Just wanted to share my code for future users (as it wasn't obvious to me how to implement color formatting when detail grid is opened)
detail model refresh function:
refresh: function( event, ui ) {
var id = $(this).data("rowData")["id"];
var data = ui.dataModel.data;
for (var i = 0; i < data.length; i++)
{
if(data["detailID"] == id)
{
row = $(this).pqGrid( "getRow", {rowIndx: i} );
row.addClass("grid-cell-highlight-valid-light");
}
}
},