Russ Feingold got a lot a of grief on the Left when he supported John Roberts' nomination as Chief Justice but I think he understood Roberts's better than most so-called conservative did.
Roberts may be a conservative but he's not an ideological one. Ergo his decisions are going to be made with best interest of the status quo and of the national government (which, coincidentally is the best interests of the business community). And as confirmed Republican, he's going to keep an eye as to what's best for the party (which why his court will never overturn Roe vs. Wade).
"Textualism" or "strict constructionalism" is an ideology and one I'm sure Roberts probably laughs at. If by textualism one means most what is permitted by law in the country is un-Constitutional because it wasn't put down on paper back in 1787, then I would say then most of what the Federal Government permits by law is certainly unconstitutional. But since the law is made and interpreted in the reality of 2015, embracing such a narrow vision of the law is not something Roberts' is going to share. One could make the argument the Court has gone beyond its "textual" mandate since Chief Justice John Marshall ruled on Marbury v. Madison. Indeed, Roger Taney's "textualism" on slavery basically help to cause the War Between the States.
Instead, Roberts did exactly what the business community wanted in keeping Obamacare instead of creating chaos in the healthcare markets by overturning it. The ideologue may have wanted Obamacare gone, but Roberts the actual conservatives knew this would be folly, especially over a stupid wording mistake and voted once again (!) to uphold it.