Condensed consolidating guarantor financial information - Balance Sheets (Details) - USD ($) $ in Thousands	Jul. 02, 2017	Dec. 31, 2016	Jun. 26, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 676,214	$ 543,789	$ 476,490	$ 338,366
Accounts receivable, net	303,702	271,993
Accounts receivable from consolidated subsidiaries	0	0
Inventories, net	368,526	316,171
Prepaid expenses and other current assets	47,298	40,382
Prepaid taxes	11,878	8,179
Assets held for sale	0	2,879
Total current assets	1,407,618	1,183,393
Property, plant and equipment, net	369,301	302,899
Goodwill	1,854,076	1,276,720
Intangible assets, net	1,612,904	1,091,663
Deferred tax assets	1,963	1,712
Notes receivable and other amounts due from consolidated subsidiaries	0	0
Other assets	44,162	34,826
Total assets	5,290,024	3,891,213
Current liabilities
Current borrowings	112,039	183,071
Accounts payable	81,973	69,400
Accounts payable to consolidated subsidiaries	0	0
Accrued expenses	85,050	65,149
Current portion of contingent consideration	584	587
Payroll and benefit-related liabilities	78,951	82,679
Accrued interest	5,294	10,450
Income taxes payable	3,438	7,908
Other current liabilities	8,722	8,402
Total current liabilities	376,051	427,646
Long-term borrowings	1,887,716	850,252
Deferred tax liabilities	468,034	271,377
Pension and postretirement benefit liabilities	128,335	133,062
Noncurrent liability for uncertain tax positions	18,378	17,520
Notes payable and other amounts due to consolidated subsidiaries	0	0
Other liabilities	52,981	52,015
Total liabilities	2,931,495	1,751,872
Convertible notes - redeemable equity component	0	1,824
Mezzanine equity	0	1,824
Total shareholders' equity	2,358,529	2,137,517
Total liabilities and shareholders' equity	5,290,024	3,891,213
Reportable Legal Entities | Parent Company
Current assets
Cash and cash equivalents	56,699	14,571	50,209	21,612
Accounts receivable, net	2,236	2,551
Accounts receivable from consolidated subsidiaries	8,333	4,861
Inventories, net	0	0
Prepaid expenses and other current assets	14,163	14,239
Prepaid taxes	4,490	0
Assets held for sale		0
Total current assets	85,921	36,222
Property, plant and equipment, net	2,398	2,566
Goodwill	0	0
Intangible assets, net	0	0
Deferred tax assets	72,037	73,051
Notes receivable and other amounts due from consolidated subsidiaries	1,310,464	1,387,615
Other assets	7,386,675	6,044,337
Total assets	8,857,495	7,543,791
Current liabilities
Current borrowings	62,039	133,071
Accounts payable	3,136	4,540
Accounts payable to consolidated subsidiaries	2,306,666	2,242,814
Accrued expenses	19,284	16,827
Current portion of contingent consideration	0	0
Payroll and benefit-related liabilities	17,855	20,610
Accrued interest	5,264	10,429
Income taxes payable	0	1,246
Other current liabilities	500	2,262
Total current liabilities	2,414,744	2,431,799
Long-term borrowings	1,887,716	850,252
Deferred tax liabilities	0	0
Pension and postretirement benefit liabilities	80,154	85,645
Noncurrent liability for uncertain tax positions	1,729	1,169
Notes payable and other amounts due to consolidated subsidiaries	2,089,600	2,011,737
Other liabilities	25,023	23,848
Total liabilities	6,498,966	5,404,450
Convertible notes - redeemable equity component		1,824
Mezzanine equity		1,824
Total shareholders' equity	2,358,529	2,137,517
Total liabilities and shareholders' equity	8,857,495	7,543,791
Reportable Legal Entities | Guarantor Subsidiaries
Current assets
Cash and cash equivalents	10,963	1,031	1,089	0
Accounts receivable, net	34,592	8,768
Accounts receivable from consolidated subsidiaries	2,265,552	2,176,059
Inventories, net	228,022	200,852
Prepaid expenses and other current assets	9,280	5,332
Prepaid taxes	0	0
Assets held for sale		0
Total current assets	2,548,409	2,392,042
Property, plant and equipment, net	212,907	163,847
Goodwill	1,238,551	708,546
Intangible assets, net	1,152,095	640,999
Deferred tax assets	0	0
Notes receivable and other amounts due from consolidated subsidiaries	2,163,757	2,085,538
Other assets	1,706,244	1,525,285
Total assets	9,021,963	7,516,257
