Borrowings (Narrative) (Details) In Thousands, unless otherwise specified					12 Months Ended			12 Months Ended
	Dec. 31, 2013 Letter of Credit [Member] USD ($)	Dec. 31, 2012 Letter of Credit [Member] USD ($)	May 31, 2011 Prior Revolving Credit Facility [Member] USD ($)	May 31, 2011 Prior Credit Facility Term Loan [Member] USD ($)	Dec. 31, 2013 PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania [Member] Revolving Credit Facility [Member] USD ($)	Dec. 31, 2012 PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania [Member] Revolving Credit Facility [Member] USD ($)	Dec. 31, 2013 PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania [Member] Revolving Credit Facility Available To Canadian Borrowers [Member] USD ($)	Dec. 31, 2013 NatWest Bank [Member] Foreign Line of Credit [Member] USD ($)	Dec. 31, 2013 NatWest Bank [Member] Foreign Line of Credit [Member] GBP (£)	Dec. 31, 2012 NatWest Bank [Member] Foreign Line of Credit [Member] USD ($)	Dec. 31, 2013 NatWest Bank Outstanding Guarantees [Member] Foreign Line of Credit [Member] USD ($)	Dec. 31, 2012 NatWest Bank Outstanding Guarantees [Member] Foreign Line of Credit [Member] USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Initiation Date					May 02, 2011
Line of Credit Facility, Maximum Borrowing Capacity			$ 90,000	$ 20,000	$ 125,000		$ 15,000	$ 2,484	£ 1,500
Line of Credit Facility, Description					On May 2, 2011, the Company, its domestic subsidiaries, and certain of its Canadian subsidiaries entered into a new $125,000 Revolving Credit Facility Credit Agreement (Credit Agreement) with PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania. This Credit Agreement replaced a prior revolving credit facility with a maximum credit line of $90,000 and a $20,000 term loan. The Credit Agreement provides for a five-year, unsecured revolving credit facility that permits borrowing up to $125,000 for the U.S. borrowers and a sublimit of the equivalent of $15,000 U.S. dollars that is available to the Canadian borrowers. Provided no event of default exists, the Credit Agreement contains a provision that provides for an increase in the revolver facility of $50,000 that can be allocated to existing or new lenders if the Company's borrowing requirements should increase. The Credit Agreement includes a sublimit of $20,000 for the issuance of trade and standby letters of credit			A subsidiary of the Company has a working capital facility with NatWest Bank for its United Kingdom operations which includes an overdraft availability of £1,500 pounds sterling (approximately $2,484 at December 31, 2013). This credit facility supports the subsidiary's working capital requirements and is collateralized by substantially all of the assets of its United Kingdom operations	A subsidiary of the Company has a working capital facility with NatWest Bank for its United Kingdom operations which includes an overdraft availability of £1,500 pounds sterling (approximately $2,484 at December 31, 2013). This credit facility supports the subsidiary's working capital requirements and is collateralized by substantially all of the assets of its United Kingdom operations
Line of Credit Facility, Borrowing Capacity, Description					The Credit Agreement provides for a five-year, unsecured revolving credit facility that permits borrowing up to $125,000 for the U.S. borrowers and a sublimit of the equivalent of $15,000 U.S. dollars that is available to the Canadian borrowers.
Line of Credit Facility, Provision for Increase in Capacity					50,000
Line of Credit Facility, Capacity Available for Trade Purchases					20,000
Line of Credit Facility, Interest Rate Description					Borrowings under the Credit Agreement will bear interest at rates based upon either the base rate or LIBOR-based rate plus applicable margins. Applicable margins are dictated by the ratio of the Company's indebtedness less cash on hand in excess of $15,000 to the Company's consolidated EBITDA, as defined in the underlying Credit Agreement. The base rate is the highest of (a) PNC Bank's prime rate, (b) the Federal Funds Rate plus 0.50% or (c) the daily LIBOR rate, as defined in the underlying Credit Agreement, plus 1.00%. The base rate spread ranges from 0.00% to 1.00%. LIBOR-based rates are determined by dividing the published LIBOR rate by a number equal to 1.00 minus the percentage prescribed by the Federal Reserve for determining the maximum reserve requirements with respect to any Eurocurrency funding by banks on such day. The LIBOR-based rate spread ranges from 1.00% to 2.00%.			. The interest rate on this facility is the financial institution's base rate plus 1.50%.	. The interest rate on this facility is the financial institution's base rate plus 1.50%.
Line of Credit Facility, Covenant Terms					The Credit Agreement includes two financial covenants: (a) the Leverage Ratio, defined as the Company's Indebtedness less cash on hand in excess of $15,000 divided by the Company's consolidated EBITDA, which must not exceed 3.00 to 1.00 and (b) Minimum Interest Coverage, defined as consolidated EBITDA less Capital Expenditures divided by consolidated interest expense, which must be no less than 3.00 to 1.00.
Line of Credit Facility, Dividend Restrictions					The Credit Agreement permits the Company to pay dividends and distributions and make redemptions with respect to its stock provided no event of default or potential default (as defined in the Credit Agreement) has occurred prior to or after giving effect to the dividend, distribution, or redemption. Dividends, distributions, and redemptions are capped at $15,000 per year when funds are drawn on the facility. If no drawings on the facility exist, dividends, distributions, and redemptions in excess of $15,000 per year are subjected to a limitation of $75,000 in aggregate. The $75,000 aggregate limitation also includes certain loans, investments, and acquisitions. The Company is permitted to acquire the stock or assets of other entities with limited restrictions provided that the Leverage Ratio does not exceed 2.50 to 1.00 after giving effect to the acquisition.
Line of Credit Facility, Amount Outstanding	814	1,171			0	0		0			60	61
Line of Credit Facility, Current Borrowing Capacity					$ 124,186	$ 123,829		$ 2,424		$ 2,376
Line of Credit Facility, Collateral								This credit facility supports the subsidiary's working capital requirements and is collateralized by substantially all of the assets of its United Kingdom operations.	This credit facility supports the subsidiary's working capital requirements and is collateralized by substantially all of the assets of its United Kingdom operations.
Line of Credit Facility, Expiration Date								Jul. 31, 2014	Jul. 31, 2014
Line of Credit Facility, Asset Restrictions					Other restrictions exist at all times including, but not limited to, limitation of the Company's sale of assets, other indebtedness incurred by either the borrowers or the non-borrower subsidiaries of the Company, guaranties, and liens. On July 9, 2012, the Company amended the Credit Agreement to increase the limitation of the Company's sale of assets from $10,000 to $25,000.
Line of Credit Facility, Covenant Compliance					As of December 31, 2013, the Company was in compliance with the Credit Agreement's covenants			The United Kingdom loan agreements contain certain financial covenants that require that subsidiary to maintain senior interest and cash flow coverage ratios. The subsidiary was in compliance with these financial covenants as of December 31, 2013	The United Kingdom loan agreements contain certain financial covenants that require that subsidiary to maintain senior interest and cash flow coverage ratios. The subsidiary was in compliance with these financial covenants as of December 31, 2013