Significant Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited, interim condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and, in management’s opinion, contain all adjustments (consisting of normal recurring items) necessary for a fair presentation, in all material respects, of the financial position and results of operations for the periods presented. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. The preparation of condensed financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions. Such estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Our operating results are subject to seasonal trends; therefore, the results of operations for the interim period ended September 30, 2020 are not necessarily indicative of the results that may be expected for the subsequent quarterly periods or the year ending December 31, 2020. The condensed financial statements should be read in conjunction with the financial statements and related notes, which appear in our Annual Report on Form 10-K for the year ended December 31, 2019. There have been no significant changes in the accounting principles and policies, long-term contracts or estimates inherent in the preparation of the condensed financial statements of Old Dominion Freight Line, Inc. as previously described in our Annual Report on Form 10-K for the year ended December 31, 2019, other than those disclosed in this Form 10-Q. Certain amounts in prior years have been reclassified to conform prior years’ financial statements to the current presentation. Unless the context requires otherwise, references in these Notes to “Old Dominion,” the “Company,” “we,” “us” and “our” refer to Old Dominion Freight Line, Inc.
Common Stock Split	Common Stock Split On February 21, 2020, we announced that our Board of Directors approved a three-for-two split of our common stock for shareholders of record as of the close of business on the record date of March 10, 2020. On March 24, 2020, those shareholders received one additional share of common stock for every two shares owned. In lieu of fractional shares, shareholders received a cash payment based on the average of the high and low sales prices of our common stock on the record date. All references in this report to shares outstanding, weighted average shares outstanding, earnings per share, and dividends per share amounts have been restated retroactively to reflect this stock split. Split-adjusted quarterly per-share metrics may not recalculate precisely due to rounding.
Short-term Investments	Short-term Investments The Company’s investments in certificates of deposit, U.S. government securities, and commercial paper with an original maturity of greater than three months have been classified and accounted for as trading securities, and are reported in “Short-term investments” on our Condensed Balance Sheet. These investments are measured at fair value each reporting period, with gains or losses recorded in “Non-operating expense (income)” on our Condensed Statement of Operations.
Fair Values of Financial Instruments	Fair Value of Financial Instruments 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. The levels of inputs used to measure fair value are: •Level 1 — Quoted prices for identical instruments in active markets; •Level 2 — Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets; and •Level 3 — Valuations based on inputs that are unobservable, generally utilizing pricing models or other valuation techniques that reflect management’s judgment and estimates. Our short-term investments and our long-term debt, including current maturities, are measured at fair value on a recurring basis, and are further described in Note 6. Our other financial securities in current assets and current liabilities approximate their fair value due to the short maturities of these instruments.
Stock Repurchase Program	Stock Repurchase Program On May 1, 2020, we announced that our Board of Directors had approved a new two-year stock repurchase program authorizing us to repurchase up to an aggregate of $700.0 million of our outstanding common stock (the “2020 Repurchase Program”). The 2020 Repurchase Program became effective upon the termination of our $350.0 million repurchase program on May 29, 2020, as of which date $21.5 million remained authorized under the prior program. Under the 2020 Repurchase Program, we may repurchase shares from time to time in open market purchases or through privately negotiated transactions. Shares of our common stock repurchased under our repurchase programs are canceled at the time of repurchase and are classified as authorized but unissued shares of our common stock. On May 29, 2020, we entered into an accelerated share repurchase agreement (the “ASR Agreement”) with a third-party financial institution as part of our 2020 Repurchase Program. Under the ASR Agreement, we paid the third-party financial institution $125.0 million and received an initial delivery of 511,427 shares of our common stock for $87.5 million, representing approximately 70% of the total value of shares to be received under the ASR Agreement. The remaining expected shares are scheduled to settle during the fourth quarter of 2020. At final settlement, we may receive additional shares of our common stock, or, under certain circumstances, we may be required to provide the third-party financial institution additional shares or may elect to make a cash payment to the third-party financial institution. The total shares repurchased will be based on the daily volume-weighted average share price of our common stock during the term of the ASR Agreement, less a negotiated discount. The ASR Agreement was accounted for as a settled treasury stock purchase and a forward stock purchase contract. The par value of the initial share delivery was recorded as a reduction to common stock, with the excess purchase price recorded as a reduction to retained earnings. The forward stock purchase contract is accounted for as a contract indexed to our own stock and is classified within capital in excess of par value on our Condensed Statements of Changes in Shareholders’ Equity. During the three months ended September 30, 2020, we did not repurchase any shares of our common stock. During the nine months ended September 30, 2020, we repurchased 2,237,320 shares of our common stock for $306.8 million under our repurchase programs, including shares repurchased under the ASR Agreement. As of September 30, 2020, we had $612.5 million remaining authorized under the 2020 Repurchase Program.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments – Credit Losses – Measurement of Credit Losses on Financial Statements” (Topic 326). This ASU modified the loss methodology for establishing a provision against financial assets, including customer receivables, to include an expected future performance component. We adopted ASU 2016-13 on January 1, 2020. The adoption did not have a material impact to our financial position, results of operations, or cash flow. We maintain an allowance for uncollectible accounts for estimated losses resulting from the inability of our customers to make required payments. We estimate this allowance by analyzing the aging of our customer receivables, our historical loss experience and other trends and factors affecting the credit risk of our customers, including anticipated changes to future performance. Write-offs occur when we determine an account to be uncollectible and could differ from our allowance estimate as a result of factors such as changes in the overall economic environment or risks surrounding our customers. Additional allowances may be required if the financial condition of our customers were to deteriorate, resulting in an impairment of their ability to make payments. We periodically review the underlying assumptions in our estimate of the allowance for uncollectible accounts to ensure that the allowance reflects the most recent trends and factors. Our allowance for uncollectible accounts was $4.9 million at September 30, 2020. There were no material write-offs to our allowance for uncollectible accounts during the third quarter of 2020.

Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2020

The accompanying unaudited, interim condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and, in management’s opinion, contain all adjustments (consisting of normal recurring items) necessary for a fair presentation, in all material respects, of the financial position and results of operations for the periods presented. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements.

The preparation of condensed financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions. Such estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Our operating results are subject to seasonal trends; therefore, the results of operations for the interim period ended September 30, 2020 are not necessarily indicative of the results that may be expected for the subsequent quarterly periods or the year ending December 31, 2020.

The condensed financial statements should be read in conjunction with the financial statements and related notes, which appear in our Annual Report on Form 10-K for the year ended December 31, 2019. There have been no significant changes in the accounting principles and policies, long-term contracts or estimates inherent in the preparation of the condensed financial statements of Old Dominion Freight Line, Inc. as previously described in our Annual Report on Form 10-K for the year ended December 31, 2019, other than those disclosed in this Form 10-Q.

Certain amounts in prior years have been reclassified to conform prior years’ financial statements to the current presentation.

Unless the context requires otherwise, references in these Notes to “Old Dominion,” the “Company,” “we,” “us” and “our” refer to Old Dominion Freight Line, Inc.

Common Stock Split

On February 21, 2020, we announced that our Board of Directors approved a three-for-two split of our common stock for shareholders of record as of the close of business on the record date of March 10, 2020. On March 24, 2020, those shareholders received one additional share of common stock for every two shares owned. In lieu of fractional shares, shareholders received a cash payment based on the average of the high and low sales prices of our common stock on the record date.

All references in this report to shares outstanding, weighted average shares outstanding, earnings per share, and dividends per share amounts have been restated retroactively to reflect this stock split. Split-adjusted quarterly per-share metrics may not recalculate precisely due to rounding.

Short-term Investments

The Company’s investments in certificates of deposit, U.S. government securities, and commercial paper with an original maturity of greater than three months have been classified and accounted for as trading securities, and are reported in “Short-term investments” on our Condensed Balance Sheet. These investments are measured at fair value each reporting period, with gains or losses recorded in “Non-operating expense (income)” on our Condensed Statement of Operations.

