Business Segment Information - Segment Operating Performance (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Net sales	$ 398.6	$ 408.8	$ 752.1	$ 824.9
Cost of sales	336.4	352.5	647.9	679.3
Gross margin	62.2	56.3	104.2	145.6
Operating income (loss)	9.8	(10.1)	(0.5)	24.5
Securities earnings	6.9	6.7	13.7	13.4
Insurance recoveries	0.2	0.3	0.3	3.4
General expenses, net	(8.6)	(11.2)	(20.1)	(19.4)
Interest expense	(15.8)	(14.5)	(31.5)	(29.1)
Loss before income taxes	(7.5)	(28.8)	(38.1)	(7.2)
Chemicals
Segment Reporting Information [Line Items]
Net sales	356.0	360.2	674.5	725.3
Cost of sales	301.0	314.2	579.5	602.4
Gross margin	55.0	46.0	95.0	122.9
Operating income (loss)	12.7	(7.9)	15.7	26.1
Component Products
Segment Reporting Information [Line Items]
Net sales	27.1	28.9	54.2	56.8
Cost of sales	18.6	19.8	37.5	39.1
Gross margin	8.5	9.1	16.7	17.7
Operating income (loss)	3.7	4.3	7.1	8.0
Waste Management
Segment Reporting Information [Line Items]
Net sales	11.1	10.0	16.3	25.0
Cost of sales	13.6	12.4	25.3	24.5
Gross margin	(2.5)	(2.4)	(9.0)	0.5
Operating income (loss)	(7.1)	(8.1)	(17.9)	(11.0)
Real Estate Management And Development
Segment Reporting Information [Line Items]
Net sales	4.4	9.7	7.1	17.8
Cost of sales	3.2	6.1	5.6	13.3
Gross margin	1.2	3.6	1.5	4.5
Operating income (loss)	$ 0.5	$ 1.6	$ (5.4)	$ 1.4