Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Net income	$ 42,808	$ 30,802	$ 130,338	$ 77,243
Other comprehensive income (loss):
Pension liability adjustments (net of tax of $89 and $30 for the three months ended 2017 and 2016, and $144 and $395 for the nine months ended 2017 and 2016, respectively)	58	(138)	(142)	(183)
Pension and post-retirement reclassification adjustments	(118)	68	(299)	212
Unrealized (loss) gain on investments	(1,710)	927	(1,235)	(559)
Foreign currency translation adjustments	1,531	(5,771)	2,912	(8,951)
Comprehensive income	$ 42,569	$ 25,888	$ 131,574	$ 67,762