Summarized Balance Sheet Information of Reportable Segments (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 27.2	$ 35.7	$ 61.9
Trade accounts receivable, net	88.4	77.2
Inventories	118.2	101.2
Prepaid expenses, supplies and other current assets	24.6	24.7
Total current assets	286.8	271.8
Property, plant and equipment, net	289.2	301.5
Equity method investment	5.0
Identifiable intangible assets, net	12.5	15.1
Goodwill	42.2	104.3
Other noncurrent assets	9.8	8.2
TOTAL ASSETS	645.5	700.9
Current liabilities:
Trade payables	115.8	100.9
Accrued liabilities	46.4	51.8
Total current liabilities	164.5	155.1
Accrued pension benefits	42.0	38.0
Environmental liabilities	11.6	11.7
Other noncurrent liabilities	6.9	5.4
TOTAL LIABILITIES	586.1	536.6
RANA
Current assets:
Goodwill	33.6	95.4
RAEU
Current assets:
Goodwill	8.6	8.9
Operating Segments | RANA
Current assets:
Cash and cash equivalents	11.5	8.1
Trade accounts receivable, net	76.2	63.7
Financing receivable	0.0	0.0
Inventories	79.3	61.7
Prepaid expenses, supplies and other current assets	13.7	12.5
Total current assets	180.7	146.0
Property, plant and equipment, net	195.0	199.3
Equity method investment	5.0	0.0
Identifiable intangible assets, net	12.5	15.0
Goodwill	33.6	95.4
Other noncurrent assets	5.0	4.9
TOTAL ASSETS	431.8	460.6
Current liabilities:
Trade payables	73.8	58.1
Accrued liabilities	30.0	34.3
Total current liabilities	103.8	92.4
Accrued pension benefits	0.0	0.0
Environmental liabilities	11.6	11.7
Other noncurrent liabilities	4.5	4.1
TOTAL LIABILITIES	119.9	108.2
Operating Segments | RAEU
Current assets:
Cash and cash equivalents	5.7	7.2
Trade accounts receivable, net	12.2	13.5
Financing receivable	28.4	32.7
Inventories	38.9	38.5
Prepaid expenses, supplies and other current assets	6.4	6.8
Total current assets	91.6	98.7
Property, plant and equipment, net	94.2	102.2
Equity method investment	0.0	0.0
Identifiable intangible assets, net	0.0	0.0
Goodwill	8.6	8.9
Other noncurrent assets	3.5	1.9
TOTAL ASSETS	197.9	211.7
Current liabilities:
Trade payables	41.8	42.3
Accrued liabilities	13.4	14.6
Total current liabilities	55.2	56.9
Accrued pension benefits	42.0	38.0
Environmental liabilities	0.0	0.0
Other noncurrent liabilities	1.8	1.4
TOTAL LIABILITIES	$ 99.0	$ 96.3