Condensed Consolidating Financial Information - Cash Flows (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 03, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		$ 62,756	$ 531,905	$ 856,556
Cash flows from investing activities:
Purchases of investments		(6,722)	(24)	(9)
Sales and maturities of investments		13,069	739	961
Proceeds from merger transaction				650,050
Cash paid for acquisitions of businesses, net of cash acquired		9,040	(22,278)	(80,187)
Capital expenditures		(574,467)	(395,455)	(867,106)
Proceeds from sales of assets and insurance claims		57,933	34,831	68,206
Other		(856)	64	1,081
Investment in unconsolidated affiliates				(445)
Net cash (used for) provided by investing activities		(502,003)	(382,123)	(227,449)
Cash flows from financing activities:
Increase (decrease) in cash overdrafts		(188)	3	645
Proceeds from issuance of long-term debt		411,200	600,000
Debt issuance costs		(11,043)	(11,520)	(1,847)
Proceeds from revolving credit facilities		725,000	611,500	3,972
Reduction in revolving credit facilities		(215,000)	(611,500)	(450,000)
Proceeds from (payments for) issuance of common shares		8,300	967	1,296
Purchase of capped call hedge transactions		(40,250)
Reduction of long-term debt		(381,814)	(493,612)	(27,478)
Dividends to shareholders	$ (17,100)	(68,503)	(50,924)	(69,363)
Proceeds from (payments for) commercial paper, net		40,000	(8,000)	(525,119)
Payments on term loan		(162,500)	(162,500)	(300,000)
Proceeds from (payments for) short-term borrowings		(543)	(6,211)	318
Cash proceeds from equity component of exchangeable debt		159,952
Noncontrolling interest contribution		20,000		3,972
Distributions to noncontrolling interest		7,272
Other changes		(8,211)	(4,732)	(7,767)
Proceeds from term loan				625,000
Repurchase of common shares		(18,071)	(1,687)	(99,598)
Redeemable noncontrolling interest contribution		61,123
Net cash (used for) provided by financing activities		512,180	(138,216)	(849,941)
Effect of exchange rate changes on cash and cash equivalents		(29)	(2,003)	(25,785)
Net increase (decrease) in cash and cash equivalents		72,904	9,563	(246,619)
Cash and cash equivalents, beginning of period		264,093	254,530	501,149
Cash and cash equivalents, end of period		336,997	264,093	254,530
Consolidating Adjustments
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		(132,986)	(50,423)	(31,263)
Cash flows from investing activities:
Cash paid for investments in consolidated affiliates			(245,459)
Investment in unconsolidated affiliates		86,060
Net cash (used for) provided by investing activities		86,060	245,459
Cash flows from financing activities:
Proceeds from parent contributions		(86,060)	245,458
Dividends to shareholders		11,916	8,942	9,941
Distribution from subsidiary to parent		121,070	41,480	21,322
Net cash (used for) provided by financing activities		46,926	(195,036)	31,263
Parent Company | Reportable Legal Entities
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		143,444	58,406	39,478
Cash flows from investing activities:
Proceeds from merger transaction				5,500
Investment in unconsolidated affiliates		(100)
Net cash (used for) provided by investing activities		(100)		5,500
Cash flows from financing activities:
Proceeds from (payments for) issuance of common shares		8,299	967	1,296
Dividends to shareholders		(80,419)	(59,866)	(79,304)
Proceeds from issuance of intercompany debt		57,000	45,500
Paydown of intercompany debt		(102,000)	(40,000)	(27,000)
Other changes		(8,210)	(4,732)	(7,767)
Repurchase of common shares		(18,071)
Proceeds (issuance) of intercompany debt				67,500
Net cash (used for) provided by financing activities		(143,401)	(58,131)	(45,275)
Net increase (decrease) in cash and cash equivalents		(57)	275	(297)
Cash and cash equivalents, beginning of period		1,148	873	1,170
Cash and cash equivalents, end of period		1,091	1,148	873
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		(90,229)	(233,738)	(217,685)
Cash flows from investing activities:
Proceeds from merger transaction				646,078
Cash paid for investments in consolidated affiliates			86,459
Change in intercompany balances		(599,974)	(103,384)	135,518
Net cash (used for) provided by investing activities		(599,974)	16,925	781,596
Cash flows from financing activities:
Proceeds from issuance of long-term debt		411,200	600,000
Debt issuance costs		(11,043)	(11,520)	(1,847)
Proceeds from revolving credit facilities		725,000	610,000
Reduction in revolving credit facilities		(215,000)	(610,000)	(450,000)
Proceeds from parent contributions		42,980	(159,000)
Purchase of capped call hedge transactions		(40,250)
Reduction of long-term debt		(270,269)	(350,000)
Proceeds from (payments for) commercial paper, net		40,000	(8,000)	(525,119)
Payments on term loan		(162,500)	(162,500)	(300,000)
Cash proceeds from equity component of exchangeable debt		159,952
Proceeds from issuance of intercompany debt		20,000
Paydown of intercompany debt		(20,000)
Proceeds from term loan				625,000
Proceeds (issuance) of intercompany debt				88,058
Net cash (used for) provided by financing activities		680,070	226,980	(563,908)
Net increase (decrease) in cash and cash equivalents		(10,133)	10,167	3
Cash and cash equivalents, beginning of period		10,177	10	7
Cash and cash equivalents, end of period		44	10,177	10
Other Subsidiaries (Non-Guarantors) | Reportable Legal Entities
Condensed Consolidating Statements Of Cash Flows
Net cash provided by (used for) operating activities		142,527	757,660	1,066,026
Cash flows from investing activities:
Purchases of investments		(6,722)	(24)	(9)
Sales and maturities of investments		13,069	739	961
Proceeds from merger transaction				(1,528)
Cash paid for acquisitions of businesses, net of cash acquired		9,040	(22,278)	(80,187)
Cash paid for investments in consolidated affiliates			159,000
Capital expenditures		(574,467)	(395,455)	(867,106)
Proceeds from sales of assets and insurance claims		57,933	34,831	68,206
Change in intercompany balances		599,974	103,384	(135,518)
Other		(856)	64	1,081
Investment in unconsolidated affiliates		(85,960)		(445)
Net cash (used for) provided by investing activities		12,011	(644,507)	(1,014,545)
Cash flows from financing activities:
Increase (decrease) in cash overdrafts		(188)	3	645
Proceeds from revolving credit facilities			1,500	3,972
Reduction in revolving credit facilities			(1,500)
Proceeds from parent contributions		43,080	(86,458)
Proceeds from (payments for) issuance of common shares		1
Reduction of long-term debt		(111,545)	(143,612)	(27,478)
Proceeds from (payments for) short-term borrowings		(543)	(6,211)	318
Proceeds from issuance of intercompany debt		(77,000)	(45,500)
Noncontrolling interest contribution		20,000
Paydown of intercompany debt		122,000	40,000	27,000
Distributions to noncontrolling interest		7,272
Distribution from subsidiary to parent		(121,070)	(41,480)	(21,322)
Other changes		(1)
Repurchase of common shares			(1,687)	(99,598)
Redeemable noncontrolling interest contribution		61,123
Proceeds (issuance) of intercompany debt				(155,558)
Net cash (used for) provided by financing activities		(71,415)	(112,029)	(272,021)
Effect of exchange rate changes on cash and cash equivalents		(29)	(2,003)	(25,785)
Net increase (decrease) in cash and cash equivalents		83,094	(879)	(246,325)
Cash and cash equivalents, beginning of period		252,768	253,647	499,972
Cash and cash equivalents, end of period		$ 335,862	$ 252,768	$ 253,647