Is Realpolitik diplomacy strategy based on pragmatism or idealism?

Realpolitik (German: [ʁeˈaːlpoliˌtiːk]; from German real 'realistic, practical, actual', and Politik 'politics') is the approach of conducting diplomatic or political policies based primarily on considerations of given circumstances and factors, rather than strictly following explicit ideological notions or moral and ethical premises. In this respect, it shares aspects of its philosophical approach with those of realism and pragmatism. It is often simply referred to as pragmatism in politics, e.g. "pursuing pragmatic policies" or "realistic policies".

Pragmatism