While fans of “The Book of Mormon” will crack up at the jokes in this blockbuster Broadway musical about Utah missionaries trying to convert Ugandans, Minneapolis civic leaders have other reasons to smile.

“Mormon,” which opens Tuesday for a three-week run at the Orpheum — its third engagement there in four years — will draw roughly 20,000 patrons a week to downtown Minneapolis. And that’s just some of the half a million people who annually see touring Broadway shows, concerts and comedy performances at the big playhouses on Hennepin Avenue.

These patrons, many from the suburbs, spend at restaurants, stay in hotels and pay for parking, creating a multiplier economic impact of $2.70 for every dollar spent, according to theater officials.

But they bring more than dollars to a strip once left desolate after the demographic changes of the 1970s and 1980s, when white middle-class families migrated to the suburbs. They add vitality to Minneapolis’ marquee entertainment district, and underscore how the arts can serve as engines of civic growth.

“Blockbusters are great door openers, not just for theater and the artists, but also for the city and downtown,” said Jim Sheeley, president of the Upper Midwest region of Broadway Across America, which works to present shows on Hennepin. “I can’t tell you how many theaters were renovated across the country to accommodate ‘Phantom of the Opera.’ ”

Sheeley has been observing the scene since the 1970s, when the weeks of touring Broadway programming in the Twin Cities could be counted on one hand. Today, the Hennepin Theatre Trust, which presents shows at the Orpheum, State and Pantages theaters in Minneapolis as well as St. Paul’s Ordway Center, averages 22 weeks of Broadway programming a year. That growth is directly tied to blockbuster musicals such as “Phantom,” “The Lion King,” “Les Misérables” and “Mamma Mia!”

“Big shows develop new audiences and create really vital economic spin,” said Jamie Grant, the Ordway’s new president. “People often buy tickets way in advance, which means that by the time the show rolls around, they’ve paid off their credit card bills and can spend more.”

Stage juggernauts are rare in the theater business, of course; 75 percent of commercial shows do not recoup their initial investments. The ones that do succeed serve manifold masters.

Patrons flock to them for escapist pleasure and the sheer thrill of seeing something that blows them away.

And artists love them for personal reasons involving stardom and stable earnings in an industry renowned for its fickle employment prospects.

“I was able to buy an apartment in Manhattan and take care of people close to me,” said “Mormon” director and choreographer Casey Nicholaw, whose four current Broadway shows (“Tuck Everlasting,” “Aladdin,” “Something Rotten!” and “Mormon”) tie the record for a single director.

We’re a magnet for shows

As a theater mecca, the Twin Cities area is a magnet for touring blockbusters, including “The Lion King,” which had its world premiere at the Orpheum in 1997 and has since become the biggest Broadway blockbuster of all time, taking in more than $6 billion internationally.

Steve Cramer, a former Minneapolis City Council member who now heads the Downtown Council, said that blockbusters “are part of a unique experience that you can only have in downtown Minneapolis or St. Paul. You can go to a game at a stadium, go to a concert at Target Center and go see a Broadway show. The blockbuster is the heart of that experience.”

In the old days, New York producers packaged shows — some of them subpar — and shipped them out, expecting people in “the sticks” not to know the difference.

That began to change in the 1980s, when uber-producer Cameron Mackintosh insisted that touring shows not water down the production values of hits such as “Cats,” “Les Miz” and “Miss Saigon.” Some of these shows had huge spectacles, such as a helicopter landing in “Saigon.”

Now the problem, sometimes, is managing audience expectations, said Sheeley, who over a four-decade career has hosted many a Mackintosh production. “People sometimes expect the moon.”

In the 1980s and ’90s, patrons decried the blockbuster trend as spectacle-heavy. But detractors are mostly quiet today — partly because no one is landing helicopters onstage anymore.

Blockbuster veterans

For several Twin Cities artists, these shows were godsends.

Kerry Casserly was in the original production of “A Chorus Line,” an association that continues to pay off 40 years later. She toured Europe and the U.S. with the show and, as a director and choreographer, has become part of the brain trust to preserve the vision of its creator, Michael Bennett. She recently codirected a revival at the Ordway.

“I’ve done other things, of course, but it’s my closest showbiz family and will always be,” she said.

Actor Michael Gruber was in “A Chorus Line” when it became Broadway’s longest running show ever. A few years later, he was in “Cats” when it broke that record. “To be in one of those is neat and thrilling,” he said. “But in this business, you’re only as good as your latest performance.”

Linda Talcott Lee, a dancer and choreographer who teaches at the University of Minnesota, said that the upside of being in a long-running blockbuster was that she was able to plan her family. Lee was in “Beauty and the Beast” for nine years — more than 3,000 performances. She was pregnant with both of her children in the show — “I danced until I was five months each time,” she said. “Many women in this business lose the opportunity to have children because of the demands of the business.”

And the downside of being in a blockbuster? Things can become stale.

“You don’t ever want to phone it in or have it just become a paycheck,” Lee said. “If an actor stays in a show for a long time, agents think that you’ve lost your edge or couldn’t get another job. But all in all, there’s nothing like being in a Broadway blockbuster.”