2. Revenue: Schedule of changes in the contract assets and the contract liabilities (Details) $ in Thousands	3 Months Ended
	Jun. 28, 2019 USD ($)
Contract revenue recognized
Increase (Decrease) in Contract with Customer, Liability	$ (3,887)
Increase (Decrease) in Contract with Customer, Asset	(2,656)
Contract receivables recorded
Increase (Decrease) in Contract with Customer, Asset	2,877
Contract amount billed
Increase (Decrease) in Contract with Customer, Liability	$ 1,641