Financial Instruments Measured at Fair Value - Fair Value Hierarchy (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized Gain on Securities		$ 14	$ 378		$ 2,220
Unrealized Loss on Securities				$ (4,993)
Equity Method Investment, Ownership Percentage		8.40%		8.40%
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents		$ 15,740		$ 15,740		$ 18,579
Equity investments		39,887		39,887		44,677
Interest rate swaps designated as cash flow hedges - asset		4,797		4,797
Interest rate swaps designated as cash flow hedges - liability		(494)		(494)		(11,574)
Foreign exchange contracts designated as net investment hedges		33,495		33,495		21,718
Total Fair Value Assets And Liabilities Measured On Recurring Basis		93,425		93,425		73,400
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]	15,740		15,740		18,579
Equity investments	[2]	39,887		39,887		44,677
Interest rate swaps designated as cash flow hedges - asset		0		0
Interest rate swaps designated as cash flow hedges - liability		0		0		0
Foreign exchange contracts designated as net investment hedges		0		0		0
Total Fair Value Assets And Liabilities Measured On Recurring Basis		55,627		55,627		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 designated as cash flow hedges - asset		4,797		4,797
Interest rate swaps designated as cash flow hedges - liability		(494)		(494)		(11,574)
Foreign exchange contracts designated as net investment hedges		33,495		33,495		21,718
Total Fair Value Assets And Liabilities Measured On Recurring Basis		37,798		37,798		10,144
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 designated as cash flow hedges - asset		0		0
Interest rate swaps designated as cash flow hedges - liability		0		0		0
Foreign exchange contracts designated as net investment hedges		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 $14 and an unrealized loss of $4,993 for the third quarter and first nine months of 2020, respectively, on equity securities held at the end of the quarter. The company recorded an unrealized gain of $378 and $2,220 for the third quarter and first nine months of 2019, respectively, on equity securities held at the end of the quarter.