The last time the Decemberists were in the spotlight they opened for Bob Dylan, received a Grammy nomination for best rock song and debuted at No. 1 on the Billboard chart with the rollicking, Americana-infused 2011 album “The King Is Dead.”

But in the midst of mounting success, the beloved baroque-pop ensemble from Portland, Ore. — which will perform Tuesday at Northrop — announced midtour that it would be taking a multiyear hiatus. Aside from an outtakes EP and a double live album, the Decemberists have been dormant the past four years.

“It really feels as if nothing has changed,” frontman Colin Meloy said of his re-energized band last week. “After a few shows, it was just like getting back on a bike.”

The group’s leader remained rather industrious in the interim. The bookish Meloy began publishing a children’s fantasy trilogy titled “Wildwood.” The final installment was released last year.

Even then, Meloy never put his songwriting pen down.

“It was nice, because after working on the books for a while it felt like I was going back to a mode of writing that I practiced prior to the band, like when I still had a day job or when I was in school,” the 40-year-old native of Helena, Mont., explained. “Like when writing songs was just something I had done purely for enjoyment.”

That sense of freedom and born-again curiosity served the Decemberists well, as the band’s seventh full-length, January’s “What a Terrible World, What a Beautiful World,” is its most well-rounded and accessible in years. Despite its darkly ambivalent title, the album is at once convivial, bittersweet and playful. It’s a fun yet sophisticated release, one that displays Meloy’s strengths as a plain-spoken, occasionally dismal lyricist with infectious indie-rock sensibilities.

From the self-described “ode to oral sex” romp that is “Philomena” to the bouncy pop smarts of “The Wrong Year” to the desert-folk bombast of “Better Not Wake the Baby,” the Decemberists cooked up a bath of assertive folk-rockers, with some orchestral flourishes.

But the album’s title suggests a more complex back story, one that surfaces on “12/17/12.” The album’s poignant centerpiece, named after the date of the massacre at Sandy Hook Elementary, carries cultural and personal significance for Meloy.

“It was in there because it was a pretty apt summation of how I saw the world at the time,” the father of two explained. “When it came time to give the record a name, it still fit, for better or worse.”

Meloy has a penchant for weaving tight, compelling narratives into his songs. But he staunchly dismisses being labeled a storyteller, calling the term “a little hokey.” Despite the potential sociopolitical connotations, it’s not surprising cultural commentary wasn’t exactly Meloy’s intent with “What a Terrible World.” And that’s fine. We have enough of that anyway.

“[‘12/17/12’] was my way of preserving the moment, which in a way is my attempt at doing something,” Meloy said. “One thing I remember writing after that incident was, ‘If you’re feeling helpless, if you’re feeling enraged, if you’re feeling despairing, take stock in what you do have and bring your loved ones closer to you’ — that’s what I’m trying to say.”