Earthwise Energy appeals the district court’s grant of summary judgment for Crusader Energy Group in this title dispute over oil and gas leases in north Texas. Earthwise Energy contends the court erred in concluding that the assignment from Gulftex Operating, Inc. to Earthwise of certain interests in oil and gas leases did not include the disputed interests Gulf-tex had formerly conveyed to Crusader Energy Group.

Our review of a grant of summary judgment is de novo. Greenwood 950, L.L.C. v. Chesapeake Louisiana, L.P., 683 F.3d 666, 668 (5th Cir. 2012). We also conduct de *298 novo review of the district court’s interpretation of a contract and its determination of whether a contract is ambiguous. Id. The parties are familiar with the facts of this case. We have considered the district court’s decision, the briefing, and the oral arguments. For the reasons expressed by the district court in its thorough and well-reasoned opinion, we AFFIRM.