Debt	12 Months Ended
Dec. 31, 2013
Debt Disclosure [Abstract]
Debt	Debt Revolving Credit Facility In 2011 we entered into a revolving credit facility with a syndicate of seven banks led by JPMorgan Chase. This facility, which matures in September 2016, has a total commitment of $200 million and is governed by financial and non-financial covenants, including a leverage ratio of not greater than 3.00 to 1.00, an interest coverage ratio of not less than 3.00 to 1.00, and a requirement to maintain a certain level of tangible assets in our U.S. entities. Our marginal borrowing costs on this facility are based on a floating base rate (LIBOR) plus a spread, which ranges from 1.25% to 2.00%, depending on our degree of financial leverage. We also pay a fee on the committed but unused amount of the facility, which ranges from 0.25% to 0.40%, also depending on our degree of financial leverage. The agreement further includes an accordion feature, which allows for an increase in the commitments to a total of $400 million under the same terms and conditions, subject to credit approval of the banking syndicate. Since entering into this credit facility, we have not had any borrowings outstanding except for letters of credit, which were insignificant at the end of 2013. Therefore, as of December 31, 2013, we had $200 million available for future borrowings. As of the same date, we were in compliance with all of the covenants under our facility. Notes Payable We have entered into various financing arrangements with equipment and software vendors. As of December 31, 2013, the total amount financed under these relationships was $2.0 million with various terms extending to July 2015 and stated interest rates ranging from 0.0% to 1.7%. For arrangements with below-market interest rates, we impute an interest charge based on our average borrowing rate. The weighted-average effective interest rate of the various arrangements with third-party vendors was 5.3% as of December 31, 2013.

Debt

Revolving Credit Facility

In 2011 we entered into a revolving credit facility with a syndicate of seven banks led by JPMorgan Chase. This facility, which matures in September 2016, has a total commitment of $200 million and is governed by financial and non-financial covenants, including a leverage ratio of not greater than 3.00 to 1.00, an interest coverage ratio of not less than 3.00 to 1.00, and a requirement to maintain a certain level of tangible assets in our U.S. entities. Our marginal borrowing costs on this facility are based on a floating base rate (LIBOR) plus a spread, which ranges from 1.25% to 2.00%, depending on our degree of financial leverage. We also pay a fee on the committed but unused amount of the facility, which ranges from 0.25% to 0.40%, also depending on our degree of financial leverage. The agreement further includes an accordion feature, which allows for an increase in the commitments to a total of $400 million under the same terms and conditions, subject to credit approval of the banking syndicate.

Since entering into this credit facility, we have not had any borrowings outstanding except for letters of credit, which were insignificant at the end of 2013. Therefore, as of December 31, 2013, we had $200 million available for future borrowings. As of the same date, we were in compliance with all of the covenants under our facility.

Notes Payable

We have entered into various financing arrangements with equipment and software vendors. As of December 31, 2013, the total amount financed under these relationships was $2.0 million with various terms extending to July 2015 and stated interest rates ranging from 0.0% to 1.7%. For arrangements with below-market interest rates, we impute an interest charge based on our average borrowing rate. The weighted-average effective interest rate of the various arrangements with third-party vendors was 5.3% as of December 31, 2013.