CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale (AFS) securities, tax effect	$ (21,694)	$ (7,884)	$ (476)	$ 5,193
Reclassification adjustment for net realized (gain) loss on AFS securities, tax effect	(2,547)	(1,609)	(3,574)	(1,701)
Adjustment to postretirement benefit plan obligation, tax effect	$ 508	$ 301	$ 1,016	$ 602