Hive query creates temp folders

Hello, i’m using insertion in table using this query:

from temp_cdr
insert into table data_cdr partition(dt)
select temp_cdr.*, cast(concat(substring(endtime, 7, 4), substring(endtime, 4, 2), substring(endtime, 1, 2)) as int) as dt;

Query works fine creating missing partitions and also creating folder .hive-staging_hive_2015-09-21_17-16-57_118_6915829821044291073-1 in table directory. It seems like some sort of temp folder.

Since I’m going to use such insertions a lot, there would be many of those temp dirs. Why hive creating it without deletion. Is it realy temp dir? Can I remove it without consequences.