Acquisition (Purchase Price Allocation) (Details) - USD ($) $ in Thousands		9 Months Ended
	Aug. 31, 2016	Sep. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 1,011,342	$ 946,553
Goodwill, Purchase Accounting Adjustments		$ 54,605
Axiall Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted average useful life	9 years 9 months 18 days
Axiall Trade Name [Member]
Business Acquisition [Line Items]
Weighted average useful life	6 years 9 months 18 days
Axiall Technology [Member]
Business Acquisition [Line Items]
Weighted average useful life	5 years 4 months 24 days
Axiall Supply Contracts and Leases [Member]
Business Acquisition [Line Items]
Weighted average useful life	6 years 3 months 18 days
Axiall Corporation [Member]
Business Acquisition [Line Items]
Cash	$ 88,251
Accounts Receivable (1)	422,274
Income tax receivable	50,980
Inventories (2)	349,205
Prepaid expenses and other current assets	55,462
Property, plant and equipment (2)	2,942,162
Other assets	93,875
Total assets acquired	4,790,997
Accounts and notes payable	254,041
Interest payable	8,154
Income tax payable	1,607
Accrued compensation	44,186
Accrued liabilities	154,290
Deferred income taxes (4)	958,304
Tax reserve non-current	3,130
Pension and other post-retirement obligations	311,106
Other liabilities	101,325
Long-term debt	1,187,290
Total liabilities assumed	3,023,433
Total identifiable net assets acquired	1,767,564
Noncontrolling interest	(68,000)
Goodwill	942,096
Total fair value allocated to net assets acquired	2,641,660
Business Combination, Acquired Receivables, Gross Contractual Amount	434,834
Business Combination, Acquired Receivables, Estimated Uncollectible	12,560
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory	43,047
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment	(192,579)
Goodwill, Purchase Accounting Adjustments	149,532
Axiall Corporation [Member] | Axiall Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	670,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles	80,000
Axiall Corporation [Member] | Axiall Trade Name [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	50,000
Axiall Corporation [Member] | Axiall Technology [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	41,500
Axiall Corporation [Member] | Axiall Supply Contracts and Leases [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	27,288
Deferred Income Tax Change [Member]
Business Acquisition [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments Related to Previous Period	$ (26,824)