Stockholders' Equity	12 Months Ended
Dec. 31, 2017
Equity [Abstract]
STOCKHOLDERS’ EQUITY	STOCKHOLDERS’ EQUITY Registered Underwritten Public Offerings On September 21, 2016, the Company completed the September 2016 Equity Offering of 48,787,878 shares of its common stock at a public offering price of $8.25 per share. This offering resulted in gross proceeds to Platform of approximately $402.5 million, before underwriting discounts and commissions and offering expenses of $11.9 million. On June 29, 2015, the Company completed the June 2015 Equity Offering of 18,226,414 shares of its common stock at a public offering price of $26.50 per share. The offering resulted in gross proceeds to Platform of approximately $483 million, before underwriting discounts, commissions and offering expenses of $15.0 million. Preferred Stock The Company is authorized to issue 5,000,000 shares of preferred stock. The Board had designated 2,000,000 of those shares as "Series A Preferred Stock." At December 31, 2017 and 2016, a total of 2,000,000 shares of Series A Preferred Stock were issued and outstanding. The Board had also designated 600,000 of those shares as "Series B Convertible Preferred Stock." At December 31, 2017 and 2016, all shares of Series B Convertible Preferred Stock were either converted or subsequently canceled and retired as noted below. Shares of preferred stock have no voting rights, except in respect of any amendment to the Company's Certificate of Incorporation, as amended, that would alter or change their rights or privileges. Series A Preferred Stock The Founder Entities are current holders of Platform's outstanding 2,000,000 shares of Series A Preferred Stock and are entitled to receive an annual dividend on such Series A Preferred Stock in the form of shares of the Company's common stock. On December 31, 2014, the Board approved a stock dividend of 10,050,290 shares of Platform's common stock with respect to its outstanding Series A Preferred Stock, which represented 20% of the appreciation of the market price of the Company's common stock over the May 22, 2013 initial public offering price of Platform's stock on the London Stock Exchange of $10.00 multiplied by the total of shares offered in this initial public offering. The dividend price was $22.85 and the shares were issued on January 2, 2015 based on the volume weighted average price of $23.16 on December 31, 2014. Starting with fiscal year 2015, the dividend amount is calculated based on the appreciated stock price compared to the highest dividend price previously used in calculating the Series A Preferred Stock dividends. Based on the dividend price of $22.85 used in 2014, no stock dividends were declared in 2017, 2016 and 2015 with respect to the Series A Preferred Stock. Each share of Series A Preferred Stock is convertible into one share of common stock of Platform at the option of the holder until December 31, 2020. All outstanding shares of Series A Preferred Stock will be automatically converted into shares of common stock on a one-for-one basis (i) in the event of a change of control of the Company following an acquisition, or (ii) on December 31, 2020 (which may be extended by the Board for three additional years). Series B Convertible Preferred Stock On December 13, 2016, in accordance with a settlement agreement dated September 9, 2016, as amended, the Company settled all of its obligations with respect to its then outstanding 600,000 shares of Series B Convertible Preferred Stock, issued to the Arysta Seller in connection with the Arysta Acquisition, and the related make whole payment obligation, as described in the settlement agreement, in exchange for a cash payment of $460 million and the issuance of 5,500,000 shares of its common stock upon conversion of the corresponding shares of Series B Convertible Preferred Stock. The remaining shares of Series B Convertible Preferred Stock were subsequently canceled and retired. As a result of the settlement agreement, for accounting purposes, the Series B Convertible Preferred Stock had been deemed an extinguishment in exchange for the issuance of another financial instrument. During 2016, the Company recognized a gain of $103 million in "Other (expense) income, net" in the Consolidated Statement of Operations and a gain of $32.9 million in "Net loss attributable to common stockholders." The Company elected the fair value option to measure the preferred stock redemption liability subsequent to the date of the settlement agreement as it most accurately reflected the economics of the transaction and the value of the preferred stock redemption liability. During 2016, the Company recorded a $5.0 million loss associated with the remeasurement of the preferred stock redemption liability, which was recorded to "Other (expense) income, net" in the Consolidated Statement of Operations. Issuance of Common Stock in Connection with Acquisitions In connection with the Alent Acquisition, on December 2, 2015, the Company issued 18,419,738 shares of its common stock to Alent shareholders. The shares were issued in reliance upon an exemption from the registration requirements of the Securities Act set forth in Section 3(a)(10) thereof and began trading on the NYSE upon their issuance. Non-Controlling Interest In connection with the MacDermid Acquisition, approximately $97.5 million was raised in new equity consisting of 8,774,527 shares of PDH Common Stock. The PDH Common Stock is classified in the Consolidated Balance Sheets as "Non-controlling interests"at December 31, 2017 and 2016 and will continue to be classified as such until it is fully converted into shares of the Company's common stock. Of the shares initially issued, 3,961,785 have been converted and a like number of shares of the Company's common stock have been issued through December 31, 2017. Non-controlling interest at December 31, 2017, 2016 and 2015, totaled 3.83%, 6.01% and 6.25%, respectively. During 2017, 2016 and 2015, approximately $2.1 million, $(5.9) million and $(1.4) million, respectively, of net income (loss) has been allocated to the Retaining Holders, as included in the Consolidated Statements of Operations.

