Using nlapiGetCurrentLineItemText with a Transaction Column Field

I'm new to Suite Script and think I have a simple question about using nlapiGetCurrentLineItemText to do some basic expense line validation.  

I have created two transaction column fields (type: List/Record) with ID's of  custcol_hotel_detail and custcol_airline_detail

Here is the initial code I have written: 

function validate_detail()
{
  // check to see whether airline detail and hotel detail are provided.

  var category = nlapiGetCurrentLineItemValue ('expense', 'expcategory');
  var hotel = nlapiGetCurrentLineItemText('expense','custcol_hotel_detail');
  var airline = nlapiGetCurrentLineItemText ('expense', 'custcol_airline_detail');

  alert ("Category is: " + category + "Hotel Detail is: " + hotel + " airline detail is: " + airline);

  return true;

}

When I attempt the add the expense line, I get the alert that correctly shows the Value of the category.  However, the variables for the transaction column fields (hotel and airline) show a null value despite the fact that I have selected one of the list values.    My intention is to have the function show the text of the item in the list selected.    Once I know it is working the way I intend, I would move forward with the additional code.