Acquisitions of Businesses (Details) £ / shares in Units, £ in Millions, $ in Millions						3 Months Ended				9 Months Ended		12 Months Ended
	Jul. 13, 2015 GBP (£) £ / shares £ / $ shares	Feb. 13, 2015 USD ($)	Nov. 03, 2014 USD ($) agreement shares	Oct. 01, 2014 USD ($)	Oct. 01, 2014 EUR (€)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) product_line	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2015 MXN / $	Sep. 30, 2015 BRL / $	Jul. 31, 2015 GBP (£)	Jul. 31, 2015 USD ($)	Jul. 13, 2015 USD ($) £ / $	Jul. 10, 2015	Jun. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Number of pence per ordinary share of acquiree | £ / shares	£ 0.503
Transaction related costs						$ 15.0			$ 7.7	$ 70.4	$ 18.4
Capital lease obligations						4.3				4.3		$ 2.0
Asset retirement obligations						17.8	$ 17.7		5.5	17.8	5.5	18.5							$ 5.4	$ 4.8
Option reversal value						(1.4)			$ 0.0	(19.8)	$ 0.0
Foreign currency exchange rate													0.0591	0.2527
Arysta [Member]
Business Acquisition [Line Items]
Total Consideration		$ 3,502.1
Cash, net		2,856.2
Common stock restricted shares (in shares)		600.0
Equity Instruments		645.9
Transaction related costs		$ 38.6				4.4				32.2
CAS [Member]
Business Acquisition [Line Items]
Total Consideration			$ 1,035.1
Cash, net			983.1
Equity Instruments			52.0
Transaction related costs			$ 45.4
Business acquisition, shares of common stock issued (in shares) | shares			2,000,000
Number of supply agreements | agreement			6
Capital lease obligations							13.2
Depreciation							$ 2.2
Asset retirement obligations						13.2				$ 13.2
Minimum supply agreement term			4 years
Major product lines | product_line										7
Preliminary estimate of its equity interest						10.1
Preliminary estimate of its equity interest after reduction						5.0
Purchase accounting adjustments						10.1
Goodwill, expected to be tax deductible						185.0				$ 185.0
Arysta, CAS, Agriphar [Member]
Business Acquisition [Line Items]
Goodwill acquired										$ 2,220.0
Agriphar [Member]
Business Acquisition [Line Items]
Total Consideration				$ 370.3	€ 300,000,000
Cash, net				350.2
Common stock restricted shares (in shares) | €					€ 711,551
Equity Instruments				16.6
Transaction related costs				$ 5.1
Option reversal value								$ (3.0)
Agriphar Acquisition [Member]
Business Acquisition [Line Items]
First portion of restricted stock transfer										33.33%
Second portion of restricted stock transfer										33.33%
Third portion of restricted stock transfer										33.33%
Certis Europe BV [Member] | CAS [Member]
Business Acquisition [Line Items]
Percentage equity in acquisition			15.00%
Selling, General and Administrative Expenses [Member] | Arysta [Member]
Business Acquisition [Line Items]
Transaction related costs						4.4				$ 32.2		6.4
Selling, General and Administrative Expenses [Member] | CAS [Member]
Business Acquisition [Line Items]
Transaction related costs						1.7				11.5		33.9
Selling, General and Administrative Expenses [Member] | Agriphar Acquisition [Member]
Business Acquisition [Line Items]
Transaction related costs						$ 0.1				$ 0.9		$ 4.2
Customer Lists [Member] | Arysta [Member]
Business Acquisition [Line Items]
Intangible asset useful life		20 years
Developed Technology Rights [Member] | Arysta [Member]
Business Acquisition [Line Items]
Intangible asset useful life		12 years
Cash [Member] | CAS [Member]
Business Acquisition [Line Items]
Total Consideration			$ 983.0
Mac Dermid [Member] | Alent [Member]
Business Acquisition [Line Items]
Acquiree shareholders number of acquiring company shares exchanged in lieu of cash	0.31523
New share issuance limited to acquiree share capital	21.90%
Acquiree share capital	£ 1,350																$ 2,100.0
Foreign currency exchange rate																		1.5517
Irrevocable undertaking ownership (in shares) | shares	58,432,694
Unsecured Debt [Member] | Letter of Credit [Member] | Alent [Member]
Business Acquisition [Line Items]
Revolving credit facility																	$ 1,880.0
Break-Up Fee [Member] | Alent [Member]
Business Acquisition [Line Items]
Break-up fee | £	£ 27
Foreign Exchange Forward [Member]
Business Acquisition [Line Items]
Foreign currency exchange rate | £ / $	1.5487																1.5487
Debt amount affected by interest rate swap															£ 1,060	$ 1,640.0
Percentage of forward at fixed exchange rate															50.00%	50.00%
Maximum [Member] | Developed Technology Rights [Member]
Business Acquisition [Line Items]
Intangible asset useful life										14 years
Maximum [Member] | Foreign Exchange Forward [Member]
Business Acquisition [Line Items]
Exchange rate on 50% of forward contract | £ / $	1.6244																1.6244