Segment Reporting, Sales by Product Grouping (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Sales by product grouping [Abstract]
Net sales	$ 172,812	$ 184,007	$ 181,575	$ 166,784	$ 144,691	$ 155,264	$ 179,941	$ 162,987	$ 705,178	$ 642,883	$ 794,634
Sales by customers [Member]
Sales by product grouping [Abstract]
% of Sales (in hundredths)									37.80%	37.70%	36.50%
Sales by product grouping [Member]
Sales by product grouping [Abstract]
Net sales									705,178	642,883	794,634
% of Sales (in hundredths)									100.00%	100.00%	100.00%
Wheels [Member] | Sales by product grouping [Member]
Sales by product grouping [Abstract]
Net sales									402,146	364,614	414,340
% of Sales (in hundredths)									57.00%	56.70%	52.10%
Wheel end components and assemblies [Member] | Sales by product grouping [Member]
Sales by product grouping [Abstract]
Net sales									171,263	168,988	221,974
% of Sales (in hundredths)									24.30%	26.30%	27.90%
Ductile and gray iron castings [Member] | Sales by product grouping [Member]
Sales by product grouping [Abstract]
Net sales									$ 131,769	$ 109,281	$ 158,320
% of Sales (in hundredths)									18.70%	17.00%	20.00%