ATs in small blind

[afk]

I'm relatively new to the table and new to shorthand. MP3 seems rather maniacal, CO is a bad calling station. Is this river a ridiculously easy call in this spot (especially considering pot size)? I'm still working out the kinks in playing with maniacs at this game.

PokerStars 0.50/1.00 Hold'em (6 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

Preflop: Hero is SB with A/images/graemlins/club.gif, T/images/graemlins/club.gif.
<font color="#666666">1 fold</font>, MP calls, CO calls, Button calls, <font color="#CC3333">Hero raises</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">MP 3-bets</font>, CO calls, Button calls, Hero calls.

Flop: (13 SB) T/images/graemlins/spade.gif, 5/images/graemlins/club.gif, Q/images/graemlins/spade.gif <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">MP raises</font>, CO calls, Button calls, Hero calls.

Turn: (10.50 BB) 6/images/graemlins/diamond.gif <font color="#0000FF">(4 players)</font>
Hero checks, <font color="#CC3333">MP bets</font>, CO calls, Button calls, Hero calls.

River: (14.50 BB) 3/images/graemlins/club.gif <font color="#0000FF">(4 players)</font>
Hero checks, <font color="#CC3333">MP bets</font>, CO folds, Button calls, Hero folds.

Final Pot: 16.50 BB