Debt	3 Months Ended
Mar. 31, 2018
Debt Disclosure [Abstract]
Debt	Debt Credit Facilities The Company has revolving lines of credit with various banks in the United States and Europe. Total available credit at March 31, 2018, was $304.2 million including revolving credit lines and an irrevocable standby letter of credit in support of various insurance deductibles. The Company’s primary credit facility is a revolving line of credit with $300 million in available credit. On July 25, 2016, the Company entered into a second amendment (the "Amendment") to the credit facility. For additional information about the Amendment, see the Company's Current Report on Form 8-K dated July 28, 2016. As amended, this credit facility will expire on July 23, 2021. Amounts borrowed under this credit facility bear interest at an annual rate equal to either, at the Company’s option, (a) the rate for Eurocurrency deposits for the corresponding deposits of U.S. dollars appearing on Reuters LIBOR1screen page (the “LIBOR Rate”), adjusted for any reserve requirement in effect, plus a spread of 0.60% to 1.45%, determined quarterly based on the Company’s leverage ratio (at March 31, 2018, the LIBOR Rate was 1.80%), or (b) a base rate, plus a spread of 0.00% to 0.45%, determined quarterly based on the Company’s leverage ratio. The base rate is defined in a manner such that it will not be less than the LIBOR Rate. The Company will pay fees for standby letters of credit at an annual rate equal to the applicable spread described above, and will pay market-based fees for commercial letters of credit. The Company is required to pay an annual facility fee of 0.15% to 0.30% of the available commitments under the credit facility, regardless of usage, with the applicable fee determined on a quarterly basis based on the Company’s leverage ratio. The Company’s unused borrowing capacity under other revolving credit lines and a term note totaled $4.2 million at March 31, 2018. The other revolving credit lines and the term note charge interest ranging from 0.47% to 11.50%, currently have maturity dates from July 2018 to December 2018. The Company had no outstanding debt balance as of March 31, 2018 and 2017, and December 31, 2017, respectively. The Company was in compliance with its financial covenants at March 31, 2018. Capital Lease Obligations In 2017, the Company entered into two four-year lease agreements for certain office equipment with Cisco Systems Capital Corporation for a total of approximately $4.4 million, which was recorded in fixed assets as capital lease obligations. These capital lease obligations are included in current liabilities and other long-term liabilities in the accompanying condensed consolidated balance sheets. The interest rates for these two capital leases are 2.89% and 3.50%, respectively, and the two leases will mature in May 2021 and July 2021, respectively. As of March 31, 2018, the current portion of the outstanding liability for the leased equipment was approximately $1.1 million and the long-term portion was approximately $2.4 million.

Debt

Credit Facilities

The Company has revolving lines of credit with various banks in the United States and Europe. Total available credit at March 31, 2018, was $304.2 million including revolving credit lines and an irrevocable standby letter of credit in support of various insurance deductibles.

The Company’s primary credit facility is a revolving line of credit with $300 million in available credit. On July 25, 2016, the Company entered into a second amendment (the "Amendment") to the credit facility. For additional information about the Amendment, see the Company's Current Report on Form 8-K dated July 28, 2016. As amended, this credit facility will expire on July 23, 2021. Amounts borrowed under this credit facility bear interest at an annual rate equal to either, at the Company’s option, (a) the rate for Eurocurrency deposits for the corresponding deposits of U.S. dollars appearing on Reuters LIBOR1screen page (the “LIBOR Rate”), adjusted for any reserve requirement in effect, plus a spread of 0.60% to 1.45%, determined quarterly based on the Company’s leverage ratio (at March 31, 2018, the LIBOR Rate was 1.80%), or (b) a base rate, plus a spread of 0.00% to 0.45%, determined quarterly based on the Company’s leverage ratio. The base rate is defined in a manner such that it will not be less than the LIBOR Rate. The Company will pay fees for standby letters of credit at an annual rate equal to the applicable spread described above, and will pay market-based fees for commercial letters of credit. The Company is required to pay an annual facility fee of 0.15% to 0.30% of the available commitments under the credit facility, regardless of usage, with the applicable fee determined on a quarterly basis based on the Company’s leverage ratio. The Company’s unused borrowing capacity under other revolving credit lines and a term note totaled $4.2 million at March 31, 2018. The other revolving credit lines and the term note charge interest ranging from 0.47% to 11.50%, currently have maturity dates from July 2018 to December 2018. The Company had no outstanding debt balance as of March 31, 2018 and 2017, and December 31, 2017, respectively. The Company was in compliance with its financial covenants at March 31, 2018.

Capital Lease Obligations

In 2017, the Company entered into two four-year lease agreements for certain office equipment with Cisco Systems Capital Corporation for a total of approximately $4.4 million, which was recorded in fixed assets as capital lease obligations. These capital lease obligations are included in current liabilities and other long-term liabilities in the accompanying condensed consolidated balance sheets. The interest rates for these two capital leases are 2.89% and 3.50%, respectively, and the two leases will mature in May 2021 and July 2021, respectively.

As of March 31, 2018, the current portion of the outstanding liability for the leased equipment was approximately $1.1 million and the long-term portion was approximately $2.4 million.