Wording that is clearly parenthetical – an aside, explanation, or afterthought – should be treated as though non-restrictive and sandwiched with commas.
The train, as far as I saw, was not moving.
The number of the house, he thought he
remembered, was 2846.He usually arrived on time, give or take a few minutes.
Note in the final sentence that the parenthetical wording comes at the end of the sentence. This example might also have been discussed in the section on concluding phrases and clauses.
Worksheet punctuating parenthetical wording