Net Income 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
Earnings Per Share, Diluted [Line Items]
Net income attributable to shareholders	$ 53,885	[1]	$ 134,630		$ 99,679	[2]	$ 113,768		$ 164,518	$ 117,727	$ 134,270	$ 106,235	$ 401,962		$ 522,750		$ 497,726
Weight-average shares outstanding - basic													88,681		90,960		94,608
Net effect of various dilutive stock-based compensation awards													1,085		1,073		1,078
Weighted average shares outstanding - diluted													89,766		92,033		95,686
Net Income per Share [Abstract]
Basic	$ 0.61	[3]	$ 1.52	[3]	$ 1.12	[3]	$ 1.27	[3]	$ 1.84	$ 1.29	$ 1.46	$ 1.16	$ 4.53		$ 5.75		$ 5.26
Diluted	$ 0.60	[3]	$ 1.50	[3]	$ 1.11	[3]	$ 1.26	[3]	$ 1.81	$ 1.28	$ 1.45	$ 1.14	$ 4.48	[4]	$ 5.68	[4]	$ 5.20	[4]
Stock Compensation Plan [Member]
Net Income per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount													380		766		658

[1] U.S. Tax Act expense of $124.7 million during the fourth quarter of 2017.

[2] a loss on extinguishment of debt of $58.8 million

[3] Quarterly net income per share is calculated using the weighted-average shares outstanding during each quarterly period, while net income per share for the full year is calculated using the weighted-average shares outstanding during the year. Therefore, the sum of the net income per share for each of the four quarters may not equal the net income per share for the full year.

[4] Stock-based compensation awards for the issuance of 380 shares, 766 shares, and 658 shares for the years ended December 31, 2017, 2016, and 2015, respectively, were excluded from the computation of net income per share on a diluted basis as their effect was anti-dilutive.