"strict idea" is correct and usable in written English.
You can use it to describe a fixed concept or belief -- for example, "She refused to consider any other options, so she held fast to her strict idea of what was right."
Those of us of a certain age were brought up with a very strict idea of timekeeping, and were led to believe that it reflects well on a person's character.
Crucial is an implicit, and very strict, idea of sustainability, which in effect denies that natural resources can often be replaced or augmented by man-made ones.This aside, the main drawback of the analysis is the way it treats energy.
Updike's widow, Martha, who helped her husband put the finishing touches on the collection, said he had a strict idea of who should see it: "legitimate, bona fide academics".
A family is more about what love you give to a child than this strict idea".
"In our culture we have strict ideas about what makes a good holiday.
The solid point is that women's sexuality is still bound up in strict ideas about evolution.
For people with very strict ideas about gender, obviously, the idea of two men falling in love goes against traditionally limited roles.
Richly coloured rugs, chair covers, and cushions contrasted with dark furniture, which was arranged according to the strict ideas of asymmetrical balance.
Oddly, Montaigne learned to speak Latin before he learned to speak anything else, thanks to his father's strict ideas about schooling.
Every "um" and "ah" and extraneous "like" is given considered rhythmic emphasis, as if these chatty ramblings were composed with strict ideas of meter in mind.
These 3-millimeter-long insects aren't comparison shoppers, new research using ants tagged with tiny radio transmitters shows, but rather have some strict ideas of what they are looking for.
