Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 27, 2015	Sep. 25, 2016
NET CASH PROVIDED BY OPERATING ACTIVITIES	$ 39,205	$ 39,261
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to property, plant and equipment	(32,629)	(30,165)
Proceeds from sales and maturities of investments	3,750	200
Purchase of investments	(950)	0
Proceeds from sale of property, plant and equipment	1,815	1
Other	(18)	0
NET CASH USED IN INVESTING ACTIVITIES	(28,032)	(29,964)
CASH FLOWS FROM FINANCING ACTIVITIES:
Cash dividends paid	(14,371)	(13,783)
Payments for Repurchase of Common Stock	(14,374)	(13,527)
Proceeds from Stock Options Exercised	7,265	1,616
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES	(21,480)	(25,694)
Effect of exchange rate changes on cash	(2,196)	162
Net decrease in cash and cash equivalents	(12,503)	(16,235)
Cash and cash equivalents at the beginning of the period	$ 49,948	52,036
Cash and cash equivalents at the end of period		$ 35,801