Fair Values of Financial Instruments

Fair Value of Financial Instruments

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. The levels of inputs used to measure fair value are:

•Level 1 — Quoted prices for identical instruments in active markets;

•Level 2 — Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets; and

•Level 3 — Valuations based on inputs that are unobservable, generally utilizing pricing models or other valuation techniques that reflect management’s judgment and estimates.

Our short-term investments and our long-term debt, including current maturities, are measured at fair value on a recurring basis, and are further described in Note 6. Our other financial securities in current assets and current liabilities approximate their fair value due to the short maturities of these instruments.

Stock Repurchase Program

On May 1, 2020, we announced that our Board of Directors had approved a new two-year stock repurchase program authorizing us to repurchase up to an aggregate of $700.0 million of our outstanding common stock (the “2020 Repurchase Program”). The 2020 Repurchase Program became effective upon the termination of our $350.0 million repurchase program on May 29, 2020, as of which date $21.5 million remained authorized under the prior program. Under the 2020 Repurchase Program, we may repurchase shares from time to time in open market purchases or through privately negotiated transactions. Shares of our common stock repurchased under our repurchase programs are canceled at the time of repurchase and are classified as authorized but unissued shares of our common stock.

On May 29, 2020, we entered into an accelerated share repurchase agreement (the “ASR Agreement”) with a third-party financial institution as part of our 2020 Repurchase Program. Under the ASR Agreement, we paid the third-party financial institution $125.0 million and received an initial delivery of 511,427 shares of our common stock for $87.5 million, representing approximately 70% of the total value of shares to be received under the ASR Agreement. The remaining expected shares are scheduled to settle during the fourth quarter of 2020. At final settlement, we may receive additional shares of our common stock, or, under certain circumstances, we may be required to provide the third-party financial institution additional shares or may elect to make a cash payment to the third-party financial institution. The total shares repurchased will be based on the daily volume-weighted average share price of our common stock during the term of the ASR Agreement, less a negotiated discount.

The ASR Agreement was accounted for as a settled treasury stock purchase and a forward stock purchase contract. The par value of the initial share delivery was recorded as a reduction to common stock, with the excess purchase price recorded as a reduction to retained earnings. The forward stock purchase contract is accounted for as a contract indexed to our own stock and is classified within capital in excess of par value on our Condensed Statements of Changes in Shareholders’ Equity.

During the three months ended September 30, 2020, we did not repurchase any shares of our common stock. During the nine months ended September 30, 2020, we repurchased 2,237,320 shares of our common stock for $306.8 million under our repurchase programs, including shares repurchased under the ASR Agreement. As of September 30, 2020, we had $612.5 million remaining authorized under the 2020 Repurchase Program.

Recent Accounting Pronouncements

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments – Credit Losses – Measurement of Credit Losses on Financial Statements” (Topic 326). This ASU modified the loss methodology for establishing a provision against financial assets, including customer receivables, to include an expected

future performance component. We adopted ASU 2016-13 on January 1, 2020. The adoption did not have a material impact to our financial position, results of operations, or cash flow.

We maintain an allowance for uncollectible accounts for estimated losses resulting from the inability of our customers to make required payments. We estimate this allowance by analyzing the aging of our customer receivables, our historical loss experience and other trends and factors affecting the credit risk of our customers, including anticipated changes to future performance. Write-offs occur when we determine an account to be uncollectible and could differ from our allowance estimate as a result of factors such as changes in the overall economic environment or risks surrounding our customers. Additional allowances may be required if the financial condition of our customers were to deteriorate, resulting in an impairment of their ability to make payments. We periodically review the underlying assumptions in our estimate of the allowance for uncollectible accounts to ensure that the allowance reflects the most recent trends and factors.

Our allowance for uncollectible accounts was $4.9 million at September 30, 2020. There were no material write-offs to our allowance for uncollectible accounts during the third quarter of 2020.