“Roman J. Israel, Esquire” (*** out of four) was an imperfect but engrossing story about an idealistic lawyer (Denzel Washington) whose principles and ethics are tested to the breaking point when he goes to work for a large law firm (headed by Colin Farrell) and becomes embroiled in a murder case. Washington’s usual superb performance and effortless charisma help keep this legal drama on track even as the story wanders and never really shifts into high gear. Farrell is also terrific as his cunning and tough-minded boss and they play off each other well.