Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE Documents (document_id VARCHAR); CREATE TABLE Documents_with_expenses (document_id VARCHAR)
### Question:
What are the ids of documents which don't have expense budgets?
### Answer:
SELECT document_id FROM Documents EXCEPT SELECT document_id FROM Documents_with_expenses