Acquisition (Purchase Price Allocation) (Details) - USD ($) $ in Thousands	Aug. 31, 2016	Mar. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 950,681	$ 946,553
Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted average useful life	10 years 8 months 12 days
Trade Name [Member]
Business Acquisition [Line Items]
Weighted average useful life	6 years 9 months 18 days
Technology [Member]
Business Acquisition [Line Items]
Weighted average useful life	5 years 4 months 24 days
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]
Business Combination, Acquired Receivables, Fair Value	$ 422,459
Cash	88,251
Accounts receivable (1)	422,459
Income tax receivable	55,193
Inventories	306,158
Prepaid expenses and other current assets	55,462
Property, plant and equipment	3,134,741
Other assets	98,708
Total assets acquired	4,869,760
Accounts and notes payable	255,232
Interest payable	8,154
Income tax payable	967
Accrued compensation	44,186
Accrued liabilities	152,550
Deferred income taxes	985,128
Tax reserve non-current	3,130
Pension and other post-retirement obligations	311,106
Other liabilities	99,848
Long-term debt	1,187,290
Total liabilities assumed	3,047,591
Total identifiable net assets acquired	1,822,169
Noncontrolling interest	(68,000)
Goodwill	887,491
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	12,375
Axiall Corporation [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	590,000
Axiall Corporation [Member] | Trade Name [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	50,000
Axiall Corporation [Member] | Technology [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	41,500
Axiall Corporation [Member] | Supply Contracts and Leases [Member]
Business Acquisition [Line Items]
Finite-lived intangibles	$ 27,288