Business Segments The Company, which aggregates its operating segments based on the nature of services, has three reportable segments: temporary and consultant staffing, permanent placement staffing, and risk consulting and internal audit services. The temporary and consultant staffing segment provides specialized staffing in the accounting and finance, administrative and office, information technology, legal, advertising, marketing and web design fields. The permanent placement staffing segment provides full-time personnel in the accounting, finance, administrative and office, and information technology fields. The risk consulting and internal audit services segment provides business and technology risk consulting and internal audit services. The accounting policies of the segments are set forth in Note A"Summary of Significant Accounting Policies" in the Companys Annual Report on Form 10-K for the year ended December 31, 2017 . The Company evaluates performance based on income from operations before net interest income, intangible asset amortization expense, and income taxes. The following table provides a reconciliation of revenue and operating income by reportable segment to consolidated results for the three months ended March 31, 2018 and 2017 (in thousands): Three Months Ended March 31, 2018 2017 Net service revenues Temporary and consultant staffing $ 1,066,288 $ 987,606 Permanent placement staffing 121,400 103,633 Risk consulting and internal audit services 207,645 196,131 $ 1,395,333 $ 1,287,370 Operating income Temporary and consultant staffing $ 96,723 $ 90,371 Permanent placement staffing 22,379 18,302 Risk consulting and internal audit services 15,265 16,906 134,367 125,579 Amortization of intangible assets 463 301 Interest income, net (735 ) (223 ) Income before income taxes $ 134,639 $ 125,501