Condensed consolidating guarantor financial information - Income and Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Consolidated Guarantor Financial Information [Abstract]
Noncontrolling interest percent	100.00%								100.00%
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Net revenues	$ 641,615	$ 609,672	$ 609,866	$ 587,230	$ 595,106	$ 534,703	$ 528,613	$ 487,881	$ 2,448,383	$ 2,146,303	$ 1,868,027
Cost of goods sold									1,063,941	974,501	871,827
Gross profit	365,821	342,573	344,778	331,270	330,731	295,227	290,284	255,560	1,384,442	1,171,802	996,200
Selling, general and administrative expenses									878,688	699,963	563,308
Research and development expenses									106,208	84,770	58,579
Restructuring and impairment charges									79,230	14,790	59,227
Gain on sale of assets									(1,388)	0	(4,367)
Income from continuing operations before interest, loss on extinguishment of debt and taxes	119,266	82,105	33,490	86,843	90,904	110,354	110,202	60,819	321,704	372,279	319,453
Interest, net									102,076	81,775	54,467
Loss on extinguishment of debt									0	5,593	19,261
Income from continuing operations before taxes									219,628	284,911	245,725
(Benefit) taxes on (loss) income from continuing operations									23,196	129,648	8,074
Equity in net income of consolidated subsidiaries									0	0	0
Income from continuing operations	87,513	56,540	(2,552)	54,931	(42,847)	79,398	78,363	40,349	196,432	155,263	237,651
Operating income from discontinued operations									5,643	(4,534)	(922)
Tax on income from discontinued operations									1,273	(1,801)	(1,112)
Income (loss) on discontinued operations	3,077	(16)	56	1,253	189	(2,383)	(360)	(179)	4,370	(2,733)	190
Net income	90,590	56,524	(2,496)	56,184	(42,658)	77,015	78,003	40,170	200,802	152,530	237,841
Less: Income from continuing operations attributable to noncontrolling interest									0	0	464
Net income	$ 90,590	$ 56,524	$ (2,496)	$ 56,184	$ (42,658)	$ 77,015	$ 78,003	$ 40,170	200,802	152,530	237,377
Other comprehensive loss									(75,994)	173,626	(66,761)
Comprehensive income									124,808	326,156	170,616
Eliminations
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Net revenues									(424,211)	(399,093)	(369,395)
Cost of goods sold									(419,205)	(398,179)	(368,725)
Gross profit									(5,006)	(914)	(670)
Selling, general and administrative expenses									(671)	196	(473)
Research and development expenses									0	0	0
Restructuring and impairment charges									0	0	0
Gain on sale of assets									0		0
Income from continuing operations before interest, loss on extinguishment of debt and taxes									(4,335)	(1,110)	(197)
Interest, net									0	0	0
Loss on extinguishment of debt										0	0
Income from continuing operations before taxes									(4,335)	(1,110)	(197)
(Benefit) taxes on (loss) income from continuing operations									(235)	(484)	(81)
Equity in net income of consolidated subsidiaries									(512,927)	(220,092)	(559,911)
Income from continuing operations									(517,027)	(220,718)	(560,027)
Operating income from discontinued operations									0	0	0
Tax on income from discontinued operations									0	0	0
Income (loss) on discontinued operations									0	0	0
Net income									(517,027)	(220,718)	(560,027)
Less: Income from continuing operations attributable to noncontrolling interest											0
Net income											(560,027)
Other comprehensive loss									160,542	(356,943)	156,798
Comprehensive income									(356,485)	(577,661)	(403,229)
Parent Company
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Net revenues									0	0	0
Cost of goods sold									0	0	0
Gross profit									0	0	0
Selling, general and administrative expenses									50,866	47,412	43,602
Research and development expenses									1,482	1,009	547
Restructuring and impairment charges									0	0	173
Gain on sale of assets									0		(2,707)
Income from continuing operations before interest, loss on extinguishment of debt and taxes									(52,348)	(48,421)	(41,615)
Interest, net									95,173	99,371	61,374
Loss on extinguishment of debt										5,593	19,261
Income from continuing operations before taxes									(147,521)	(153,385)	(122,250)
(Benefit) taxes on (loss) income from continuing operations									(53,401)	(110,921)	(44,674)
Equity in net income of consolidated subsidiaries									291,572	197,727	315,396
Income from continuing operations									197,452	155,263	237,820
Operating income from discontinued operations									4,363	(4,534)	(1,300)
Tax on income from discontinued operations									1,013	(1,801)	(857)
Income (loss) on discontinued operations									3,350	(2,733)	(443)
Net income									200,802	152,530	237,377
Less: Income from continuing operations attributable to noncontrolling interest											0
Net income											237,377
Other comprehensive loss									(75,994)	173,626	(66,761)
Comprehensive income									124,808	326,156	170,616
Guarantor Subsidiaries
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Net revenues									1,584,650	1,368,149	1,112,464
Cost of goods sold									886,161	778,153	652,442
Gross profit									698,489	589,996	460,022
Selling, general and administrative expenses									514,598	408,811	328,263
Research and development expenses									73,067	57,614	33,080
Restructuring and impairment charges									20,639	8,971	50,183
Gain on sale of assets									(1,388)		(155)
Income from continuing operations before interest, loss on extinguishment of debt and taxes									91,573	114,600	48,651
Interest, net									4,796	(21,153)	(11,009)
Loss on extinguishment of debt										0	0
Income from continuing operations before taxes									86,777	135,753	59,660
(Benefit) taxes on (loss) income from continuing operations									34,591	(20,333)	12,954
Equity in net income of consolidated subsidiaries									220,718	25,500	243,987
Income from continuing operations									272,904	181,586	290,693
Operating income from discontinued operations									0	0	0
Tax on income from discontinued operations									0	0	0
Income (loss) on discontinued operations									0	0	0
Net income									272,904	181,586	290,693
Less: Income from continuing operations attributable to noncontrolling interest											0
Net income											290,693
Other comprehensive loss									(80,030)	158,490	(76,098)
Comprehensive income									192,874	340,076	214,595
Non-Guarantor Subsidiaries
Schedule Of Condensed Consolidating Statement Of Operations [Line Items]
Net revenues									1,287,944	1,177,247	1,124,958
Cost of goods sold									596,985	594,527	588,110
Gross profit									690,959	582,720	536,848
Selling, general and administrative expenses									313,895	243,544	191,916
Research and development expenses									31,659	26,147	24,952
Restructuring and impairment charges									58,591	5,819	8,871
Gain on sale of assets									0		(1,505)
Income from continuing operations before interest, loss on extinguishment of debt and taxes									286,814	307,210	312,614
Interest, net									2,107	3,557	4,102
Loss on extinguishment of debt										0	0
Income from continuing operations before taxes									284,707	303,653	308,512
(Benefit) taxes on (loss) income from continuing operations									42,241	261,386	39,875
Equity in net income of consolidated subsidiaries									637	(3,135)	528
Income from continuing operations									243,103	39,132	269,165
Operating income from discontinued operations									1,280	0	378
Tax on income from discontinued operations									260	0	(255)
Income (loss) on discontinued operations									1,020	0	633
Net income									244,123	39,132	269,798
Less: Income from continuing operations attributable to noncontrolling interest											464
Net income											269,334
Other comprehensive loss									(80,512)	198,453	(80,700)
Comprehensive income									$ 163,611	$ 237,585	$ 188,634