Business and Geographic Segments - Segment Operating Performance (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net sales	$ 407.9	$ 406.8	$ 398.6	$ 353.5	$ 324.8	$ 383.2	$ 408.8	$ 416.1	$ 1,566.8	$ 1,532.9	$ 1,862.6
Cost of sales									1,274.7	1,310.0	1,459.8
Gross margin	102.6	85.3	62.2	42.0	27.5	49.8	56.3	89.3	292.1	222.9	402.8
Operating income (loss)	$ 52.0	$ 29.7	$ 9.8	$ (10.3)	$ (24.9)	$ (5.0)	$ (10.1)	$ 34.6	81.2	(5.4)	170.2
Securities earnings									27.7	26.5	26.9
Insurance recoveries									0.4	3.7	10.4
General expenses, net									(43.1)	(39.6)	(38.8)
Interest expense									(63.2)	(59.0)	(56.7)
Income (loss) before income taxes									3.0	(73.8)	112.0
Depreciation and amortization									67.5	69.9	78.4
Capital expenditures									58.9	54.6	72.7
Operating Segment | Chemicals
Segment Reporting Information [Line Items]
Net sales									1,364.3	1,348.8	1,651.9
Cost of sales									1,109.2	1,158.5	1,304.6
Gross margin									255.1	190.3	347.3
Operating income (loss)									91.0	7.1	156.8
Depreciation and amortization									42.6	44.3	51.9
Capital expenditures									53.0	47.5	61.3
Operating Segment | Component Products
Segment Reporting Information [Line Items]
Net sales									108.9	109.0	103.9
Cost of sales									73.8	75.6	71.6
Gross margin									35.1	33.4	32.3
Operating income (loss)									15.6	14.0	13.6
Depreciation and amortization									3.7	3.5	3.5
Capital expenditures									3.2	4.2	2.8
Operating Segment | Waste Management
Segment Reporting Information [Line Items]
Net sales									47.4	45.0	66.5
Cost of sales									55.5	50.5	49.7
Gross margin									(8.1)	(5.5)	16.8
Operating income (loss)									(26.2)	(26.5)	(2.2)
Depreciation and amortization									18.3	19.3	20.3
Capital expenditures									0.7	1.7	4.5
Operating Segment | Real Estate Management And Development
Segment Reporting Information [Line Items]
Net sales									46.2	30.1	40.3
Cost of sales									36.2	25.4	33.9
Gross margin									10.0	4.7	6.4
Operating income (loss)									0.8		2.0
Depreciation and amortization									2.9	2.8	2.7
Capital expenditures									$ 2.0	$ 1.2	4.0
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Capital expenditures											$ 0.1