Investments Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Investments [Line Items]
Equity in net income of unconsolidated investments (net of tax)		$ 30,999	$ 35,742	$ 31,729
Dividends received from unconsolidated investments		59,912	40,688	21,632
Investments in unconsolidated joint ventures exceeded the amount of underlying equity in net assets		11,500	7,000
Excess amount paid for joint ventures remaining to be amortized		800	1,000
Return of capital from unconsolidated investment		98,000	0	0
Marketable equity securities		24,257	23,974
Long-term advances to joint ventures	[1]	31,780	34,084
Significant Unconsolidated Joint Venture
Schedule of Investments [Line Items]
Investment in significant unconsolidated joint ventures		402,600	148,300
Equity in net income of unconsolidated investments (net of tax)		25,400	34,700	32,200
Undistributed earnings from equity method investees		105,900	107,800
Dividends received from unconsolidated investments		$ 58,100	$ 39,600	$ 20,100
Windfield Holdings
Schedule of Investments [Line Items]
Ownership percentage		49.00%	0.00%	0.00%
Return of capital from unconsolidated investment		$ 98,000
Saudi Organometallic Chemicals Company
Schedule of Investments [Line Items]
Ownership percentage		50.00%
Interest rate margin over LIBOR		1.275%
Benefit Protection Trust
Schedule of Investments [Line Items]
Marketable equity securities		$ 21,600	$ 22,200
Other Assets | Saudi Organometallic Chemicals Company
Schedule of Investments [Line Items]
Long-term advances to joint ventures		$ 30,000	30,000
Windfield Holdings
Schedule of Investments [Line Items]
Ownership percentage		49.00%
Carrying value of unconsolidated investment		$ 280,200
Other Variable Interest Entities Excluding Windfield Holdings
Schedule of Investments [Line Items]
Carrying value of unconsolidated investment		27,600	$ 6,200
Rockwood Holdings, Inc.
Schedule of Investments [Line Items]
Utilization of inventory markup		103,000
Equity in Net Income of Unconsolidated Investments | Rockwood Holdings, Inc.
Schedule of Investments [Line Items]
Utilization of inventory markup		$ 27,100

[1] See Note 10, “Investments.”