CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Net sales	$ 142,015us-gaap_SalesRevenueGoodsNet	$ 82,646us-gaap_SalesRevenueGoodsNet
Cost of sales	114,890us-gaap_CostOfGoodsSold	68,576us-gaap_CostOfGoodsSold
Gross profit	27,125us-gaap_GrossProfit	14,070us-gaap_GrossProfit
Selling, general and administrative expense	17,608	11,189
Restructuring charges	158us-gaap_RestructuringCharges	0us-gaap_RestructuringCharges
Income from operations	9,359us-gaap_OperatingIncomeLoss	2,881us-gaap_OperatingIncomeLoss
Interest expense	(2,179)us-gaap_InterestExpense	(30)us-gaap_InterestExpense
Interest income and other, net	402us-gaap_OtherNonoperatingIncome	51us-gaap_OtherNonoperatingIncome
Earnings before provision for income taxes	7,582	2,902
Provision for income taxes	2,014us-gaap_IncomeTaxExpenseBenefit	399us-gaap_IncomeTaxExpenseBenefit
Net earnings available to common stockholders	5,568us-gaap_NetIncomeLoss	2,503us-gaap_NetIncomeLoss
Class A [Member]
Net earnings available to common stockholders	970	442
Net earnings per common share:
Common share - basic and diluted (in dollars per share)	$ 0.45	$ 0.20
Weighted-average number of shares outstanding:
Common share - basic and diluted (in shares)	2,175	2,175
Dividends paid per common share:
Common share (in dollars per share)	$ 0.06	$ 0.06
Class B [Member]
Net earnings available to common stockholders	$ 4,598	$ 2,061
Net earnings per common share:
Common share - basic and diluted (in dollars per share)	$ 0.48	$ 0.22
Weighted-average number of shares outstanding:
Common share - basic and diluted (in shares)	9,670	9,335
Dividends paid per common share:
Common share (in dollars per share)	$ 0.07	$ 0.07

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