Accumulated Other Comprehensive Income (Reclassifications out of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Investment income	$ 977	$ 1,057
Provision for income taxes	(11,764)	(11,461)
Total amount reclassified, net of tax	20,129	20,026
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Investment income	47	3
Provision for income taxes	(21)	(1)
Total amount reclassified, net of tax	$ 26	$ 2