Basis of Presentation and Significant Accounting Policies - (Details Textual) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Customers Service_Center	Dec. 31, 2011	Dec. 31, 2010
Accounting Policies [Line Items]
Undistributed Earnings of Foreign Subsidiaries	$ 83,352
Service centers	49
Joint venture ownership percentage	50.00%
Sales revenue not recognized at shipment as a percentage of total sales, amount less than	3.00%
Shipping and handling costs	36,585	35,214	31,067
maximum maturity of investments to be considered cash equivalent	90 days
Percentage of LIFO inventory	80.00%
Amount current replacement cost of inventory costs exceeds book value	139,940	138,882
LIFO liquidation			12,500
Depreciation	$ 14,024	$ 13,605	$ 13,578
Percentage tax benefit recognized on dividends declared, joint venture subsidiaries	80.00%
Outstanding common stock equivalents	0	0	0
Excluded outstanding share-based awards having an anti-dilutive effect	994	757	471
Percent of participating securities, which represent certain non-vested shares	1.00%	1.00%	1.00%
Concentration risk, net sales, sales to customer excess 3 percent	0
Number of trading days preceeding grant date from which closing stock price used to determine exercise price, 2010 grants, alternate valuation method			10 days
Weighted average forfeiture rate	33.00%
Measurement period for targeted goals under the long-term compensation plan	3 years
Customer Concentration Risk
Accounting Policies [Line Items]
Concentration risk by concentration risk type	3.00%
Geographic Concentration Risk
Accounting Policies [Line Items]
Concentration risk by concentration risk type	78.00%
Convertible Debt Securities
Accounting Policies [Line Items]
Excluded outstanding share-based awards having an anti-dilutive effect	1,416	1,734
Point where convertible notes become dilutive
Accounting Policies [Line Items]
Stock conversion price, per share, convertible notes	$ 10.28
Dillutive effect if convertible notes become dillutive | Convertible Debt Securities
Accounting Policies [Line Items]
Outstanding common stock equivalents	5,600
Limited Liability Company
Accounting Policies [Line Items]
Joint venture ownership percentage	50.00%
Non-compete agreements
Accounting Policies [Line Items]
Intangible assets useful lives	3 years
Developed technology
Accounting Policies [Line Items]
Intangible assets useful lives	3 years
Minimum | Stock Options
Accounting Policies [Line Items]
Contractual period for options granted in 2010			8 years
Minimum | Customer relationships
Accounting Policies [Line Items]
Intangible assets useful lives	4 years
Minimum | Trade name
Accounting Policies [Line Items]
Intangible assets useful lives	1 year
Maximum | Stock Option
Accounting Policies [Line Items]
Contractual period for options granted in 2010			10 years
Maximum | Customer relationships
Accounting Policies [Line Items]
Intangible assets useful lives	12 years
Maximum | Trade name
Accounting Policies [Line Items]
Intangible assets useful lives	10 years
North America
Accounting Policies [Line Items]
Service centers	44
Europe
Accounting Policies [Line Items]
Service centers	4
Asia
Accounting Policies [Line Items]
Service centers	1
Executives and Employees | Minimum | Stock Options and Restricted Stock
Accounting Policies [Line Items]
Contractual life for options and restricted stock	1 year
Executives and Employees | Maximum | Stock Options and Restricted Stock
Accounting Policies [Line Items]
Contractual life for options and restricted stock	5 years
Director | Maximum | Stock Options and Restricted Stock
Accounting Policies [Line Items]
Contractual life for options and restricted stock	3 years