Hello and thanks for requesting me.
The seriousness of a theft offense in Michigan depends upon the value of what was taken. If the value is over $20,000, that would be a felony in Michigan. It would have a maximum possible penalty of ten years of imprisonment, and/or a fine of up to $15,000 or three times the value of the stolen, whichever is greater, so in this instance your fine could exceed $300K.
As for plea agreements, a defendant is never required to go to trial on a case. He can always get a plea agreement. The only issue is whether he's likely to want the plea agreement that he can get.
A prosecutor has the power to reduce or dismiss charges. He or she will look at the strength of his case, at the criminal history of the defendant, and the various facts and circumstances involved in the incident and make an offer based on what he thinks the case is worth. A judge can also make an offer, but a judge does not have the power to reduce or dismiss the charges.
Typically, on a first no-violent theft offense, prison can be avoided and the typical sentence is felony probation and restitution to the complainant. That is particularly true when the theft is not only a first offense but an isolated event. However, the amount involved is large, and so a non-incarceratory disposition may have to be negotiated for.