Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 30, 2018	Dec. 31, 2017	Jan. 01, 2017
Quarterly Financial Data Table [Abstract]
Revenues	$ 397,820	$ 400,550	$ 411,002	$ 380,564	$ 309,247	$ 308,000	$ 320,342	$ 285,819	$ 1,589,936	$ 1,223,408	$ 1,435,418
Cost of sales	138,867	139,348	138,154	132,219	129,180	133,631	130,581	124,543	548,588	517,935	752,079
Operating profit	45,799	77,348	71,483	55,262	66,587	61,657	25,794	60,720	249,892	214,758	314,780
Net Income (loss)	$ 18,831	$ 391,249	$ 29,876	$ 20,159	$ 159,276	$ 14,257	$ (1,845)	$ 22,341	$ 460,115	$ 194,029	$ 129,624
Basic income (loss) per share
Basic income (loss) per share	$ 0.08	$ 1.65	$ 0.13	$ 0.08	$ 0.66	$ 0.06	$ (0.01)	$ 0.09	$ 1.93	$ 0.79	$ 0.49
Diluted income (loss) per share
Diluted income (loss) per share	$ 0.08	$ 1.60	$ 0.12	$ 0.08	$ 0.64	$ 0.06	$ (0.01)	$ 0.09	$ 1.88	$ 0.77	$ 0.49
Investment Income, Net		$ 450,133							$ 450,736	$ 2,703	$ 723
Reorganization and realignment costs	$ 2,377	$ 941	$ 3,124	$ 2,626	$ 1,806	$ 2,888	$ 17,699		9,068	22,574	10,083
System optimization (losses) gains, net							$ (41,050)		463	(39,076)	71,931
Income tax benefit (provision)					$ 121,649				$ (114,801)	$ 93,010	$ (72,066)