Revenue Recognition Rental revenue is recognized when earned from residents of the Company's multifamily communities, which is over the terms of rental agreements, typically of 13 months  duration. Differences from the straight-line method, which recognize the effect of any up-front concessions and other adjustments ratably over the lease term, are not material. The Company evaluates the collectability of amounts due from residents and maintains an allowance for doubtful accounts for estimated losses resulting from the inability of residents to make required payments then due under lease agreements. The balance of amounts due from residents are generally deemed uncollectible 30 days beyond the due date, at which point they are fully reserved. Rental revenue from tenants' operating leases in the Company's retail shopping centers is recognized on a straight-line basis over the term of the lease regardless of when payments are due. Revenue based on "percentage rent" provisions that provide for additional rents that become due upon achievement of specified sales revenue targets (as specified in each lease agreement) is recognized only after the tenant exceeds its specified sales revenue target. Revenue from reimbursements of the tenants' share of real estate taxes, insurance and common area maintenance, or CAM, costs are recognized in the period in which the related expenses are incurred. Lease termination revenues are recognized ratably over the revised remaining lease term after giving effect to the termination notice or when tenant vacates and the Company has no further obligations under the lease. Rents and tenant reimbursements collected in advance are recorded as prepaid rent within other liabilities in the accompanying consolidated balance sheets. The Company estimates the collectability of the tenant receivable related to rental and reimbursement billings due from tenants and straight-line rent receivables, which represent the cumulative amount of future adjustments necessary to present rental revenue on a st