Mapping one to zero with entity framework

Good afternoon, I have a document table that has relationship 1 to 0 with another table of Usuario to return the user name, but I get the error:

  

Conversion specified is not valid.

My mapping:

public class DocumentoOffConfiguration : EntityTypeConfiguration<DocumentoOff>
{
    public DocumentoOffConfiguration()
    {
        ToTable("DOCUMENTO");

        this.Property(x => x.DataCriacao).HasColumnName("DATACRIACAO");
        this.Property(x => x.Enviadoar).HasColumnName("STATUS");
        this.Property(x => x.UsuarioId).HasColumnName("USUARIO_ID");

    }
}

In View try to show the following field:

<th>
@(Html.SortingColumn("Fiscal", nameof(Model.Usuario.Nome), 
    "Index", new { Model.Usuario.Nome }, 
        new AjaxOptions { UpdateTargetId = "div-gerenciador-auto-termos-index", 
        HttpMethod = "POST" 
    }))
</th>

public UsuarioOffConfiguration()
{
    this.ToTable("USUARIO");

    this.Property(x => x.UsuarioId)
        .HasColumnName("ID");

    HasMany(x => x.Documentos)
        .WithRequired(x => x.Usuario)
        .HasForeignKey(x => x.UsuarioId);
}

But the above mentioned error has been returned to me, can anyone give me a light on how to solve it?