I need an idiom, phrase, or word that describes someone/entity who acts carelessly based on success.
I am trying to write a paper on the US 2008 financial crisis.
Quick overview: Banks handed out mortgage loans, then sold those loans. These loans were sold repeatedly to investors. When the money was paid to the banks, it was sent along to those who bought it. This was practically risk-free and gave profit. The banks started giving mortgage loans to those who usually couldn't afford it and were considered 'high-risk' to sell more loans and earn more money. Later, the mortgages couldn't be paid and investors lost money.
My paper is trying to point out how the banks' careless handing-out of loans led to the crisis. I tried to think of something that described the moment when they weren't thinking of the consequences because they were too successful. For instance,
Because the banks were too adj, they were carelessly handing out loans.
I thought of maybe 'blinded by success'...
Blinded by success, the banks careless handed out loans.
I'm not looking for careless, but rather a word that could also describe the part that they were overly confident from their success.