<ARTICLE> 5
<MULTIPLIER> 1,000
       
                                                  
<PERIOD-TYPE>                   9-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1996
<PERIOD-START>                             JAN-01-1997             JAN-01-1996
<PERIOD-END>                               SEP-30-1997             SEP-30-1996
<CASH>                                          29,624                   8,957
<SECURITIES>                                    80,523                  16,416
<RECEIVABLES>                                   53,950                  34,681
<ALLOWANCES>                                     1,465                   1,427
<INVENTORY>                                      5,786                   3,994
<CURRENT-ASSETS>                               172,298                  66,864
<PP&E>                                          50,819                  33,834
<DEPRECIATION>                                  16,145                  13,402
<TOTAL-ASSETS>                                 368,616                 184,324
<CURRENT-LIABILITIES>                           39,376                  27,895
<BONDS>                                              0                       0
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                           289                     228
<OTHER-SE>                                     326,293                 149,550
<TOTAL-LIABILITY-AND-EQUITY>                   368,616                 184,324
<SALES>                                              0                       0
<TOTAL-REVENUES>                               168,003                 130,196
<CGS>                                                0                       0
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<OTHER-EXPENSES>                                     0                       0
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<INTEREST-EXPENSE>                                 426                     637
<INCOME-PRETAX>                                 27,937                  15,393
<INCOME-TAX>                                    10,268                   6,240
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<CHANGES>                                            0                       0
<NET-INCOME>                                    17,669                   9,153
<EPS-PRIMARY>                                     0.67                    0.40
<EPS-DILUTED>                                     0.64                    0.36