B737-500 CREW HAD A TRACK DEV WHILE ON THE AACES RNAV 1 DEP AT LAS.

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DEV OFF COURSE. WE DEPARTED LAS FOR ZZZ. DEP WAS OFF RWY 25R ON THE AACES RNAV 1 DEP. THE FO WAS FLYING THE DEP WITH LNAV AND AUTOPLT SELECTED AS PER COMPANY FOM PROCS. APCHING LODZY FIX; THE CTLR CLRED US DIRECT TO IDALE FIX AND RESUME THE AACES DEP. I ACKNOWLEDGED THE CALL AND ENTERED IDALE INTO THE 'DIR INTC' PROMPT BOXES ON THE FMC AND THEN EXECUTED THE CHANGE. I MADE THIS CHANGE QUICKLY WITHOUT CONFIRMING WHAT I HAD SELECTED. THE FO DID NOT CHK THE CHANGE EITHER. THE ACFT MADE A R TURN (AS EXPECTED) AND ROLLED OUT APPROX 170 DEG HDG AND PASSING 6000 FT MSL. THE CTLR ASKED WHERE WE WERE GOING AND I REPLIED 'DIRECT IDALE ON THE AACES DEP. HE SAID WE HAD TURNED TOO FAR; THAT IDALE WAS TO OUR R. HE THEN TOLD US TO CONTINUE ON OUR HDG; DIRECT HITME (THE FIX AFTER IDALE ON THE DEP). I THEN REALIZED THAT I HAD INADVERTENTLY SELECTED HITME ON THE FMC INSTEAD OF IDALE AND THAT WE HAD DEVIATED OFF COURSE. THE CTLR STOPPED OUR CLB AND SWITCHED US TO THE NEXT FREQ WHERE WE WERE GIVEN A VECTOR FOR SPACING AND TOLD TO CALL LAS DEP UPON ARR IN ZZZ. CALLED LAS DEP FROM ZZZ AND THE CTLR SAID THERE WAS NO PROB; THEY JUST WANTED TO KNOW WHAT HAPPENED. I TOLD THEM IT WAS OPERATOR ERROR. IN RETROSPECT; IF I HAD FOLLOWED FOM PROCS AND CONFIRMED THE CHANGE WITH THE OTHER CREW MEMBER; WE WOULD HAVE CAUGHT THE ERROR BEFORE EXECUTING THE FMC.