Debt (Senior Secured Credit Facility) (Terms, Guarantees and Covenants) (Narrative) (Details) - Credit Facility [Member]	12 Months Ended
	Dec. 31, 2014
Debt Instrument [Line Items]
Line of credit facility, description of variable rate	Outstanding revolving loans and the Term Loan under the Credit Facility bear interest, at the Company’s option, at a rate equal to either (a) a Eurocurrency Rate, as defined in the Credit Facility, plus a margin of 1.00% to 2.00% or (b) a Base Rate, plus a margin of 0.00% to 1.00%. The Base Rate equals the highest of (i) the Federal Funds Rate, as defined in the Credit Facility, plus 0.50%, (ii) Bank of America’s prime rate and (iii) the Eurocurrency Rate plus 1.00%
Line of credit facility, commitment fee description	The Company must also pay a commitment fee to the lenders of 0.20% to 0.40% on any unused availability under the Credit Facility.
Line of credit facility, collateral	The Credit Facility is guaranteed by certain subsidiaries of the Company (the “Guarantor Subsidiaries”) and the obligations under the Credit Facility are secured by substantially all of the Company’s and the Guarantor Subsidiaries’ respective assets, subject to certain exceptions. Under the Credit Facility, if the “Loan Party EBITDA,” as defined in the Credit Facility, as of the last four consecutive fiscal quarters does not represent at least 70% of the “Adjusted Consolidated EBITDA,” as defined in the Credit Facility, for such period, then the Company must designate additional subsidiaries as Guarantor Subsidiaries, and cause them to join the applicable guaranty and security agreements to the Credit Facility. Additionally, any domestic subsidiary with consolidated EBITDA of at least 15% of the Adjusted Consolidated EBITDA must become a Guarantor Subsidiary and join the applicable guaranty and security agreements.
Line of credit facility, covenant terms	The Credit Facility requires that the Company maintain a maximum consolidated leverage ratio, as defined in the Credit Facility, of 3.50 and a minimum consolidated interest coverage ratio, as defined in the Credit Facility, of 3.00; however, the Credit Facility provides that, for purposes of calculating the consolidated leverage ratio, funded indebtedness excludes the undrawn standby performance letters of credit. Additionally, subject to certain conditions, if a permitted acquisition or series of permitted acquisitions having consideration exceeding $50 million occurs during a fiscal quarter, the Company has the right to permit the consolidated leverage ratio to exceed 3.50 during such fiscal quarter and the subsequent two fiscal quarters so long as the consolidated leverage ratio does not exceed 3.75 at any time during such period. Such right may be exercised no more than two times during the term of the Credit Facility. Subject to customary exceptions, the Credit Facility limits the borrowers’ and the Guarantor Subsidiaries’ ability to engage in certain activities, including acquisitions, mergers and consolidations, debt incurrence, investments, capital expenditures, asset sales, debt prepayments, lien incurrence and the making of distributions or repurchases of capital stock. However, distributions payable solely in capital stock are permitted. The Credit Facility provides for customary events of default and carries cross-default provisions with the Company’s other significant debt instruments, including the Company’s indemnity agreement with its surety provider, as well as customary remedies upon an Event of Default, as defined in the Credit Facility, including the acceleration of repayment of outstanding amounts and other remedies with respect to the collateral securing the Credit Facility obligations.
Term Loan [Member]
Debt Instrument [Line Items]
Line of credit facility, accordion feature description	Under an “accordion” feature of the Credit Facility, the Company has the option to increase revolving commitments and/or establish additional term loan tranches in an aggregate amount of $250 million. These additional term loan tranches may, subject to certain terms and conditions described in the Credit Facility, rank equal or junior in respect of right of payment and/or collateral to the Credit Facility and may, subject to certain limitations described in the Credit Facility, have terms and pricing that differ from the Credit Facility.
Letters of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate description, letters of credit	Financial standby letters of credit and commercial letters of credit issued under the Credit Facility are subject to a letter of credit fee of 1.00% to 2.00%, and performance standby letters of credit are subject to a letter of credit fee of 0.50% to 1.00%.