Business Segment Information - Segment Operating Performance (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Net sales	$ 406.8	$ 383.2	$ 1,158.9	$ 1,208.1
Cost of sales	321.5	333.4	969.4	1,012.7
Gross margin	85.3	49.8	189.5	195.4
Operating income (loss)	29.7	(5.0)	29.2	19.5
Securities earnings	6.8	6.5	20.5	19.9
Insurance recoveries	0.1	0.1	0.4	3.5
General expenses, net	(9.1)	(10.0)	(29.2)	(29.4)
Interest expense	(15.9)	(14.4)	(47.4)	(43.5)
Income (loss) before income taxes	11.6	(22.8)	(26.5)	(30.0)
Chemicals
Segment Reporting Information [Line Items]
Net sales	356.1	336.5	1,030.6	1,061.8
Cost of sales	281.1	293.7	860.6	896.1
Gross margin	75.0	42.8	170.0	165.7
Operating income (loss)	30.1	(1.3)	45.8	24.8
Component Products
Segment Reporting Information [Line Items]
Net sales	28.4	26.5	82.6	83.3
Cost of sales	19.0	18.4	56.5	57.5
Gross margin	9.4	8.1	26.1	25.8
Operating income (loss)	4.4	3.4	11.5	11.4
Waste Management
Segment Reporting Information [Line Items]
Net sales	13.6	9.9	29.9	34.9
Cost of sales	14.1	13.3	39.4	37.8
Gross margin	(0.5)	(3.4)	(9.5)	(2.9)
Operating income (loss)	(5.1)	(8.3)	(23.0)	(19.3)
Real Estate Management And Development
Segment Reporting Information [Line Items]
Net sales	8.7	10.3	15.8	28.1
Cost of sales	7.3	8.0	12.9	21.3
Gross margin	1.4	2.3	2.9	6.8
Operating income (loss)	$ 0.3	$ 1.2	$ (5.1)	$ 2.6