KK with a sea of callers

[tdarko]

3/6 NL

stacks:
UTG- 346
Hero- 955
SB- 720

dealt black kings on the button. 6 limpers in front of me i raise it to $60, both blinds call, and 3 limpers call. (this is weird to me [img]/images/graemlins/confused.gif[/img])

flop (A [img]/images/graemlins/diamond.gif[/img] 6 [img]/images/graemlins/diamond.gif[/img] 7 [img]/images/graemlins/club.gif[/img])~318
checked to me, Hero checks

turn (A [img]/images/graemlins/diamond.gif[/img] 6 [img]/images/graemlins/diamond.gif[/img] 7 [img]/images/graemlins/club.gif[/img] 2 [img]/images/graemlins/heart.gif[/img])~318
checked to me, Hero checks

river (A [img]/images/graemlins/diamond.gif[/img] 6 [img]/images/graemlins/diamond.gif[/img] 7 [img]/images/graemlins/club.gif[/img] 2 [img]/images/graemlins/heart.gif[/img] K [img]/images/graemlins/heart.gif[/img])~318
SB&BB check, UTG goes all in $296, folded to me Hero calls, SB calls, BB folds.

thoughts on the overcall here and other streets? i had two others to act and didn't want to shove a possible caller out of the pot. flop and turn play, too passive even though i am certain to be behind here?