Question:  Argent Corporation was a company in Las Vegas that at one time controlled a hotel that operated when?
Context: The Tropicana – Las Vegas Boulevard intersection on the Las Vegas Strip (Tropicana Avenue and Las Vegas Boulevard), is noteworthy for several reasons.  It was the first intersection in Las Vegas completely closed to street level pedestrian traffic and its four corners are home to four major resorts: Excalibur Hotel and Casino, Tropicana Las Vegas, New York-New York Hotel and Casino and MGM Grand Las Vegas—the latter has 5,044 rooms and was once the largest hotel in the world.  The resorts at the four corners have a total of 12,536 hotel rooms as of 2016. Downtown Las Vegas (commonly abbreviated as DTLV) is the central business district and historic center of Las Vegas, Nevada.  It is the original townsite and was the gambling district of Las Vegas prior to the Strip, and the area still incorporates downtown gaming.  As the urban core of the Las Vegas Valley, it features a variety of hotel and business highrises, cultural centers, historical buildings and government institutions, as well as residential and retail developments.  Downtown is located in the center of the Las Vegas Valley and just north of the Las Vegas Strip, centered on Fremont Street, the Fremont Street Experience and Fremont East.  The city defines the area as bounded by I-15 on the west, Washington Avenue on the north, Maryland Parkway on the east and Sahara Avenue on the south. Air Vegas (IATA: 6V, ICAO: VGA, Call sign: Air Vegas) was an airline with its headquarters on the grounds of the North Las Vegas Air Terminal in North Las Vegas, Nevada.  It operated daily sightseeing flights from Las Vegas to the Grand Canyon.  Prior to moving to the North Las Vegas Airport its main bases were McCarran International Airport (LAS), Las Vegas and Henderson Executive Airport (HND), Las Vegas. Argent Corporation was a company in Las Vegas that at one time controlled the Hacienda Hotel/Casino, the Stardust Resort & Casino, the Fremont Hotel and Casino and the casino in the Marina Hotel.  The company was owned by Allen Glick, a San Diego real estate investor.  The name Argent came from the three initials of his name, combined with the first three letters of the word "Enterprises".  However, state and local officials in Nevada believed that the casinos were controlled by organized crime families in the Mid-West and that a huge skimming operation was conducted within the casinos. The Westgate Las Vegas Resort & Casino is a hotel and casino in Winchester, Nevada.  It is owned by Westgate Resorts and operated by Navegante Group.  It has 2,956 hotel rooms including 305 suites.  It opened in 1969 as the International Hotel, and was known for many years as the Las Vegas Hilton, then briefly as the LVH – Las Vegas Hotel and Casino.  It was renamed the Westgate Las Vegas on July 1, 2014. The Las Vegas metropolitan area is home to many sports, most of which take place in the unincorporated communities around Las Vegas rather than in the city itself.  The Las Vegas Valley has one major league professional team: the Vegas Golden Knights of the National Hockey League (NHL) who began play in 2017 as the region's first major pro team.  The Oakland Raiders of the National Football League (NFL) will begin play in Las Vegas as the "Las Vegas Raiders" by 2020 and become the region's second major professional team.  Las Vegas is also home to one minor league sports team: the Las Vegas 51s of the Triple-A Pacific Coast League (Minor League Baseball).  The 51s are currently the only team to actually play in the city of Las Vegas, playing at the city owned Cashman Field.  They will be joined in 2018 by the Las Vegas Lights FC of the United Soccer League, one of two leagues that collectively make up the second level of the U.S. men's soccer league system. The Trump International Hotel Las Vegas is a 64-story luxury hotel, condominium, and timeshare located on Fashion Show Drive near Las Vegas Boulevard, just off the Las Vegas Strip in Paradise, Nevada, named for real estate developer and the 45th and current President of the United States Donald Trump.  It is located across the street from Wynn Las Vegas, behind Alon Las Vegas on 3.46 acre , near the Fashion Show Mall, and features both non-residential hotel condominiums and residential condominiums.  The exterior glass is infused with gold.  The hotel is a member of The Leading Hotels of the World. El Rancho Vegas was a hotel and casino on the Las Vegas Strip.  It was located at 2500 Las Vegas Boulevard, at the southwest corner of Las Vegas Boulevard and Sahara Avenue, and opened on April 3, 1941.  Until 1942, it was the largest hotel in Las Vegas with 110 rooms.  On June 17, 1960, the hotel was destroyed by fire.  In 1982, the El Rancho Hotel and Casino formerly known as the Thunderbird and later as the Silverbird opened across the street from the former site of the El Rancho Vegas, creating some confusion. The Palazzo is a luxury hotel and casino resort located on the Las Vegas Strip in Paradise, Nevada.  It is the tallest completed building in Nevada.  Designed by the Dallas based HKS, Inc., the hotel offers luxury in an Italian Renaissance ambiance.  The hotel and casino are part of a larger complex (operated as one hotel) comprising the adjoining Venetian Resort and Casino and the Sands Convention Center, all of which are owned and operated by the Las Vegas Sands Corporation. The Hacienda Resort Hotel and Casino was a hotel and casino on the Las Vegas Strip in Paradise, Nevada, that operated from 1956 to 1996.  It was one of a chain of four Hacienda properties, with the other three being located in Fresno, Bakersfield, and Indio, California.  Each Hacienda featured a distinctive horse and rider sign; the Las Vegas sign is now prominently displayed at the Neon Museum.
Answer: from 1956 to 1996