LONG-TERM DEBT AND LEASE FINANCING OBLIGATION (Details)		9 Months Ended
	Feb. 27, 2015 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Feb. 01, 2013 USD ($)
Debt Instrument
Total debt		$ 1,383,500,000	$ 1,330,600,000
Less: current portion of long-term debt		(2,500,000)	(2,800,000)
Long-term debt, net		1,381,000,000	1,327,800,000
Lease financing obligation		$ 82,200,000	94,200,000
Lease financing obligation term		10 years
Future minimum lease payments
2015		$ 1,200,000
2016		4,800,000
2017		$ 1,200,000
Letter of Credit
Debt Instrument
Collateralized letter of credit expiration date		Feb. 02, 2015
4.625 Notes
Debt Instrument
Total debt		$ 688,000,000	$ 688,000,000
Debt maturity date		Feb. 15, 2021
Principal amount		$ 688,000,000
Stated Interest Rate (as a percent)		4.625%	4.625%
Debt instrument, interest payment description		Interest is payable semi-annually in arrears on February 15 and August 15 of each year.
4.875 Notes
Debt Instrument
Total debt		$ 450,000,000	$ 450,000,000
Debt maturity date		May 15, 2023
Principal amount				$ 450,000,000
Stated Interest Rate (as a percent)		4.875%
Debt instrument, interest payment description		Interest is payable semi-annually in arrears on May 15 and November 15 of each year.
Term Loan | Due 2017
Debt Instrument
Total debt			192,600,000
Debt maturity date		Jan. 28, 2017
Term Loan | Due 2022
Debt Instrument
Total debt		$ 245,500,000
Debt maturity date		Feb. 27, 2022
Stated Interest Rate (as a percent)		4.00%
Term Loan | Due 2022 | Axiall Holdco
Debt Instrument
Principal amount	$ 250,000,000
Additional amount of term loans permitted under term loan facility subject to certain conditions	$ 250,000,000
Maximum consolidated secured debt ratio related to additional amount of term loans permitted under term loan facility	2.50
Term Loan | Due 2022 | Axiall Holdco | Base Rate
Debt Instrument
Variable interest rate margin (as a percent)	1.50%
Variable interest rate basis floor (as a percent)	2.00%
Term Loan | Due 2022 | Axiall Holdco | LIBOR
Debt Instrument
Variable interest rate margin (as a percent)	3.25%
Variable interest rate basis floor (as a percent)	0.75%
ABL Revolver
Debt Instrument
Total debt		$ 0	$ 0
Debt maturity date		Dec. 17, 2019
Maximum borrowing capacity		$ 600,000,000
Maximum cash dividends if conditions are met		150,000,000
Availability under the credit facility that, if exceeded, limits the cash dividend payments the entity is allowed to make		$ 75,000,000
Consecutive period of borrowing availability under the credit facility used to determine cash dividend payments allowed		30 days
Fixed charge coverage ratio that, if exceeded, limits the cash dividend payments the entity is allowed to make		100.00%
Availability under the credit facility that, if exceeded, allows the entity to make additional cash dividend payments		$ 100,000,000
Fixed charge coverage ratio, if exceeded, allows the entity to make additional cash dividend payments		110.00%
Availability under the credit facility		$ 438,800,000
Outstanding letters of credit		$ 81,900,000
Debt instrument, covenant compliance		As of September 30, 2015, we were in compliance with the covenants under our ABL Credit Agreement, the Term Loan Agreement and the indentures governing the 4.625 Notes and the 4.875 Notes.
ABL Revolver | LIBOR or Certain United States Index Rates | Minimum
Debt Instrument
Variable interest rate margin (as a percent)		3.20%
ABL Revolver | LIBOR or Certain United States Index Rates | Maximum
Debt Instrument
Variable interest rate margin (as a percent)		3.75%