Trotskyism , being the continuation of Marxism-Leninism
You clearly have no idea what you're talking about. "Marxism-Leninism" was a term coined by Stalin to describe his "version" (that is, the correct one) of Lenin's ideas. Trotsky always referred to his beliefs (later to be called Trotskyism) as "Bolshevik Leninism". He never claimed to have anything to do with Marxism-Leninism.
So how is this idealism, in your opinion?
In a lot of ways, Trotskyism seems more interested in the idea of revolution. A perfect example of this is the theory of "Permanent Revolution", which in complete oppostion to Leninism, poses the development of socialism in one country impossible. This completely fails to recognize the fact that capitalist and imperialist production and exchange on a global level leads to uneven development throughout the capitalist world which in turn means that the potential for a revolution to occur at any one time will only exist within defined and non-global areas. That is, there is no conceivable circumstance where the entire world will have a revolution at the same time. Trotskyism posits that in these instances, where a country can have a revolution, they should sit back and wait for the rest to get ready before actually building socialism. This is totally opposed to the Marxist-Leninist concept of building socialism in one country. This theory (socialism in one country), is not a negation of internationalism, but rather the scientific recognition of the actuality of capitalism.
"The Communists disdain to conceal their views and aims. They openly declare that their ends can be attained only by the forcible overthrow of all existing social conditions. Let the ruling classes tremble at a Communistic revolution. The proletarians have nothing to lose but their chains. They have a world to win.
Workers of the World Unite!" -Karl Marx
"The dictatorship of the proletariat, i.e., the organization of the vanguard of the oppressed as the ruling class for the purpose of suppressing the oppressors, cannot result merely in an expansion of democracy. Simultaneously with an immense expansion of democracy, which for the first time becomes democracy for the poor, democracy for the people, and not democracy for the money-bags, the dictatorship of the proletariat imposes a series of restrictions on the freedom of the oppressors, the exploiters, the capitalists. " -Vladimir Lenin
"The People's democratic dictatorship needs the leadership of the working class. For it is only the working class that is most far-sighted, most selfless and most thoroughly revolutionary. The entire history of revolution proves that without the leadership of the working class revolution fails and that with the leadership of the working class revolution triumphs." -Mao Zedong