think piece

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A newspaper article consisting of news analysis, background material, and personal opinions.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An in-depth article that discusses a topic thoroughly and elaborates the writer's point of view, to inspire deep thought related to the article's subject. Think pieces are usually published in magazines, newspapers or web sites.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an article in a newspaper or magazine or journal that represents opinions and ideas and discussion rather than bare facts