Compensation Cost for Performance Share Units (Details) (Performance Shares, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total expense before income taxes	$ 3,220	$ 873
Income tax benefit	(1,081)	(280)
Total expense after income taxes	2,139	593
Cost of goods sold
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total expense before income taxes	0	0
Selling, general and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total expense before income taxes	$ 3,220	$ 873