Fluent NHibernate: How to create one-to-many bidirectional mapping?

public class Summary
{
   public int id {get; protected set;}

   public IList<Detail> Details {get; protected set;}
}

public  class Detail
{
   public int id {get; protected set;}

   public string ItemName {get; set;}

  /* public Summary Owner {get; protected set;} */ //I think this might be needed for bidirectional mapping?
}

public class SummaryMap : ClassMap<Summary>
{
    public SummaryMap()
    {
        Id(x => x.ID);

        HasMany<Detail>(x => x.Details);
    }
}

public class DetailMap : ClassMap<Detail>
{
    public DetailMap()
    {
        Id(x => x.ID);

        Map(x => x.ItemName).CanNotBeNull();
    }
}

public class Detail
{
    public int id { get; protected set; }
    public string ItemName { get; set; }

    // Renamed to use same column name as specified in the mapping of Summary.Details
    public Summary Summary {get; set;}
}

public class Summary
{
    public Summary()
    {
        Details = new List<Detail>();
    }

    public int id { get; protected set; }
    public IList<Detail> Details { get; protected set; }
}

public class DetailMap : ClassMap<Detail>
{
    public DetailMap()
    {
        Id(x => x.id)
            .GeneratedBy.Native();

        Map(x => x.ItemName)
            .CanNotBeNull();

        References<Summary>(x => x.Summary)
            // If you don't want to rename the property in Summary,
            // you can do this instead:
            // .TheColumnNameIs("Summary_id")
            .CanNotBeNull();
    }
}

public class SummaryMap : ClassMap<Summary>
{
    public SummaryMap()
    {
        Id(x => x.id)
            .GeneratedBy.Increment();

        HasMany<Detail>(x => x.Details)
            .IsInverse()
            .AsBag(); // Use bag instead of list to avoid index updating issues
    }
}