Detroit automakers have come full circle, relying as they did before the financial crisis on profits from selling trucks and sport utility vehicles in the United States to cover losses overseas. Ford Motor Co’s (F.N) first-quarter results on Tuesday highlight how reliant the Detroit Three have become once again on their biggest, least- fuel-efficient models. Higher costs for materials, manufacturing and engineering dented the results, but Ford’s North American take was more than enough to offset the $404 million in pre-tax losses from other regions.