Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements of Operations
Net sales	$ 137,907us-gaap_SalesRevenueGoodsNet	$ 111,414us-gaap_SalesRevenueGoodsNet
Cost of goods sold	107,254us-gaap_CostOfGoodsSold	87,287us-gaap_CostOfGoodsSold
Gross profit	30,653us-gaap_GrossProfit	24,127us-gaap_GrossProfit
Selling and administrative expenses	22,251	18,025
Amortization expense	2,157us-gaap_AmortizationOfIntangibleAssets	1,141us-gaap_AmortizationOfIntangibleAssets
Interest expense	613us-gaap_InterestExpense	123us-gaap_InterestExpense
Interest income	(57)us-gaap_InvestmentIncomeInterest	(144)us-gaap_InvestmentIncomeInterest
Equity in income of nonconsolidated investment	(173)	(204)
Other income	(803)us-gaap_OtherNonoperatingIncomeExpense	(135)us-gaap_OtherNonoperatingIncomeExpense
Total Operating Expenses	23,988fstr_TotalOperatingExpenses	18,806fstr_TotalOperatingExpenses
Income before income taxes	6,665	5,321
Income tax expense	2,380us-gaap_IncomeTaxExpenseBenefit	1,672us-gaap_IncomeTaxExpenseBenefit
Net income	$ 4,285us-gaap_NetIncomeLoss	$ 3,649us-gaap_NetIncomeLoss
Basic earnings per common share:
Basic earnings per common share	$ 0.42us-gaap_EarningsPerShareBasic	$ 0.36us-gaap_EarningsPerShareBasic
Diluted earnings per common share:
Diluted earnings per common share	$ 0.41us-gaap_EarningsPerShareDiluted	$ 0.35us-gaap_EarningsPerShareDiluted
Dividends paid per common share	$ 0.04	$ 0.03

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. This item also represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment.

No definition available.