Ideas vs Concepts
A concept can be taken psychologically or logically for what we grasp to understand as as expression or an idea. Afterall, a concept is the basic element of thought. But concepts are really much more in that they encompass larger areas and elements of a complete process.
They can then be taken as a complete understanding of a complex process or untertaking. The concept of Economics, for example must have both abstact and concrete elements to it to completely understand its total concept. A concept can also define a category or class of individuals.
Whereas an idea is usually more of a thought or thought process about something.