Whenever possible, the parties' intent must be ascertained from the policy language alone. In construing a policy, a court should give words their plain meaning according to common usage, and avoid strained constructions. Unless there is an ambiguity in the terms of a policy, a court should avoid strained interpretations and should enforce an insurance contract as written. A provision is ambiguous when it is reasonably susceptible to more than one meaning. Farm Mutual Automobile Insurance Co ., supra .
Any ambiguities are to be construed against the drafter and in favor of the insured.
The interpretation of an insurance contract is a question of law that we review de novo . The limit of liability shall be reduced by all sums paid because of bodily injury or property damage by or on behalf of persons or organizations who may be legally responsible. . . . . If there is other applicable similar insurance we will pay only our share of the loss. Our share is the proportion that our limit of liability bears to the total of all applicable limits. However, any insurance we provide with respect to a vehicle you do not own shall be excess over any other collectible insurance.