Generating random priorities for a treap in C++

I am creating a treap, and I want to know, which random number generator is most suitable for generating priorities at insertion.

The data set is about 6000 items long.

I am modifying an existing template class(largely just declared methods without definitions) that was given to us. The predefined generator is std::default_random_engine which only generates pseudo-random numbers. I would like to know, if this generator is sufficient, and if not, what are the alternatives? The data will be read from a file all at once.

The random number generator is declared as:

std::default_random_engine* generator_;

It's only used when creating in a constructor of a wrapper class

TreapItem<K, T>(key, data, (*generator_)())

I'd like to have the least number of collisions possible. Is std::default_random_engine* generator_; enough, to achieve no collisions, or is there a need for some other generator?