Business and Geographic Segments - Net Sales by Point of Origin and Point of Destination (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
Point Of Origin
Segment Reporting Information [Line Items]
Net sales									1,566.8	1,532.9	1,862.6
Point Of Destination
Segment Reporting Information [Line Items]
Net sales									1,566.8	1,532.9	1,862.6
United States | Point Of Origin
Segment Reporting Information [Line Items]
Net sales									866.7	841.9	993.7
Germany | Point Of Origin
Segment Reporting Information [Line Items]
Net sales									699.8	690.0	844.1
Canada | Point Of Origin
Segment Reporting Information [Line Items]
Net sales									257.7	216.9	252.3
Belgium | Point Of Origin
Segment Reporting Information [Line Items]
Net sales									187.4	198.8	249.3
Norway | Point Of Origin
Segment Reporting Information [Line Items]
Net sales									164.8	183.5	256.8
North America | Point Of Destination
Segment Reporting Information [Line Items]
Net sales									614.2	604.0	753.2
Europe | Point Of Destination
Segment Reporting Information [Line Items]
Net sales									698.2	700.9	883.6
Asia and other | Point Of Destination
Segment Reporting Information [Line Items]
Net sales									254.4	228.0	225.8
Geography Eliminations | Point Of Origin
Segment Reporting Information [Line Items]
Net sales									$ (609.6)	$ (598.2)	$ (733.6)