Summary of Significant Accounting Policies (Computations Of Basic And Diluted Earnings (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Oct. 01, 2016	Jul. 02, 2016	Apr. 02, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Net income	$ 240,378	$ 270,025	$ 260,681	$ 200,554	$ 233,748	$ 269,878	$ 255,188	$ 171,548	$ 971,638	$ 930,362	$ 615,302
Accretion of redeemable noncontrolling interest									(46)	(123)	(194)
Net earnings available to common stockholders									$ 971,592	$ 930,239	$ 615,108
Weighted-average common shares outstanding-basic (in shares)									74,357	74,104	73,516
Add weighted-average dilutive potential common shares - options and RSU’s to purchase common shares, net (in shares)									482	464	527
Weighted-average common shares outstanding-diluted (in shares)									74,839	74,568	74,043
Basic earnings per share (usd per share)	$ 3.23	$ 3.63	$ 3.51	$ 2.70	$ 3.15	$ 3.64	$ 3.44	$ 2.32	$ 13.07	$ 12.55	$ 8.37
Diluted earnings per share (usd per share)	$ 3.21	$ 3.61	$ 3.48	$ 2.68	$ 3.13	$ 3.62	$ 3.42	$ 2.30	$ 12.98	$ 12.48	$ 8.31