STOCKHOLDERS’ EQUITY

Registered Underwritten Public Offerings

On September 21, 2016, the Company completed the September 2016 Equity Offering of 48,787,878 shares of its common stock at a public offering price of $8.25 per share. This offering resulted in gross proceeds to Platform of approximately $402.5 million, before underwriting discounts and commissions and offering expenses of $11.9 million.

On June 29, 2015, the Company completed the June 2015 Equity Offering of 18,226,414 shares of its common stock at a public offering price of $26.50 per share. The offering resulted in gross proceeds to Platform of approximately $483 million, before underwriting discounts, commissions and offering expenses of $15.0 million.

Preferred Stock

The Company is authorized to issue 5,000,000 shares of preferred stock. The Board had designated 2,000,000 of those shares as "Series A Preferred Stock." At December 31, 2017 and 2016, a total of 2,000,000 shares of Series A Preferred Stock were issued and outstanding. The Board had also designated 600,000 of those shares as "Series B Convertible Preferred Stock." At December 31, 2017 and 2016, all shares of Series B Convertible Preferred Stock were either converted or subsequently canceled and retired as noted below. Shares of preferred stock have no voting rights, except in respect of any amendment to the Company's Certificate of Incorporation, as amended, that would alter or change their rights or privileges.

Series A Preferred Stock

The Founder Entities are current holders of Platform's outstanding 2,000,000 shares of Series A Preferred Stock and are entitled to receive an annual dividend on such Series A Preferred Stock in the form of shares of the Company's common stock. On December 31, 2014, the Board approved a stock dividend of 10,050,290 shares of Platform's common stock with respect to its outstanding Series A Preferred Stock, which represented 20% of the appreciation of the market price of the Company's common stock over the May 22, 2013 initial public offering price of Platform's stock on the London Stock Exchange of $10.00 multiplied by the total of shares offered in this initial public offering. The dividend price was $22.85 and the shares were issued on January 2, 2015 based on the volume weighted average price of $23.16 on December 31, 2014. Starting with fiscal year 2015, the dividend amount is calculated based on the appreciated stock price compared to the highest dividend price previously used in calculating the Series A Preferred Stock dividends. Based on the dividend price of $22.85 used in 2014, no stock dividends were declared in 2017, 2016 and 2015 with respect to the Series A Preferred Stock.

Each share of Series A Preferred Stock is convertible into one share of common stock of Platform at the option of the holder until December 31, 2020. All outstanding shares of Series A Preferred Stock will be automatically converted into shares of common stock on a one-for-one basis (i) in the event of a change of control of the Company following an acquisition, or (ii) on December 31, 2020 (which may be extended by the Board for three additional years).

Series B Convertible Preferred Stock

On December 13, 2016, in accordance with a settlement agreement dated September 9, 2016, as amended, the Company settled all of its obligations with respect to its then outstanding 600,000 shares of Series B Convertible Preferred Stock, issued to the Arysta Seller in connection with the Arysta Acquisition, and the related make whole payment obligation, as described in the settlement agreement, in exchange for a cash payment of $460 million and the issuance of 5,500,000 shares of its common stock upon conversion of the corresponding shares of Series B Convertible Preferred Stock. The remaining shares of Series B Convertible Preferred Stock were subsequently canceled and retired.

As a result of the settlement agreement, for accounting purposes, the Series B Convertible Preferred Stock had been deemed an extinguishment in exchange for the issuance of another financial instrument. During 2016, the Company recognized a gain of $103 million in "Other (expense) income, net" in the Consolidated Statement of Operations and a gain of $32.9 million in "Net loss attributable to common stockholders." The Company elected the fair value option to measure the preferred stock redemption liability subsequent to the date of the settlement agreement as it most accurately reflected the economics of the transaction and the value of the preferred stock redemption liability. During 2016, the Company recorded a $5.0 million loss associated with the remeasurement of the preferred stock redemption liability, which was recorded to "Other (expense) income, net" in the Consolidated Statement of Operations.

Issuance of Common Stock in Connection with Acquisitions

In connection with the Alent Acquisition, on December 2, 2015, the Company issued 18,419,738 shares of its common stock to Alent shareholders. The shares were issued in reliance upon an exemption from the registration requirements of the Securities Act set forth in Section 3(a)(10) thereof and began trading on the NYSE upon their issuance.

Non-Controlling Interest

In connection with the MacDermid Acquisition, approximately $97.5 million was raised in new equity consisting of 8,774,527 shares of PDH Common Stock. The PDH Common Stock is classified in the Consolidated Balance Sheets as "Non-controlling interests"at December 31, 2017 and 2016 and will continue to be classified as such until it is fully converted into shares of the Company's common stock. Of the shares initially issued, 3,961,785 have been converted and a like number of shares of the Company's common stock have been issued through December 31, 2017. Non-controlling interest at December 31, 2017, 2016 and 2015, totaled 3.83%, 6.01% and 6.25%, respectively.

During 2017, 2016 and 2015, approximately $2.1 million, $(5.9) million and $(1.4) million, respectively, of net income (loss) has been allocated to the Retaining Holders, as included in the Consolidated Statements of Operations.