Supplemental Information (Other Income, Net) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest income	$ 644	$ 537	$ 1,578	$ 6,900
Dividend income	127	574	250	1,499
Acquisition-related financing costs	0	11,420	0	12,220
Foreign exchange currency loss, net	(3,197)	(1,281)	(9,483)	(2,435)
Gain realized on previously held shares of Axiall common stock	0	49,080	0	49,080
Gains from sales of securities, net	0	3,321	0	4,640
Income from non-consolidated subsidiaries	3,855	1,475	11,066	7,213
Other	629	(1,021)	3,180	(2,586)
Other income, net	$ 2,058	$ 41,265	$ 6,591	$ 52,091