
<TABLE> <S> <C>

<PAGE>
 
<ARTICLE> 5
<LEGEND>
This schedule contains summary financial information extracted from (identify
specific financial statements) and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<MULTIPLIER> 1,000
<CURRENCY> US
       
<S>                             <C>
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997
<PERIOD-START>                             JAN-01-1997
<PERIOD-END>                               SEP-30-1997
<EXCHANGE-RATE>                                    1.0
<CASH>                                          12,000
<SECURITIES>                                         0
<RECEIVABLES>                                   30,881
<ALLOWANCES>                                   (1,539)
<INVENTORY>                                          0
<CURRENT-ASSETS>                                80,443
<PP&E>                                         102,027
<DEPRECIATION>                                (49,893)
<TOTAL-ASSETS>                                 164,326
<CURRENT-LIABILITIES>                           67,183
<BONDS>                                         33,000
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           181
<OTHER-SE>                                      56,384
<TOTAL-LIABILITY-AND-EQUITY>                   164,326
<SALES>                                              0
<TOTAL-REVENUES>                               208,517
<CGS>                                                0
<TOTAL-COSTS>                                  169,749
<OTHER-EXPENSES>                                 9,995
<LOSS-PROVISION>                                   189
<INTEREST-EXPENSE>                               1,816
<INCOME-PRETAX>                                 27,674
<INCOME-TAX>                                    10,793
<INCOME-CONTINUING>                             16,881
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    16,881
<EPS-PRIMARY>                                      .88
<EPS-DILUTED>                                      .88
        

</TABLE>
