Initial and final period must contains a date and not contains in other date

I have this model:

public class Documento
{
   public int Id {get;set;}
   public int CustomerId {get;set;}
   public int DocumentTypeId {get;set;}
   public DateTime Date {get;set;} //issuance of the document
   public DateTime NextDate {get;set;} //will be valid
}

The Date property means the date the document was generated and the NextDate property is the date on which the document needs to be regenerated

Data sample

Id  -  CustomerId  -  DocumentTypeId           Date       -      NextDate
1   -  1           -     1              -  12/12/2017     -     12/12/2018 - Generate in 2017, expiring in 2018
2   -  1           -     1              -  12/12/2018     -     12/12/2019 - Generate in 2018, this ok
3   -  1           -     1              -  10/01/2017     -     10/01/2018

I need to search documents that were not generated in 2018

My starting date is 01/01/2018 and final 01/01/2019

I tried this:

db.Documents.AsNoTracking().AsQueryable()
                       .Where(x =>
                            DbFunctions.TruncateTime(x.Date) >= model.Start &&
                            DbFunctions.TruncateTime(x.Date) <= model.End &&
                            DbFunctions.TruncateTime(x.NextDate) >= model.Start &&
                            DbFunctions.TruncateTime(x.NextDate) <= model.End).ToList();

[Edit]

When initial and final date is passed 01/01/2018 and 01/01/2019 the return corret is:

Id  -  CustomerId  -  DocumentTypeId           Date       -      NextDate
3   -  1           -     1              -  10/01/2017     -     10/01/2018

Document with (Id 1) was generate in 2017 and valid until 2018. But in 12/12/2018 was regenerated (Id 2)