<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM FORM 10-K
FINANCIAL STATEMENTS FILED FOR THE PERIODS ENDING DEC. 31, 1995, MARCH 31, 1996,
JUNE 30, 1996, SEPTEMBER 30, 1996 AND DECEMBER 31, 1996 AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<RESTATED> 
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>                     <C>                     <C>
<C>
<PERIOD-TYPE>                   12-MOS                   3-MOS                   6-MOS                   9-MOS
12-MOS
<FISCAL-YEAR-END>                          DEC-31-1995             DEC-31-1996             DEC-31-1996             DEC-31-1996
             DEC-31-1996
<PERIOD-START>                             JAN-01-1995             JAN-01-1996             JAN-01-1996             JAN-01-1996
             JAN-01-1996
<PERIOD-END>                               DEC-31-1995             MAR-31-1996             JUN-30-1996             SEP-30-1996
             DEC-31-1996
<CASH>                                          10,044                  21,121                   5,236                   7,275
                   7,089
<SECURITIES>                                    28,299                  16,026                  24,509                  31,384
                  33,440
<RECEIVABLES>                                   19,980                  30,625                  33,526                  36,264
                  28,728
<ALLOWANCES>                                         0                       0                       0                       0
                       0
<INVENTORY>                                      1,390                   9,626                   9,177                   8,661
                   1,462
<CURRENT-ASSETS>                                66,753                  84,006                  79,199                  91,605
                  79,391
<PP&E>                                          33,604                  60,328                  59,132                  59,410
                  40,033
<DEPRECIATION>                                  22,590                  43,638                  43,096                  43,337
                  29,017
<TOTAL-ASSETS>                                 155,292                 165,338                 168,626                 172,852
                 175,240
<CURRENT-LIABILITIES>                           17,166                  24,038                  22,622                  26,063
                  19,030
<BONDS>                                            579                     195                      68                      37
                       0
<PREFERRED-MANDATORY>                                0                       0                       0                       0
                       0
<PREFERRED>                                          0                       0                       0                       0
                       0
<COMMON>                                           645                     646                     650                     693
                     716
<OTHER-SE>                                     133,818                 136,639                 141,616                 144,097
                 153,480
<TOTAL-LIABILITY-AND-EQUITY>                   155,292                 165,338                 168,626                 172,852
                 175,240
<SALES>                                              0                       0                       0                       0
                       0
<TOTAL-REVENUES>                               103,567                  37,646                  75,421                 110,474
                 100,248
<CGS>                                                0                       0                       0                       0
                       0
<TOTAL-COSTS>                                   75,529                  26,946                  51,832                  76,831
                  74,434
<OTHER-EXPENSES>                                13,979                   6,216                  13,264                  35,610
                  31,511
<LOSS-PROVISION>                                     0                       0                       0                       0
                       0
<INTEREST-EXPENSE>                                 428                       0                       0                       0
                     285
<INCOME-PRETAX>                                 18,394                   5,214                  11,836                     608
                 (2,175)
<INCOME-TAX>                                     7,362                   2,106                   4,735                   4,624
                 (3,437)
<INCOME-CONTINUING>                             11,032                   3,108                   7,107                 (4,016)
                 (5,612)
<DISCONTINUED>                                   (337)                       0                       0                       0
                   4,246
<EXTRAORDINARY>                                      0                       0                       0                       0
                       0
<CHANGES>                                            0                       0                       0                       0
                       0
<NET-INCOME>                                    10,695                   3,108                   7,107                 (4,016)
                 (1,366)
<EPS-PRIMARY>                                     1.69                     .48                    1.10                   (.58)
                   (.21)
<EPS-DILUTED>                                     1.63                     .47                    1.07                   (.61)
                   (.21)
        

</TABLE>