Business Segment Information - Segment Operating Performance (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Net sales	$ 502.2	$ 398.6	$ 929.1	$ 752.1
Cost of sales	358.4	336.4	666.4	647.9
Gross margin	143.8	62.2	262.7	104.2
Operating income (loss)	(92.8)	9.8	(32.1)	(0.5)
Securities earnings	7.2	6.9	14.2	13.7
Insurance recoveries		0.2	0.1	0.3
Termination fee	4.0		4.0
General expenses, net	(14.7)	(8.6)	(27.1)	(20.1)
Interest expense	(16.0)	(15.8)	(31.6)	(31.5)
Loss before income taxes	(112.3)	(7.5)	(72.5)	(38.1)
Chemicals
Segment Reporting Information [Line Items]
Net sales	441.4	356.0	811.2	674.5
Cost of sales	312.1	301.0	578.9	579.5
Gross margin	129.3	55.0	232.3	95.0
Operating income (loss)	73.0	12.7	128.0	15.7
Component Products
Segment Reporting Information [Line Items]
Net sales	30.1	27.1	60.0	54.2
Cost of sales	20.5	18.6	40.8	37.5
Gross margin	9.6	8.5	19.2	16.7
Operating income (loss)	4.6	3.7	9.1	7.1
Waste Management
Segment Reporting Information [Line Items]
Net sales	20.5	11.1	42.0	16.3
Cost of sales	17.9	13.6	34.6	25.3
Gross margin	2.6	(2.5)	7.4	(9.0)
Operating income (loss)	(171.6)	(7.1)	(171.0)	(17.9)
Real Estate Management And Development
Segment Reporting Information [Line Items]
Net sales	10.2	4.4	15.9	7.1
Cost of sales	7.9	3.2	12.1	5.6
Gross margin	2.3	1.2	3.8	1.5
Operating income (loss)	$ 1.2	$ 0.5	$ 1.8	$ (5.4)