
<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1998
<PERIOD-END>                               MAR-31-1997             MAR-31-1998
<CASH>                                           9,101                   7,894
<SECURITIES>                                    71,464                  67,556
<RECEIVABLES>                                   39,499                  48,356
<ALLOWANCES>                                     1,611                   2,737
<INVENTORY>                                          0                       0
<CURRENT-ASSETS>                               121,193                 125,535
<PP&E>                                          40,700                  84,189
<DEPRECIATION>                                  13,641                  25,519
<TOTAL-ASSETS>                                 153,631                 203,747
<CURRENT-LIABILITIES>                           29,890                  48,052
<BONDS>                                          9,371                   8,434
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                           571                     595
<OTHER-SE>                                     113,236                 145,449
<TOTAL-LIABILITY-AND-EQUITY>                   153,631                 203,747
<SALES>                                         61,258                  80,244
<TOTAL-REVENUES>                                61,258                  80,244
<CGS>                                           38,887                  51,856
<TOTAL-COSTS>                                   52,694                  73,118
<OTHER-EXPENSES>                                 (905)                   (809)
<LOSS-PROVISION>                                     0                       0
<INTEREST-EXPENSE>                                 445                     302
<INCOME-PRETAX>                                  9,014                   7,633
<INCOME-TAX>                                     3,662                   3,081
<INCOME-CONTINUING>                              5,352                   4,552
<DISCONTINUED>                                       0                       0
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                     5,352                   4,552
<EPS-PRIMARY>                                     0.09                    0.08
<EPS-DILUTED>                                     0.09                    0.07
        

</TABLE>
