<ARTICLE> 5
<MULTIPLIER> 1,000
       
                                                  
<PERIOD-TYPE>                   6-MOS                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1996
<PERIOD-START>                             JAN-01-1997             JAN-01-1996
<PERIOD-END>                               JUN-30-1997             JUN-30-1996
<CASH>                                          29,883                   7,315
<SECURITIES>                                    10,081                  18,572
<RECEIVABLES>                                   46,608                  36,281
<ALLOWANCES>                                     1,510                   1,529
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<CURRENT-ASSETS>                                92,944                  68,753
<PP&E>                                          42,755                  31,663
<DEPRECIATION>                                  14,485                  12,022
<TOTAL-ASSETS>                                 278,829                 183,200
<CURRENT-LIABILITIES>                           37,575                  29,121
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<PREFERRED>                                          0                       0
<COMMON>                                           259                     228
<OTHER-SE>                                     232,991                 146,753
<TOTAL-LIABILITY-AND-EQUITY>                   278,829                 183,200
<SALES>                                              0                       0
<TOTAL-REVENUES>                               109,540                  88,717
<CGS>                                                0                       0
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<INTEREST-EXPENSE>                                 413                     440
<INCOME-PRETAX>                                 16,357                   8,154
<INCOME-TAX>                                     6,215                   3,343
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<NET-INCOME>                                    10,142                   4,811
<EPS-PRIMARY>                                     0.40                    0.21
<EPS-DILUTED>                                     0.38                    0.19