<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM FORM 10-Q
FINANCIAL STATEMENTS FILED FOR THE PERIODS ENDING MARCH 31, 1997, JUNE 30, 1997
AND SEPTEMBER 30, 1997 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED> 
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-START>                             JAN-01-1997             JAN-01-1997             JAN-01-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997
<CASH>                                             501                   8,420                  15,148
<SECURITIES>                                    30,588                  27,498                  24,067
<RECEIVABLES>                                   30,525                  27,403                  28,217
<ALLOWANCES>                                         0                       0                       0
<INVENTORY>                                      1,324                   1,363                   1,685
<CURRENT-ASSETS>                                71,099                  70,500                  73,930
<PP&E>                                          40,692                  41,591                  39,936
<DEPRECIATION>                                  30,195                  31,492                  28,946
<TOTAL-ASSETS>                                 177,998                 172,286                 175,956
<CURRENT-LIABILITIES>                           22,984                  21,218                  21,779
<BONDS>                                             39                       0                       0
<PREFERRED-MANDATORY>                                0                       0                       0
<PREFERRED>                                          0                       0                       0
<COMMON>                                           719                     719                     719
<OTHER-SE>                                     152,326                 148,488                 151,447
<TOTAL-LIABILITY-AND-EQUITY>                   177,998                 172,286                 175,956
<SALES>                                              0                       0                       0
<TOTAL-REVENUES>                                25,379                  53,134                  79,455
<CGS>                                                0                       0                       0
<TOTAL-COSTS>                                   18,019                  36,637                  55,622
<OTHER-EXPENSES>                                 5,218                  10,790                  15,282
<LOSS-PROVISION>                                     0                       0                       0
<INTEREST-EXPENSE>                                   0                       0                       0
<INCOME-PRETAX>                                  3,099                   7,706                  11,594
<INCOME-TAX>                                     1,233                   3,074                   4,639
<INCOME-CONTINUING>                              1,866                   4,632                   6,955
<DISCONTINUED>                                   (787)                   (781)                   (540)
<EXTRAORDINARY>                                      0                       0                       0
<CHANGES>                                            0                       0                       0
<NET-INCOME>                                     1,079                   3,851                   6,415
<EPS-PRIMARY>                                      .15                     .55                     .92
<EPS-DILUTED>                                      .15                     .54                     .90
        

</TABLE>