WASHINGTON — The Transportation Department yesterday demanded documents related to Toyota’s massive recalls in the United States, to find out if the automaker acted swiftly enough.

Toyota, meanwhile, said it would temporarily idle production at plants in Texas and Kentucky over concerns the recalls could lead to big stockpiles of unsold vehicles.

The legal documents demand that Toyota tell the government when and how the company learned of the safety defects in millions of vehicles whose gas pedals were liable to stick.