Accumulated other comprehensive income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 25, 2022	Mar. 26, 2021	Mar. 25, 2022	Mar. 26, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 1,199,191	$ 1,036,670	$ 1,112,520	$ 974,409
Other comprehensive income before reclassification adjustment			643	(4,304)
Amounts reclassified out of AOCI to the unaudited condensed consolidated statements of operations and comprehensive income			(1,265)	(1,488)
Tax effects			0	0
Total other comprehensive income (loss), net of tax	(1,699)	(5,282)	(622)	(5,792)
Ending balance	1,228,727	1,073,506	1,228,727	1,073,506
Unrealized net (Losses)/Gains on Available-for-sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			308	1,490
Other comprehensive income before reclassification adjustment			(3,602)	(758)
Amounts reclassified out of AOCI to the unaudited condensed consolidated statements of operations and comprehensive income			(13)	(179)
Tax effects			0	0
Total other comprehensive income (loss), net of tax			(3,615)	(937)
Ending balance	(3,307)	553	(3,307)	553
Unrealized net (Losses)/Gains on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(4,504)	602
Other comprehensive income before reclassification adjustment			4,443	(4,093)
Amounts reclassified out of AOCI to the unaudited condensed consolidated statements of operations and comprehensive income			(1,700)	(1,730)
Tax effects			0	0
Total other comprehensive income (loss), net of tax			2,743	(5,823)
Ending balance	(1,761)	(5,221)	(1,761)	(5,221)
Retirement benefit plan - Prior service cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(1,425)	(2,009)
Other comprehensive income before reclassification adjustment			0	0
Amounts reclassified out of AOCI to the unaudited condensed consolidated statements of operations and comprehensive income			448	421
Tax effects			0	0
Total other comprehensive income (loss), net of tax			448	421
Ending balance	(977)	(1,588)	(977)	(1,588)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance			(645)	(1,230)
Other comprehensive income before reclassification adjustment			(198)	547
Amounts reclassified out of AOCI to the unaudited condensed consolidated statements of operations and comprehensive income			0	0
Tax effects			0	0
Total other comprehensive income (loss), net of tax			(198)	547
Ending balance	(843)	(683)	(843)	(683)
AOCI Attributable to parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(5,189)	(1,657)	(6,266)	(1,147)
Total other comprehensive income (loss), net of tax	(1,699)	(5,282)	(622)	(5,792)
Ending balance	$ (6,888)	$ (6,939)	$ (6,888)	$ (6,939)