Double Down is the developer behind the popular DoubleDown Casino game on Facebook, which gives players the chance to play games such as slots, blackjack, video poker, and roulette.

Launched in April 2010, DoubleDown has 4.7 million monthly active users, up from 3.3 million in October, according to AppData.com. Like other free Facebook casino games, users compete for play chips and can invite and compete against friends in a wide range of games and contests, with Double Down monetizing the games via advertising and other methods.

The deal is a combination of cash - $250 million paid upfront - and an additional $85 million in retention payments, with the remainder paid out in cash over three years based on certain financial targets being hit.

"As technological innovations increasingly influence consumer behavior, social dynamics are quickly transforming entertainment and gaming experiences everywhere," IGT Chief Executive Officer Patti Hart said in a statement.

IGT is primarily known for making and manufacturing a wide range of slot machines, producing about half of the slot machines used in the US. Its popular slots include Wheel of Fortune, MegaBucks, and Star Wars.

IGT has been active on the online front as well, including establishing a division for its online operations and acquiring several other companies - WagerWorks in 2005 and Entraction Holding in 2011 - that develop software for online gambling operators that run casino and poker sites.

IGT is rumored to be a potential player in the US market if online gambling is made legal on either the national or state level, potentially leveraging its technology for offering online games along with its existing relationships with casinos throughout the country.