Financial Instruments Measured at Fair Value - Fair Value Hierarchy (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized Gain on Securities		$ 4,964	$ 8		$ 1,842
Unrealized Loss on Securities				$ (5,031)
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents		21,480		21,480		$ 18,579
Equity investments		37,903		37,903		44,677
Interest rate swaps - asset		558		558
Interest rate swaps- liability		(3,029)		(3,029)		(11,574)
Foreign exchange contracts - asset		47,867		47,867		24,092
Foreign exchange contracts - liability		(2,595)		(2,595)		(2,132)
Total Fair Value Assets And Liabilities Measured On Recurring Basis		102,184		102,184		73,642
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	[1]	21,480		21,480		18,579
Equity investments	[2]	37,903		37,903		44,677
Interest rate swaps - asset		0		0
Interest rate swaps- liability		0		0		0
Foreign exchange contracts - asset		0		0		0
Foreign exchange contracts - liability		0		0		0
Total Fair Value Assets And Liabilities Measured On Recurring Basis		59,383		59,383		63,256
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents		0		0		0
Equity investments		0		0		0
Interest rate swaps - asset		558		558
Interest rate swaps- liability		(3,029)		(3,029)		(11,574)
Foreign exchange contracts - asset		47,867		47,867		24,092
Foreign exchange contracts - liability		(2,595)		(2,595)		(2,132)
Total Fair Value Assets And Liabilities Measured On Recurring Basis		42,801		42,801		10,386
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents		0		0		0
Equity investments		0		0		0
Interest rate swaps - asset		0		0
Interest rate swaps- liability		0		0		0
Foreign exchange contracts - asset		0		0		0
Foreign exchange contracts - liability		0		0		0
Total Fair Value Assets And Liabilities Measured On Recurring Basis		$ 0		$ 0		$ 0

[1] Cash equivalents include highly liquid investments with an original maturity of less than three months.

[2] The company has an 8.4% equity ownership interest in Marubun Corporation and a portfolio of mutual funds with quoted market prices. The company recorded an unrealized gain of $4,964 and an unrealized loss of $5,031 for the second quarter and first six months of 2020, respectively, on equity securities held at the end of the quarter. The company recorded an unrealized gain of $8 and $1,842 for the second quarter and first six months of 2019, respectively, on equity securities held at the end of the quarter.