Condensed Consolidating Financial Information - Cash Flows (Details) - USD ($) $ in Thousands		3 Months Ended
	Apr. 03, 2018	Mar. 31, 2018	Mar. 31, 2017
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		$ (81,683)	$ (57,991)
Cash flows from investing activities:
Purchases of investments		(676)	(4)
Sales and maturities of investments		1,148	91
Capital expenditures		(94,026)	(183,427)
Proceeds from sales of assets and insurance claims		3,076	3,253
Other		1,034	(106)
Net cash (used for) provided by investing activities		(89,444)	(180,193)
Cash flows from financing activities:
Increase (decrease) in cash overdrafts		(383)	(469)
Proceeds from issuance of long-term debt		800,000	411,200
Debt issuance costs		(12,928)	(10,439)
Proceeds from revolving credit facilities		615,000
Reduction in revolving credit facilities		(680,000)
Proceeds from (payments for) issuance of common shares			8,300
Purchase of capped call hedge transactions			(40,250)
Reduction of long-term debt		(460,837)	(170,491)
Dividends to shareholders	$ (19,100)	(17,148)	(17,040)
Proceeds from (payments for) commercial paper, net		(40,000)
Payments on term loan			(162,500)
Proceeds from (payments for) short-term borrowings		194	16
Cash proceeds from equity component of exchangeable debt			159,952
Other changes		(1,862)	(5,341)
Net cash (used for) provided by financing activities		202,036	172,938
Effect of exchange rate changes on cash and cash equivalents		(867)	1,841
Net increase (decrease) in cash and cash equivalents		30,042	(63,405)
Cash and cash equivalents, beginning of period		336,997	264,093
Cash and cash equivalents, end of period		367,039	200,688
Consolidating Adjustments
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		(24,981)	(69,980)
Cash flows from financing activities:
Dividends to shareholders		2,981	2,980
Distribution from subsidiary to parent		22,000	67,000
Net cash (used for) provided by financing activities		24,981	69,980
Parent Company | Reportable Legal Entities
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		22,374	70,492
Cash flows from financing activities:
Proceeds from (payments for) issuance of common shares			8,300
Dividends to shareholders		(20,129)	(20,020)
Proceeds from issuance of intercompany debt		20,000	20,000
Paydown of intercompany debt		(21,000)	(66,000)
Other changes		(1,862)	(5,341)
Net cash (used for) provided by financing activities		(22,991)	(63,061)
Net increase (decrease) in cash and cash equivalents		(617)	7,431
Cash and cash equivalents, beginning of period		1,091	1,148
Cash and cash equivalents, end of period		474	8,579
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		(98,371)	(112,431)
Cash flows from investing activities:
Change in intercompany balances		(122,864)	(198,035)
Net cash (used for) provided by investing activities		(122,864)	(198,035)
Cash flows from financing activities:
Proceeds from issuance of long-term debt		800,000	411,200
Debt issuance costs		(12,928)	(10,439)
Proceeds from revolving credit facilities		615,000
Reduction in revolving credit facilities		(680,000)
Purchase of capped call hedge transactions			(40,250)
Reduction of long-term debt		(460,837)	(57,670)
Proceeds from (payments for) commercial paper, net		(40,000)
Payments on term loan			(162,500)
Cash proceeds from equity component of exchangeable debt			159,952
Proceeds from issuance of intercompany debt			20,000
Paydown of intercompany debt			(20,000)
Net cash (used for) provided by financing activities		221,235	300,293
Net increase (decrease) in cash and cash equivalents			(10,173)
Cash and cash equivalents, beginning of period		44	10,177
Cash and cash equivalents, end of period		44	4
Other Subsidiaries (Non-Guarantors) | Reportable Legal Entities
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		19,295	53,928
Cash flows from investing activities:
Purchases of investments		(676)	(4)
Sales and maturities of investments		1,148	91
Capital expenditures		(94,026)	(183,427)
Proceeds from sales of assets and insurance claims		3,076	3,253
Change in intercompany balances		122,864	198,035
Other		1,034	(106)
Net cash (used for) provided by investing activities		33,420	17,842
Cash flows from financing activities:
Increase (decrease) in cash overdrafts		(383)	(469)
Reduction of long-term debt			(112,821)
Proceeds from (payments for) short-term borrowings		194	16
Proceeds from issuance of intercompany debt		(20,000)	(40,000)
Paydown of intercompany debt		21,000	86,000
Distribution from subsidiary to parent		(22,000)	(67,000)
Net cash (used for) provided by financing activities		(21,189)	(134,274)
Effect of exchange rate changes on cash and cash equivalents		(867)	1,841
Net increase (decrease) in cash and cash equivalents		30,659	(60,663)
Cash and cash equivalents, beginning of period		335,862	252,768
Cash and cash equivalents, end of period		$ 366,521	$ 192,105