Accumulated Other Comprehensive Loss - Before and After Tax Amounts for Comprehensive Income (Loss) Components (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss)	$ 6,048	$ 29,846
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss) before tax	(2,852)	22,553
Other comprehensive income/(loss), tax	0
Other comprehensive income/(loss)	(2,852)	22,553
Defined benefit pension items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss) before reclassifications before tax	(681)	(1,145)
Other comprehensive income/(loss) before reclassifications, tax	173	0
Other comprehensive income/(loss) before reclassifications, net of tax	(508)	(1,145)
Amounts reclassified from accumulated other comprehensive income/(loss) before tax	10,254	9,301
Amounts reclassified from accumulated other comprehensive income/(loss), tax	(2,590)	(2,339)
Amounts reclassified from accumulated other comprehensive income/(loss) net of tax	7,664	6,962
Other comprehensive income/(loss) before tax	9,573	8,156
Other comprehensive income/(loss), tax	(2,417)	(2,339)
Other comprehensive income/(loss)	7,156	5,817
Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss) before reclassifications before tax	3,022	1,475
Other comprehensive income/(loss) before reclassifications, tax	(766)	(293)
Other comprehensive income/(loss) before reclassifications, net of tax	2,256	1,182
Other comprehensive income/(loss) before tax	2,513	1,295
Other comprehensive income/(loss), tax	(649)	(248)
Other comprehensive income/(loss)	1,864	1,047
Gains and Losses on Cash Flow Hedges | Fixed Assets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income/(loss) before tax	(45)	45
Amounts reclassified from accumulated other comprehensive income/(loss), tax	0	0
Amounts reclassified from accumulated other comprehensive income/(loss) net of tax	(45)	45
Gains and Losses on Cash Flow Hedges | Net Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income/(loss) before tax	(464)	(225)
Amounts reclassified from accumulated other comprehensive income/(loss), tax	117	45
Amounts reclassified from accumulated other comprehensive income/(loss) net of tax	(347)	(180)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income/(loss) before tax	9,234	32,004
Other comprehensive income/(loss), tax	(3,066)	(2,587)
Other comprehensive income/(loss)	$ 6,168	$ 29,417