Condensed consolidating guarantor financial information - Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jul. 02, 2017	Jun. 26, 2016
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities from continuing operations	$ 197,690	$ 181,488
Cash flows from investing activities of continuing operations:
Expenditures for property, plant and equipment	(36,833)	(19,535)
Proceeds from sale of assets	6,332	3,985
Payments for businesses and intangibles acquired, net of cash acquired	(993,459)	(3,117)
Net cash used in investing activities from continuing operations	(1,023,960)	(18,667)
Cash flows from financing activities of continuing operations:
Proceeds from new borrowings	1,194,500	665,000
Reduction in borrowings	(228,273)	(656,479)
Debt extinguishment, issuance and amendment fees	(19,114)	(8,182)
Net proceeds from share based compensation plans and the related tax impacts	1,305	6,593
Payments for contingent consideration	(153)	(133)
Dividends paid	(30,590)	(28,998)
Intercompany transactions	0	0
Intercompany dividends paid	0
Net cash provided by (used in) financing activities from continuing operations	917,675	(22,199)
Cash flows from discontinued operations:
Net cash used in operating activities	(961)	(1,183)
Net cash used in discontinued operations	(961)	(1,183)
Effect of exchange rate changes on cash and cash equivalents	41,981	(1,315)
Net increase in cash and cash equivalents	132,425	138,124
Cash and cash equivalents at the beginning of the period	543,789	338,366
Cash and cash equivalents at the end of the period	676,214	476,490
Reportable Legal Entities | Parent Company
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities from continuing operations	(121,726)	(29,648)
Cash flows from investing activities of continuing operations:
Expenditures for property, plant and equipment	(173)	(146)
Proceeds from sale of assets	0	0
Payments for businesses and intangibles acquired, net of cash acquired	(975,524)	0
Net cash used in investing activities from continuing operations	(975,697)	(146)
Cash flows from financing activities of continuing operations:
Proceeds from new borrowings	1,194,500	665,000
Reduction in borrowings	(228,273)	(656,479)
Debt extinguishment, issuance and amendment fees	(19,114)	(8,182)
Net proceeds from share based compensation plans and the related tax impacts	1,305	6,593
Payments for contingent consideration	0	0
Dividends paid	(30,590)	(28,998)
Intercompany transactions	222,684	81,640
Intercompany dividends paid	0
Net cash provided by (used in) financing activities from continuing operations	1,140,512	59,574
Cash flows from discontinued operations:
Net cash used in operating activities	(961)	(1,183)
Net cash used in discontinued operations	(961)	(1,183)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	42,128	28,597
Cash and cash equivalents at the beginning of the period	14,571	21,612
Cash and cash equivalents at the end of the period	56,699	50,209
Reportable Legal Entities | Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities from continuing operations	232,874	69,875
Cash flows from investing activities of continuing operations:
Expenditures for property, plant and equipment	(19,760)	(9,947)
Proceeds from sale of assets	0	20,642
Payments for businesses and intangibles acquired, net of cash acquired	0	0
Net cash used in investing activities from continuing operations	(19,760)	10,695
Cash flows from financing activities of continuing operations:
Proceeds from new borrowings	0	0
Reduction in borrowings	0	0
Debt extinguishment, issuance and amendment fees	0	0
Net proceeds from share based compensation plans and the related tax impacts	0	0
Payments for contingent consideration	(153)	(133)
Dividends paid	0	0
Intercompany transactions	(203,029)	(79,348)
Intercompany dividends paid	0
Net cash provided by (used in) financing activities from continuing operations	(203,182)	(79,481)
Cash flows from discontinued operations:
Net cash used in operating activities	0	0
Net cash used in discontinued operations	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase in cash and cash equivalents	9,932	1,089
Cash and cash equivalents at the beginning of the period	1,031	0
Cash and cash equivalents at the end of the period	10,963	1,089
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities from continuing operations	148,460	141,261
Cash flows from investing activities of continuing operations:
Expenditures for property, plant and equipment	(16,900)	(9,442)
Proceeds from sale of assets	6,332	1,251
Payments for businesses and intangibles acquired, net of cash acquired	(17,935)	(21,025)
Net cash used in investing activities from continuing operations	(28,503)	(29,216)
Cash flows from financing activities of continuing operations:
Proceeds from new borrowings	0	0
Reduction in borrowings	0	0
Debt extinguishment, issuance and amendment fees	0	0
Net proceeds from share based compensation plans and the related tax impacts	0	0
Payments for contingent consideration	0	0
Dividends paid	0	0
Intercompany transactions	(19,655)	(2,292)
Intercompany dividends paid	(61,918)
Net cash provided by (used in) financing activities from continuing operations	(81,573)	(2,292)
Cash flows from discontinued operations:
Net cash used in operating activities	0	0
Net cash used in discontinued operations	0	0
Effect of exchange rate changes on cash and cash equivalents	41,981	(1,315)
Net increase in cash and cash equivalents	80,365	108,438
Cash and cash equivalents at the beginning of the period	528,187	316,754
Cash and cash equivalents at the end of the period	608,552	425,192
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities from continuing operations	(61,918)	0
Cash flows from investing activities of continuing operations:
Expenditures for property, plant and equipment	0	0
Proceeds from sale of assets	0	(17,908)
Payments for businesses and intangibles acquired, net of cash acquired	0	17,908
Net cash used in investing activities from continuing operations	0	0
Cash flows from financing activities of continuing operations:
Proceeds from new borrowings	0	0
Reduction in borrowings	0	0
Debt extinguishment, issuance and amendment fees	0	0
Net proceeds from share based compensation plans and the related tax impacts	0	0
Payments for contingent consideration	0	0
Dividends paid	0	0
Intercompany transactions	0	0
Intercompany dividends paid	61,918
Net cash provided by (used in) financing activities from continuing operations	61,918	0
Cash flows from discontinued operations:
Net cash used in operating activities	0	0
Net cash used in discontinued operations	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase in cash and cash equivalents		0
Cash and cash equivalents at the beginning of the period	0	0
Cash and cash equivalents at the end of the period	$ 0	$ 0