Hotel receivables consist mainly of receivables due from hotel guests and meeting and banquet room rentals. The Company typically does not require collateral as ongoing credit evaluations are performed. An allowance for doubtful accounts is established against any receivable that is estimated to be uncollectible.
Deferred Financing Costs
Deferred financing costs are the costs incurred to obtain long-term financing. The deferred financing costs are recorded at cost and are amortized using the straight-line method, which approximates the effective interest method, over the respective term of the financing agreement and are included as a component of interest expense in the consolidated statements of operations and comprehensive income. The Company expenses unamortized deferred financing costs when the associated financing agreement is refinanced or repaid before the maturity date, unless certain criteria are met that would allow for the carryover of such costs to the refinanced agreement. The Company presents the deferred financing costs for its Term Loans (as defined in Note 9) and mortgage loans on the balance sheet as a direct deduction from the carrying amount of the respective debt liability, which is included in debt, net in the accompanying consolidated balance sheets. The Company presents the deferred financing costs for its unsecured revolving credit facility (the "Revolver") on the balance sheet as an asset, which is included in prepaid expense and other assets in the accompanying consolidated balance sheets.
For the years ended December 31, 2018, 2017 and 2016, approximately $3.5 million, $3.5 million and $4.0 million, respectively, of amortization expense was recorded as a component of interest expense in the consolidated statements of operations and comprehensive income.
The Company expenses advertising costs as incurred. Advertising expense was approximately $9.1 million, $6.2 million and $4.2 million for the years ended December 31, 2018, 2017 and 2016, respectively, and is included in other operating expense in the consolidated statements of operations and comprehensive income.
The Company incurs costs during the review of potential hotel property acquisitions and dispositions, including legal fees and other professional service fees. In addition, if the Company completes a hotel property acquisition, the Company may incur transfer taxes and integration costs, including professional fees and employee-related costs. If the Company completes a hotel property acquisition that is considered to be an asset acquisition, the transaction costs are capitalized on the consolidated balance sheets. If the Company completes a hotel property acquisition that is considered to be a business combination, the transaction costs are expensed as incurred in the consolidated statements of operations and comprehensive income.
Derivative Financial Instruments
In the normal course of business, the Company is exposed to the effects of interest rate changes. The Company utilizes a variety of borrowing vehicles, including the Revolver and medium and long-term financings. The Company reduces its risk to interest rate changes by following its established risk management policies and procedures, including the use of derivative financial instruments as part of its interest rate risk management strategy. The Company utilizes derivatives to manage, or hedge, interest rate risk. To mitigate the Company's exposure to interest rate changes, the Company uses interest rate derivative instruments, typically interest rate swaps, to convert a portion of its variable rate debt to fixed rate debt. The Company attempts to require the hedging derivative instruments to be effective in reducing the interest rate risk exposure that they are designated to hedge. This effectiveness is essential in order to qualify for hedge accounting. Derivative instruments that meet the hedging criteria are formally designated as cash flow hedges at the inception of the derivative contract. The Company does not use derivative instruments for trading or speculative purposes.
Interest rate swap agreements contain a credit risk that the counterparties may be unable to fulfill the terms of the agreement. The Company has minimized the credit risk by evaluating the creditworthiness of its counterparties, who are limited to major banks and financial institutions, and it does not anticipate nonperformance by these counterparties.
The estimated fair values of the derivatives are determined by using available market information and appropriate valuation methods. Considerable judgment is required in interpreting market data to develop the estimates of fair value. Accordingly, the estimates presented herein are not necessarily indicative of the amounts that the Company could realize in a current market exchange.