Borrowings (Narrative) (Details) In Thousands, unless otherwise specified			9 Months Ended			9 Months Ended
	Sep. 30, 2014 PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania [Member] Letter of Credit [Member] USD ($)	Sep. 30, 2014 PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania [Member] Foreign Line of Credit [Member] USD ($)	Sep. 30, 2014 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 ($)	Dec. 31, 2013 PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania [Member] Revolving Credit Facility [Member] USD ($)	Sep. 30, 2014 PNC Bank, N.A., Bank of America, N.A., Wells Fargo Bank, N.A. and Citizens Bank of Pennsylvania [Member] Prior Revolving Credit Facility [Member] USD ($)	Sep. 30, 2014 NatWest Bank [Member] Foreign Line of Credit [Member] USD ($)	Sep. 30, 2014 NatWest Bank [Member] Foreign Line of Credit [Member] GBP (£)	Sep. 30, 2014 NatWest Bank Outstanding Guarantees [Member] Foreign Line of Credit [Member] USD ($)	Dec. 31, 2013 NatWest Bank Outstanding Guarantees [Member] Foreign Line of Credit [Member] USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Initiation Date			Sep. 23, 2014
Line of Credit Facility, Maximum Borrowing Capacity		$ 25,000	$ 200,000		$ 125,000	$ 2,432	£ 1,500
Debt Instrument, Term			5 years
Line of Credit Facility, Borrowing Capacity, Description			The Amended Credit Agreement provides for a five-year, unsecured revolving credit facility that permits borrowing up to $200,000 for the U.S. borrowers and a sublimit of the equivalent of $25,000 U.S. dollars that is available to the Canadian borrowers. The Amended Credit Agreement also modifies the accordion feature in the prior revolving credit facility which permitted a maximum increase of $50,000. The Amended Credit Agreement's accordion feature permits the Company to increase the available revolving borrowings under the facility by up to an additional $100,000 subject to the Company's receipt of increased commitments from existing lenders or new commitments from new lenders and to certain conditions being satisfied. The Amended Credit Agreement also increases the sublimit for the issuance of trade and standby letters of credit from $20,000 to $30,000.
Line of Credit Facility, Interest Rate Description			Borrowings under the Amended Credit Agreement will bear interest at rates based upon either the base rate or Euro-rate plus applicable margins. Applicable margins are dictated by the ratio of the Company's indebtedness less cash on hand to the Company's consolidated EBITDA, as defined in the underlying Amended 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 Euro-rate (as defined in the Amended Credit Agreement) plus 1.00%. The base rate and Euro-rate spreads range from 0.00% to 1.00% and 1.00% to 2.00%, respectively.			. 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 Amended Credit Agreement includes two financial covenants: (a) 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 3.25 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.			The United Kingdom loan agreements contain certain financial covenants that require that subsidiary to maintain senior interest and cash flow coverage ratios.	The United Kingdom loan agreements contain certain financial covenants that require that subsidiary to maintain senior interest and cash flow coverage ratios.
Line of Credit Facility, Dividend Restrictions			Dividends, distributions, and redemptions are capped at $25,000 per year when funds are drawn on the facility. If no drawings on the facility exist, dividends, distributions, and redemptions in excess of $25,000 per year are subjected to a limitation of $75,000 in the aggregate. The $75,000 aggregate limitation also permits certain loans, investments, and acquisitions.
Line of Credit Facility, Amount Outstanding	713		0	0		0		31	60
Line of Credit Facility, Current Borrowing Capacity			$ 199,287			$ 2,401
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, 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, guarantees, and liens.
Line of Credit Facility, Covenant Compliance			As of September 30, 2014, the Company was in compliance with the Amended Credit Agreement's covenants.			The subsidiary was in compliance with these financial covenants as of September 30, 2014.	The subsidiary was in compliance with these financial covenants as of September 30, 2014.