CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Net income	$ 119,981	$ 103,420	$ 307,991	$ 363,616
Other comprehensive income, net of tax:
Foreign currency translation adjustment	7,213	9,291	(11,568)	34,235
Available-for-sale marketable securities:
Unrealized gains (losses) on marketable securities arising during period, net of tax of $(62), $481, $(806), $1,666, respectively	(66)	950	(2,555)	2,448
Less: Reclassification adjustment for (gains) losses included in net income, net of tax of $(17), $(67), $(6), $(173), respectively	(57)	(87)	1,411	(264)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Total	(123)	863	(1,144)	2,184
Defined benefit pension and post-retirement plans:
Amortization of prior service benefit included in net periodic pension and post-retirement benefit, net of tax of $(18), $(38), $(53), $(115), respectively	(61)	(68)	(184)	(204)
Other comprehensive income (loss)	7,029	10,086	(12,896)	36,215
Comprehensive income	$ 127,010	$ 113,506	$ 295,095	$ 399,831