Condensed consolidating guarantor financial information - Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 357,161	$ 333,558	$ 543,789	$ 338,366
Accounts receivable, net	366,286	345,875
Accounts receivable from consolidated subsidiaries	0	0
Inventories, net	427,778	395,744
Prepaid expenses and other current assets	72,481	47,882
Prepaid taxes	12,463	5,748
Total current assets	1,236,169	1,128,807
Property, plant and equipment, net	432,766	382,999	302,899
Goodwill	2,246,579	2,235,592	1,276,720
Intangibles assets, net	2,325,052	2,383,748
Investments in affiliates	0	0
Deferred tax assets	2,446	3,810
Notes receivable and other amounts due from consolidated subsidiaries	0	0
Other assets	34,979	46,536
Total assets	6,277,991	6,181,492
Current liabilities
Current borrowings	86,625	86,625
Accounts payable	106,709	92,027
Accounts payable to consolidated subsidiaries	0	0
Accrued expenses	97,551	96,853
Current portion of contingent consideration	136,877	74,224
Payroll and benefit-related liabilities	104,670	107,415
Accrued interest	6,031	6,165
Income taxes payable	5,943	11,514
Other current liabilities	38,050	9,053
Total current liabilities	582,456	483,876
Long-term borrowings	2,072,200	2,162,927
Deferred tax liabilities	608,221	603,676
Pension and postretirement benefit liabilities	92,914	121,410
Noncurrent liability for uncertain tax positions	10,718	12,296
Notes payable and other amounts due to consolidated subsidiaries	0	0
Noncurrent contingent consideration	167,370	197,912
Other liabilities	204,134	168,864
Total liabilities	3,738,013	3,750,961
Total shareholders' equity	2,539,978	2,430,531	2,137,517	2,011,093
Total liabilities and shareholders' equity	6,277,991	6,181,492
Eliminations
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	5,334	4,663
Accounts receivable from consolidated subsidiaries	(1,425,771)	(1,534,839)
Inventories, net	(30,954)	(26,279)
Prepaid expenses and other current assets	4,113	3,982
Prepaid taxes	0	0
Total current assets	(1,447,278)	(1,552,473)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangibles assets, net	0	0
Investments in affiliates	(7,677,731)	(7,499,941)
Deferred tax assets	(2,376)	(2,261)
Notes receivable and other amounts due from consolidated subsidiaries	(4,874,135)	(4,683,933)
Other assets	0	0
Total assets	(14,001,520)	(13,738,608)
Current liabilities
Current borrowings	0	0
Accounts payable	0	0
Accounts payable to consolidated subsidiaries	(1,425,771)	(1,534,839)
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	0	0
Other current liabilities	0	0
Total current liabilities	(1,425,771)	(1,534,839)
Long-term borrowings	0	0
Deferred tax liabilities	(2,376)	(2,261)
Pension and postretirement benefit liabilities	0	0
Noncurrent liability for uncertain tax positions	0	0
Notes payable and other amounts due to consolidated subsidiaries	(4,874,135)	(4,683,933)
Noncurrent contingent consideration	0	0
Other liabilities		0
Total liabilities	(6,302,282)	(6,221,033)
Total shareholders' equity	(7,699,238)	(7,517,575)
Total liabilities and shareholders' equity	(14,001,520)	(13,738,608)
Parent Company
Current assets
Cash and cash equivalents	49,523	37,803	14,571	21,612
Accounts receivable, net	5,885	2,414
Accounts receivable from consolidated subsidiaries	32,036	14,478
Inventories, net	0	0
Prepaid expenses and other current assets	30,458	14,874
Prepaid taxes	7,029	0
Total current assets	124,931	69,569
Property, plant and equipment, net	3,385	2,088
Goodwill	0	0
Intangibles assets, net	90	0
Investments in affiliates	5,984,566	5,806,244
Deferred tax assets	0	0
Notes receivable and other amounts due from consolidated subsidiaries	2,337,737	2,452,101
Other assets	17,180	31,173
Total assets	8,467,889	8,361,175
Current liabilities
Current borrowings	36,625	36,625
Accounts payable	3,448	4,269
Accounts payable to consolidated subsidiaries	1,058,008	1,211,568
Accrued expenses	5,659	17,957
Current portion of contingent consideration	0	0
