He called 265 to win ~1000 + ~600 more at the river, assuming he read you had the straight and would pay him off at the river no matter what if the board paired or not. With 10 outs (1xT,3xJ,3xQ,3xA) that is marginally +EV.

Btw, the turn play could as well be another straight (reraising AI would only make sense with Kdxd), so I guess your river call is ok.