CBS has ordered eight more episodes of its Sherlock Holmes drama Elementary, whose sixth season is going up from 13 to 21 episodes. There is no premiere date or time slot for the series yet, but given its full-season order, it may debut soon.

Elementary most recently aired on Sunday for a season and a half, and its back order comes on the heels of CBS opting not to order additional episodes of its new Sunday drama series Wisdom of the Crowd, creating an imminent opening on the night, the only one for a drama series on the network’s schedule at the moment. It would make sense for Elementary, a modest but reliable performer, to rejoin the night, possibly at 10 PM, with NCIS: Los Angeles and Madam Secretary sliding back to 8 PM and 9 PM where they had done well.

Elementary surprisingly did not make the list of early CBS renewals for the first time this year, spending its first spring on the bubble. There never was serious doubt for the crime drama, fully owned by CBS. Indeed, it was renewed in May, though for the first time it did not land on the fall schedule, getting a 13-episode midseason order. It will now produce 21 episodes, just shy of the 24 it aired in each of its first five seasons.

While its linear ratings in the Sunday 10 PM hour have been so-so (7.4 million viewers, 1.2 in 18-49 Live+7 last season), Elementary has off-network and SVOD deals with WGN America, Hulu Plus and broadcast stations that fetch in as much as $3 million total per episode. It is a solid international seller for CBS TV Studios too, in part because of the central character’s global recognition. In May 2016, CBS Corp. CEO Les Moonves used Elementary as an example of a program ownership success story, telling investors that the show had “made approximately an $80 million profit for the corporation” the previous year.

Elementary stars Jonny Lee Miller, Lucy Liu, Aiden Quinn, Jon Michael Hill and Desmond Harrington. Robert Doherty, who developed the series, executive produces with Carl Beverly, Sarah Timberman, Jason Tracey, Robert Hewitt Wolfe and Bob Goodman for CBS TV Studios.