Commitments, Contingencies and Guarantees - Additional Information (Details)				6 Months Ended	9 Months Ended	12 Months Ended
	May 01, 2019 USD ($)	Mar. 08, 2018 USD ($)	Jan. 17, 2017 USD ($)	Jun. 30, 2019 USD ($) $ / shares	Sep. 30, 2019 USD ($) T	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Annual purchase commitment, in tons | T					240,000
Commitments					$ 227,300,000
Outstanding guarantees and letters of credit					4,900,000
Estimated minimum compensatory punitive damages					20,000,000.0
Agro Bio Sciences Inc
Commitments And Contingencies Disclosure [Line Items]
Payment year of achieving certain operating performance			2019
Payment to be made if certain operating performance is achieved							$ 17,800,000
Passport Food Safety Solutions, Inc.
Commitments And Contingencies Disclosure [Line Items]
Payment year of achieving certain operating performance				2020
Payment to be made if certain operating performance is achieved		$ 7,300,000		$ 7,300,000
Flawless Acquisition
Commitments And Contingencies Disclosure [Line Items]
Payment year of achieving certain operating performance				2021
Payment to be made if certain operating performance is achieved	$ 182,000,000.0			$ 182,000,000.0
Maximum | Agro Bio Sciences Inc
Commitments And Contingencies Disclosure [Line Items]
Additional earn-out payment			$ 25,000,000.0
Maximum | Passport Food Safety Solutions, Inc.
Commitments And Contingencies Disclosure [Line Items]
Additional earn-out payment		$ 25,000,000.0		25,000,000.0
Maximum | Flawless Acquisition
Commitments And Contingencies Disclosure [Line Items]
Additional earn-out payment	$ 425,000,000.0			425,000,000.0
Updated Sales Forecasts | Agro Bio Sciences Inc
Commitments And Contingencies Disclosure [Line Items]
Payment to be made if certain operating performance is achieved						$ 15,700,000
Updated Sales Forecasts | Passport Food Safety Solutions, Inc.
Commitments And Contingencies Disclosure [Line Items]
Reversed contingent liability				7,300,000
Reversed contingent liability after tax				$ 5,500,000
Reversed contingent liability diluted per share | $ / shares				$ 0.02
Updated Sales Forecasts | Flawless Acquisition
Commitments And Contingencies Disclosure [Line Items]
Increase (decrease) in estimate of contingent consideration liability				$ 17,000,000.0
Payment to be made if certain operating performance is achieved				199,000,000.0	$ 199,000,000.0
Increase (decrease) in estimate of contingent consideration liability after tax				$ 12,700,000
Increase (decrease) in estimate of contingent consideration liability diluted per share | $ / shares				$ 0.05
Updated Sales Forecasts | Selling, General and Administrative Expenses | Specialty Products | Agro Bio Sciences Inc
Commitments And Contingencies Disclosure [Line Items]
Increase (decrease) in estimate of contingent consideration liability						$ (2,100,000)