Employee benefit plans - Pension plan (Details) - Pension plan - USD ($) $ in Thousands	12 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 31, 2018
Change in benefit obligation:
Projected benefit obligation, beginning of year	$ 4,862	$ 4,900
Service cost	46	51	$ 37
Interest cost	119	141	143
Benefits paid	(145)	(85)
Actuarial loss	1,240	364
Exchange rate gain	(345)	(509)
Projected benefit obligation, end of year	5,777	4,862	4,900
Underfunded status, end of year	$ (5,777)	$ (4,862)
Discount rate (as a percent)	1.30%	2.60%
Rate of pay increases (as a percent)	3.00%	3.00%
Components of net periodic benefit cost:
Service cost	$ 46	$ 51	37
Interest cost	119	141	143
Amortization of unrecognized net loss	73	68	63
Net periodic benefit cost for defined benefit plan	238	260	243
Defined contribution plans	1,661	2,078	2,237
Total net periodic benefit cost	$ 1,899	$ 2,338	$ 2,480
Elfa
Pension plans
Percentage of employees who are plan participants	3.00%