pthread_detach doesn't release memory

[Peter Steele]

I create a thread using something like this: 

pthread_t thread; 
pthread_create(&thread, NULL, mythread, NULL); 
pthread_detach(thread); 

I use the detach because I want to make sure the thread's resource are reclaimed when the thread completes. However, this does not seem to work. Each time I create a thread the application's memory footprint grows by 128 bytes and this memory is never released. 

Am I doing this right?