Summary of significant accounting policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2015 tradename unit	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reporting units | unit	6
Number of reporting units, two-step quantitative impairment test | unit	3
Number of trade names | tradename	2
Impairment charges		$ 0	$ 0	$ 10,841,000
Weighted average amortization period of intangible assets, in years		15 years
Reserve for returns and allowances		$ 4,900,000	4,100,000
Reserve for estimated rebates		$ 11,100,000	$ 10,400,000
Minimum | Intellectual property
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		3 years
Minimum | Customer Lists
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		5 years
Minimum | Distribution rights
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		3 years
Minimum | Trade names
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		1 year
Maximum | Intellectual property
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		20 years
Maximum | Customer Lists
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		30 years
Maximum | Distribution rights
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		22 years
Maximum | Trade names
Summary Of Significant Accounting Policies [Line Items]
Useful life of Intangible assets, in years		30 years
Land Improvements
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		5 years
Building
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		30 years
Machinery and Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		3 years
Machinery and Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		10 years
Computer Equipment and Software | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		3 years
Computer Equipment and Software | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life of plant and equipment, in years		10 years