This excerpt taken from the WTSLA 10-K filed Apr 29, 2005.
Our company recognizes rent expense for operating leases on a straight-line basis (including the effect of reduced or free rent and rent escalations) over the initial lease term. The difference between the cash paid to the
landlord and the amount recognized as rent expense on a straight-line basis is included in deferred rent. Cash reimbursements received from landlords for leasehold improvements and other cash payments received from landlords as lease incentives are recorded as deferred rent. Deferred rent related to landlord incentives is amortized using the straight-line method over the initial lease term as an offset to rent expense.