Payroll and benefit-related liabilities	17,156	21,145
Accrued interest	5,995	6,133
Income taxes payable	0	4,352
Other current liabilities	843	1,461
Total current liabilities	1,127,734	1,303,510
Long-term borrowings	2,072,200	2,162,927
Deferred tax liabilities	87,671	88,512
Pension and postretirement benefit liabilities	49,290	70,860
Noncurrent liability for uncertain tax positions	801	1,117
Notes payable and other amounts due to consolidated subsidiaries	2,451,784	2,155,146
Noncurrent contingent consideration	0	0
Other liabilities	138,431	148,572
Total liabilities	5,927,911	5,930,644
Total shareholders' equity	2,539,978	2,430,531
Total liabilities and shareholders' equity	8,467,889	8,361,175
Guarantor Subsidiaries
Current assets
Cash and cash equivalents	1,757	8,933	1,031	0
Accounts receivable, net	54,013	57,818
Accounts receivable from consolidated subsidiaries	1,043,573	1,177,246
Inventories, net	266,073	245,533
Prepaid expenses and other current assets	9,673	9,236
Prepaid taxes	0	0
Total current assets	1,375,089	1,498,766
Property, plant and equipment, net	253,037	213,663
Goodwill	1,254,848	1,246,144
Intangibles assets, net	1,277,462	1,355,275
Investments in affiliates	1,672,908	1,674,077
Deferred tax assets	0	0
Notes receivable and other amounts due from consolidated subsidiaries	2,523,156	2,231,832
Other assets	5,776	6,397
Total assets	8,362,276	8,226,154
Current liabilities
Current borrowings	0	0
Accounts payable	62,764	46,992
Accounts payable to consolidated subsidiaries	278,715	261,121
Accrued expenses	41,883	31,827
Current portion of contingent consideration	106,514	74,224
Payroll and benefit-related liabilities	44,982	44,009
Accrued interest	0	0
Income taxes payable	0	0
Other current liabilities	34,916	3,775
Total current liabilities	569,774	461,948
Long-term borrowings	0	0
Deferred tax liabilities	257,522	265,426
Pension and postretirement benefit liabilities	27,454	32,750
Noncurrent liability for uncertain tax positions	7,212	8,196
Notes payable and other amounts due to consolidated subsidiaries	2,222,580	2,320,611
Noncurrent contingent consideration	131,563	186,923
Other liabilities	8,204	7,850
Total liabilities	3,224,309	3,283,704
Total shareholders' equity	5,137,967	4,942,450
Total liabilities and shareholders' equity	8,362,276	8,226,154
Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	305,881	286,822	$ 528,187	$ 316,754
Accounts receivable, net	301,054	280,980
Accounts receivable from consolidated subsidiaries	350,162	343,115
Inventories, net	192,659	176,490
Prepaid expenses and other current assets	28,237	19,790
Prepaid taxes	5,434	5,748
Total current assets	1,183,427	1,112,945
Property, plant and equipment, net	176,344	167,248
Goodwill	991,731	989,448
Intangibles assets, net	1,047,500	1,028,473
Investments in affiliates	20,257	19,620
Deferred tax assets	4,822	6,071
Notes receivable and other amounts due from consolidated subsidiaries	13,242	0
Other assets	12,023	8,966
Total assets	3,449,346	3,332,771
Current liabilities
Current borrowings	50,000	50,000
Accounts payable	40,497	40,766
Accounts payable to consolidated subsidiaries	89,048	62,150
Accrued expenses	50,009	47,069
Current portion of contingent consideration	30,363	0
Payroll and benefit-related liabilities	42,532	42,261
Accrued interest	36	32
Income taxes payable	5,943	7,162
Other current liabilities	2,291	3,817
Total current liabilities	310,719	253,257
Long-term borrowings	0	0
Deferred tax liabilities	265,404	251,999
Pension and postretirement benefit liabilities	16,170	17,800
Noncurrent liability for uncertain tax positions	2,705	2,983
Notes payable and other amounts due to consolidated subsidiaries	199,771	208,176
Noncurrent contingent consideration	35,807	10,989
Other liabilities	57,499	12,442
Total liabilities	888,075	757,646
Total shareholders' equity	2,561,271	2,575,125
Total liabilities and shareholders' equity	$ 3,449,346	$ 3,332,771