823	$ 21,809	$ 57,578	$ 36,632
Basic income per share (in dollars per share) | $ / shares	$ 1.24		$ 0.62		$ 2.38	$ 1.53
Diluted income per share (in dollars per share) | $ / shares	$ 1.22		$ 0.61		$ 2.34	$ 1.51
Inventory work-in-process	$ 88,010				$ 88,010			77,890
Transaction price allocated to remaining performance obligations	1 year				1 year
The aggregate amount of the transaction price allocated to remaining performance obligations	$ 200,250				$ 200,250
Remaining performance obligations over the next 12 months	67.00%				67.00%
Remaining performance obligations over the next 24 months	95.00%				95.00%
Revenue recognize remaining performance obligations					<p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"><font style="font: 10pt Times New Roman, Times, Serif">The remaining performance obligations over the next 12 months, with the remainder being recognized within 24 months.</font></p>
Accounts receivable with customers, Gross	$ 119,521				$ 119,521			$ 116,890
Number of segment | Segment					4
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Retained earnings	97				$ 97		$ (277)
Contract assets							1,323
Contract liabilities							754
Sales	(269)				871
Operating income	(90)				460
Net income	(80)				$ 393
Basic income per share (in dollars per share) | $ / shares					$ 0.02
Diluted income per share (in dollars per share) | $ / shares					$ 0.02
Inventory work-in-process	(1,172)				$ (1,172)		$ (847)
Prepaids and other current assets	2,154				2,154
Accrued expenses and other current liabilities	$ 735				$ 735