Investments (Tables)

12 Months Ended

Dec. 31, 2018

Investments [Abstract]

Investment Balances

The following table details our investment balances at December 31, 2018 and 2017 (in thousands):

	December 31,
	2018		2017
Joint ventures	$	486,032	$	499,756
Nonmarketable securities	9,177		3,655
Marketable equity securities	33,513		30,653
Total	$	528,722	$	534,064

Ownership Positions in Significant Unconsolidated Investments

Our ownership positions in significant unconsolidated investments are shown below:

		December 31,
		2018		2017		2016
*	Windfield Holdings Pty. Ltd. - a joint venture with Sichuan Tianqi Lithium Industries, Inc., that mines lithium ore and produces lithium concentrate	49	%	49	%	49	%
*	Nippon Aluminum Alkyls - a joint venture with Mitsui Chemicals, Inc. that produces aluminum alkyls	50	%	50	%	50	%
*	Nippon Ketjen Company Limited - a joint venture with Sumitomo Metal Mining Company Limited that produces refinery catalysts	50	%	50	%	50	%
*	Eurecat S.A. - a joint venture with Axens Group for refinery catalysts regeneration services	50	%	50	%	50	%
*	Fábrica Carioca de Catalisadores S.A. - a joint venture with Petrobras Quimica S.A. - PETROQUISA that produces catalysts and includes catalysts research and product development activities	50	%	50	%	50	%

Summary of Assets, Liabilities and Results of Operations for Significant Unconsolidated Joint Ventures

The following summary lists the assets, liabilities and results of operations for our significant unconsolidated joint ventures presented herein (in thousands):

	December 31,
	2018		2017
Summary of Balance Sheet Information:
Current assets	$	476,460	$	503,043
Noncurrent assets	1,159,866		1,041,519
Total assets	$	1,636,326	$	1,544,562
Current liabilities	$	191,971	$	133,670
Noncurrent liabilities	422,769		405,662
Total liabilities	$	614,740	$	539,332

	Year Ended December 31,
	2018		2017		2016
Summary of Statements of Income Information:
Net sales	$	829,590	$	687,561	$	590,980
Gross profit	$	456,518	$	353,577	$	267,241
Income before income taxes	$	332,632	$	267,805	$	189,016
Net income	$	225,791	$	184,777	$	126,872