Others have given you the answer, I will say essentially the same thing, but lay it out in a different way.
I didn't look it up, but someone said your speakers were 86db Sensitivity rating. That means you can reach reference levels with less than 1 watt. But to reach Peak levels of 105db, take considerably more power. This is how it works out, for every 3db increase in volume, the power Doubles.
86db = 1 watt
89db = 2 w
92db = 4w
95db = 8w
98db = 16w
101db = 32w
104db = 64w (close enough)
But this is at 1 meter. Mathematically, every time the distance doubles, the sound falls by 6db. However, many claim that in a normal room, it actually falls by only 3db.
If we move from 1 meter to 2 meters the sound falls by 6db, if we move from 2 meters to 4 meters if falls by 6db again, for a total of 12db. 4 meters = 13.12 feet.
So, we need to subtract 12db from the 104db = 64w
104db -12db = 64w
92db = 64w
95db = 128w
98db = 256w
101db = 512w
104db = 1024w
Though again, likely in-room the sound only drops by -3db every time the distance doubles.
104db -6db = 64w
98db = 64w
101db = 128w
104db = 256w
Bearing in mind, that average levels are much much less than that. At relatively loud volumes you are probably averaging in the 2w to 4 watt range.
Most AV Receiver, vaguely in the area of 100w/ch, have no problem reaching Reference Levels in a typical room. Given that you are looking at Anthem amps, I don't see you having any trouble at all.
The Amthem A5 is rated at 220w/ch to 8 ohms, and 180w/ch with all channels driven. That is an indicator of a very strong power supply backing up the amps.
The Anthem P5 are a massive 325w/ch to 8 ohms with all channels driven. Both a very strong amp with a very strong power supply. If you are using 4 ohm speaker with the amps, then you definitely want amps with strong power supplies.
So, it is really down to your budget.
Echoing what FMW has said, the size of the room is very important. How many seats? How far from the Screen? Tiered Seating? Room Dimensions? Etc....? It take more power to fill a large room.
All that said, with a basic 120w/ch Stereo amp, I had no problem reaching 95db average with 110db peaks during The Hobbit on BluRay. That is massively loud and very substantially above Reference Levels.
Generally, most amps can reach the necessary levels in a common sized room. But, to know more about the power you would need in your room, we would need to know a lot more about the room itself.
That said, I can't imagine either of the suggested amps falling short of filling your needs.
Steve/bluewizard