
<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM CONSOLIDATED
BALANCE SHEETS AND CONSOLIDATED STATEMENTS OF INCOME AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               JUN-30-1998
<CASH>                                          40,914
<SECURITIES>                                         0
<RECEIVABLES>                                   28,821
<ALLOWANCES>                                   (1,200)
<INVENTORY>                                          0
<CURRENT-ASSETS>                               103,137
<PP&E>                                         107,376
<DEPRECIATION>                                (53,662)
<TOTAL-ASSETS>                                 192,294
<CURRENT-LIABILITIES>                          103,666
<BONDS>                                         31,000
<PREFERRED-MANDATORY>                              178
<PREFERRED>                                          0
<COMMON>                                             0
<OTHER-SE>                                      47,901
<TOTAL-LIABILITY-AND-EQUITY>                   192,294
<SALES>                                              0
<TOTAL-REVENUES>                               167,370
<CGS>                                                0
<TOTAL-COSTS>                                  133,254
<OTHER-EXPENSES>                                 6,484
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               1,328
<INCOME-PRETAX>                                 28,167
<INCOME-TAX>                                    10,985
<INCOME-CONTINUING>                             17,182
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    17,182
<EPS-PRIMARY>                                      .97
<EPS-DILUTED>                                      .90
        

</TABLE>
