Fair value measurements - Estimated fair value of long-term debt, including current maturities (Details) - Level 2 - USD ($) $ in Thousands	Jun. 27, 2020	Mar. 28, 2020	Jun. 29, 2019
Fair value measurements
Total fair value of debt	$ 270,515	$ 285,365	$ 295,942
The 2019 Elfa Revolving Credit Facility
Fair value measurements
Total fair value of debt	5,533	9,050	9,951
Revolving credit facility
Fair value measurements
Total fair value of debt	58,000	78,000	31,000
Senior secured term loan facility
Fair value measurements
Total fair value of debt	206,728	198,041	254,729
Obligations under capital leases
Fair value measurements
Total fair value of debt	$ 254	$ 274	$ 262