Year Ended December 31, 2020 2019 2018 (Amounts in thousands) Loss recorded in AOCL (34,973) (12,084) (17,164) We use the spot method to measure the effectiveness of both of the net investment hedges and evaluate the effectiveness on a prospective basis at the beginning of each quarter. W e did not record any ineffectiveness for the years ended December 31, 2020, 2019 or 2018. Our financial instruments are presented at fair value in our consolidated balance sheets. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Where available, fair value is based on observable market prices or parameters or derived from such prices or parameters. Where observable prices or inputs are not available, valuation models may be applied. Assets and liabilities recorded at fair value in our consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Recurring fair value measurements are limited to investments in derivative instruments and some equity securities. The fair value measurements of our derivative instruments are determined using models that maximize the use of the observable market inputs including interest rate curves and both forward and spot prices for currencies, and are classified as Level II under the fair value hierarchy. The fair values of our derivatives are included above in Note 9. The fair value measurements of our investments in equity securities are determined using quoted market prices and are classified as Level I. The fair values of our investments in equity securities, and changes thereto, are immaterial to our consolidated financial position and results of operations. The carrying value of our debt is included in Note 13 and, except for the Senior Notes, approximates fair value. The estimated fair value of the Senior Notes is based on Level I quoted market rates. The estimated fair value of our Senior Notes at December 31, 2020 was $1,778.4 million compared to the carrying value of $1,701.5 million. The  carrying amounts of our other financial instruments (i.e., cash and cash equivalents, accounts receivable, net and accounts payable) approximated fair value due to their short-term nature at December 31, 2020 and December 31, 2019. The following tables present financial information of certain consolidated balance sheet captions. 10. FAIR VALUE OF FINANCIAL INSTRUMENTS 11. DETAILS OF CERTAIN CONSOLIDATED BALANCE SHEET CAPTIONS December 31, 2020 2019 (Amounts in thousands) Trade accounts receivables $ 808,459  $ 830,919  Less: allowance for doubtful accounts (59,280) (47,269) Other short-term receivables 20,179  18,031  Less: allowance for doubtful accounts (15,896) (6,143) Accounts receivable, net $ 753,462  $ 795,538  Accounts Receivable, net  — Accounts receivable, net were: 87