Business Segment Information - Segment Operating Performance (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 353.5	$ 416.1
Cost of sales	311.5	326.8
Gross margin	42.0	89.3
Operating income (loss)	(10.3)	34.6
Securities earnings	6.8	6.7
Insurance recoveries	0.1	3.1
General expenses, net	(11.5)	(8.2)
Interest expense	(15.7)	(14.6)
Income (loss) before income taxes	(30.6)	21.6
Chemicals
Segment Reporting Information [Line Items]
Net sales	318.5	365.1
Cost of sales	278.5	288.2
Gross margin	40.0	76.9
Operating income (loss)	3.0	34.0
Component Products
Segment Reporting Information [Line Items]
Net sales	27.1	27.9
Cost of sales	18.9	19.3
Gross margin	8.2	8.6
Operating income (loss)	3.4	3.7
Waste Management
Segment Reporting Information [Line Items]
Net sales	5.2	15.0
Cost of sales	11.7	12.1
Gross margin	(6.5)	2.9
Operating income (loss)	(10.8)	(2.9)
Real Estate Management And Development
Segment Reporting Information [Line Items]
Net sales	2.7	8.1
Cost of sales	2.4	7.2
Gross margin	0.3	0.9
Operating income (loss)	$ (5.9)	$ (0.2)