Thoughts in italics?

I'm just tossing this out there to see if there's any consensus.

How do you render thought in the POV character's narration? That is:

Hailey gazed at the swirls and jolts of red that made up the painting and said, "Very, uh, modern. And impressive." (She thought, My kindergartener could have done that with fingerpaint.) But she couldn't say that out loud, not with Jim beaming so proudly.

Now that part in parentheses (I put in the parentheses) -- that's her thought. So would you put it in italics? Would you have a "thought tag" like "she thought" or "she mused"? Would you do italics if you had a quote tag?
Alicia