Current liabilities
Current borrowings	0	0
Accounts payable	38,529	30,924
Accounts payable to consolidated subsidiaries	261,263	214,203
Accrued expenses	26,593	18,126
Current portion of contingent consideration	584	587
Payroll and benefit-related liabilities	26,071	26,672
Accrued interest	0	0
Income taxes payable	0	0
Other current liabilities	4,250	3,643
Total current liabilities	357,290	294,155
Long-term borrowings	0	0
Deferred tax liabilities	508,629	316,526
Pension and postretirement benefit liabilities	31,026	31,561
Noncurrent liability for uncertain tax positions	13,781	13,684
Notes payable and other amounts due to consolidated subsidiaries	1,185,791	1,264,004
Other liabilities	13,961	15,695
Total liabilities	2,110,478	1,935,625
Convertible notes - redeemable equity component		0
Mezzanine equity		0
Total shareholders' equity	6,911,485	5,580,632
Total liabilities and shareholders' equity	9,021,963	7,516,257
Reportable Legal Entities | Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	608,552	528,187	425,192	316,754
Accounts receivable, net	262,539	255,815
Accounts receivable from consolidated subsidiaries	345,901	309,149
Inventories, net	168,954	140,406
Prepaid expenses and other current assets	20,518	17,474
Prepaid taxes	7,760	7,766
Assets held for sale		2,879
Total current assets	1,414,224	1,261,676
Property, plant and equipment, net	153,996	136,486
Goodwill	615,525	568,174
Intangible assets, net	460,809	450,664
Deferred tax assets	5,435	5,185
Notes receivable and other amounts due from consolidated subsidiaries	0	0
Other assets	31,051	29,962
Total assets	2,681,040	2,452,147
Current liabilities
Current borrowings	50,000	50,000
Accounts payable	40,308	33,936
Accounts payable to consolidated subsidiaries	51,857	33,052
Accrued expenses	39,173	30,196
Current portion of contingent consideration	0	0
Payroll and benefit-related liabilities	35,025	35,397
Accrued interest	30	21
Income taxes payable	4,408	6,577
Other current liabilities	3,972	2,497
Total current liabilities	224,773	191,676
Long-term borrowings	0	0
Deferred tax liabilities	34,914	31,375
Pension and postretirement benefit liabilities	17,155	15,856
Noncurrent liability for uncertain tax positions	2,868	2,667
Notes payable and other amounts due to consolidated subsidiaries	198,830	197,412
Other liabilities	13,997	12,472
Total liabilities	492,537	451,458
Convertible notes - redeemable equity component		0
Mezzanine equity		0
Total shareholders' equity	2,188,503	2,000,689
Total liabilities and shareholders' equity	2,681,040	2,452,147
Eliminations
Current assets
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	4,335	4,859
Accounts receivable from consolidated subsidiaries	(2,619,786)	(2,490,069)
Inventories, net	(28,450)	(25,087)
Prepaid expenses and other current assets	3,337	3,337
Prepaid taxes	(372)	413
Assets held for sale		0
Total current assets	(2,640,936)	(2,506,547)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Deferred tax assets	(75,509)	(76,524)
Notes receivable and other amounts due from consolidated subsidiaries	(3,474,221)	(3,473,153)
Other assets	(9,079,808)	(7,564,758)
Total assets	(15,270,474)	(13,620,982)
Current liabilities
Current borrowings	0	0
Accounts payable	0	0
Accounts payable to consolidated subsidiaries	(2,619,786)	(2,490,069)
Accrued expenses	0	0
Current portion of contingent consideration	0	0
Payroll and benefit-related liabilities	0	0
Accrued interest	0	0
Income taxes payable	(970)	85
Other current liabilities	0	0
Total current liabilities	(2,620,756)	(2,489,984)
Long-term borrowings	0	0
Deferred tax liabilities	(75,509)	(76,524)
Pension and postretirement benefit liabilities	0	0
Noncurrent liability for uncertain tax positions	0	0
Notes payable and other amounts due to consolidated subsidiaries	(3,474,221)	(3,473,153)
Other liabilities	0	0
Total liabilities	(6,170,486)	(6,039,661)
Convertible notes - redeemable equity component		0
Mezzanine equity		0
Total shareholders' equity	(9,099,988)	(7,581,321)
Total liabilities and shareholders' equity	$ (15,270,474)	$ (13,620,982)