<TABLE> <S> <C>

<PAGE>

<ARTICLE> 5
<LEGEND>
RESTATED FDS INCLUDING COLUMNS FOR THE PRIOR THREE PERIODS ENDED (MARCH 31,
1997, JUNE 30, 1997, SEPTEMBER 30, 1997) AND PRIOR YEAR END (DECEMBER 31, 1996)
</LEGEND>
<MULTIPLIER> 1,000

<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS                   YEAR
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997             DEC-31-1996
<PERIOD-START>                             JAN-01-1997             JAN-01-1997             JAN-01-1997             JAN-01-1996
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997             DEC-31-1996
<CASH>                                           5,724                  10,245                  15,379                  16,815
<SECURITIES>                                         0                       0                       0                       0
<RECEIVABLES>                                   80,264                  79,429                  84,967                  73,292
<ALLOWANCES>                                       917                   1,018                   1,075                     868
<INVENTORY>                                     17,822                  18,329                  18,211                  18,192
<CURRENT-ASSETS>                               145,091                 154,184                 160,318                 149,559
<PP&E>                                         109,279                 111,030                 111,915                 107,944
<DEPRECIATION>                                  67,954                  69,474                  69,362                  65,918
<TOTAL-ASSETS>                                 199,667                 208,932                 215,407                 199,885
<CURRENT-LIABILITIES>                           63,115                  69,526                  65,425                  74,020
<BONDS>                                          9,000                   9,000                  17,000                       0
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                        33,549                  33,549                  33,549                  33,549
<OTHER-SE>                                      86,224                  89,162                  91,594                  85,070
<TOTAL-LIABILITY-AND-EQUITY>                   199,667                 208,932                 215,407                 199,885
<SALES>                                        109,581                 228,816                 343,478                 468,274
<TOTAL-REVENUES>                               109,581                 228,816                 343,478                 468,274
<CGS>                                           95,477                 197,240                 296,209                 403,800
<TOTAL-COSTS>                                   95,477                 197,240                 296,209                 403,800
<OTHER-EXPENSES>                                     0                       0                       0                       0
<LOSS-PROVISION>                                     0                       0                       0                       0
<INTEREST-EXPENSE>                                  72                     232                     428                   1,270
<INCOME-PRETAX>                                  3,445                   9,317                  14,625                  20,629
<INCOME-TAX>                                     1,344                   3,646                   5,756                   8,078
<INCOME-CONTINUING>                              2,101                   5,671                   8,869                  12,551
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                     2,101                   5,671                   8,869                  12,551
<EPS-PRIMARY>                                      .60                    1.62                    2.54                    3.60
<EPS-DILUTED>                                      .60                    1.60                    2.50                    3.56


</TABLE>