Dorman Products (DORM) 10-Q 29 Oct 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 26, 2020	Oct. 26, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 26, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	DORM
Title of 12(b) Security	Common stock, par value $0.01 per share
Security Exchange Name	NASDAQ
Entity Registrant Name	Dorman Products, Inc.
Entity Central Index Key	0000868780
Current Fiscal Year End Date	--12-26
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	0-18914
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	23-2078856
Entity Address, Address Line One	3400 East Walnut Street
Entity Address, City or Town	Colmar
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	18915
City Area Code	215
Local Phone Number	997-1800
Entity Common Stock, Shares Outstanding		32,286,697
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Income Statement [Abstract]
Net sales	$ 300,620	$ 253,796	$ 791,532	$ 751,762
Cost of goods sold	192,819	166,872	519,786	490,199
Gross profit	107,801	86,924	271,746	261,563
Selling, general and administrative expenses	63,028	59,961	184,288	177,637
Income from operations	44,773	26,963	87,458	83,926
Other (expense) income, net	(17)	33	2,317	90
Income before income taxes	44,756	26,996	89,775	84,016
Provision for income taxes	10,497	5,688	18,856	17,803
Net income	$ 34,259	$ 21,308	$ 70,919	$ 66,213
Earnings per share:
Basic	$ 1.06	$ 0.66	$ 2.19	$ 2.03
Diluted	$ 1.06	$ 0.65	$ 2.19	$ 2.02
Weighted average shares outstanding:
Basic	32,281	32,522	32,317	32,656
Diluted	32,371	32,594	32,394	32,738

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Current assets:
Cash and cash equivalents	$ 170,502	$ 68,353
Accounts receivable, less allowance for doubtful accounts of $1,202 and $957	405,312	391,810
Inventories	283,292	280,813
Prepaids and other current assets	11,769	13,614
Total current assets	870,875	754,590
Property, plant and equipment, net	94,217	101,837
Operating lease right-of-use assets	35,925	32,198
Goodwill	91,148	74,458
Intangible assets, net	26,054	21,305
Deferred tax asset, net	4,281	4,336
Other assets	36,333	52,348
Total assets	1,158,833	1,041,072
Current liabilities:
Accounts payable	112,757	90,437
Accrued compensation	17,731	9,782
Accrued customer rebates and returns	130,592	105,903
Other accrued liabilities	18,320	14,380
Total current liabilities	279,400	220,502
Long-term operating lease liabilities	34,433	29,730
Other long-term liabilities	9,629	13,297
Deferred tax liabilities, net	4,006	3,959
Commitments and contingencies
Shareholders’ Equity:
Common stock, par value $0.01; authorized 50,000,000 shares; issued and outstanding 32,304,686 and 32,558,168 in 2020 and 2019, respectively	324	326
Additional paid-in capital	56,893	52,605
Retained earnings	774,148	720,653
Total shareholders’ equity	831,365	773,584
Total liabilities and shareholders' equity	$ 1,158,833	$ 1,041,072

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts and customer credits	$ 1,202	$ 957
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	32,304,686	32,558,168
Common stock, shares outstanding	32,304,686	32,558,168

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 29, 2018	$ 727,623	$ 330	$ 47,861	$ 679,432
Beginning Balance, Shares at Dec. 29, 2018		33,004,861
Exercise of stock options	31		31
Exercise of stock options, shares		11,995
Compensation expense under Incentive Stock Plan	3,033		3,033
Purchase and cancellation of common stock	(24,339)	$ (3)	(522)	(23,814)
Purchase and cancellation of common stock, Shares		(290,274)
Issuance of non-vested stock, net of cancellations	868	$ 1	867
Issuance of non-vested stock, net of cancellations, Shares		70,885
Other stock related activity, net of tax	(837)		1,281	(2,118)
Other stock related activity, net of tax, Shares		(9,914)
Net income	66,213			66,213
Ending Balance at Sep. 28, 2019	772,592	$ 328	52,551	719,713
Ending Balance, Shares at Sep. 28, 2019		32,787,553
Beginning Balance at Dec. 29, 2018	$ 727,623	$ 330	47,861	679,432
Beginning Balance, Shares at Dec. 29, 2018		33,004,861
Purchase and cancellation of common stock, Shares	(22,380)
Ending Balance at Dec. 28, 2019	$ 773,584	$ 326	52,605	720,653
Ending Balance, Shares at Dec. 28, 2019	32,558,168	32,556,263
Beginning Balance at Jun. 29, 2019	$ 750,332	$ 328	51,514	698,490
Beginning Balance, Shares at Jun. 29, 2019		32,781,331
Exercise of stock options, shares		85
Compensation expense under Incentive Stock Plan	986		986
Issuance of non-vested stock, net of cancellations, Shares		6,593
Other stock related activity, net of tax	(34)		51	(85)
Other stock related activity, net of tax, Shares		(456)
Net income	21,308			21,308
Ending Balance at Sep. 28, 2019	772,592	$ 328	52,551	719,713
Ending Balance, Shares at Sep. 28, 2019		32,787,553
Beginning Balance at Dec. 28, 2019	$ 773,584	$ 326	52,605	720,653
Beginning Balance, Shares at Dec. 28, 2019	32,558,168	32,556,263
Exercise of stock options, shares		2,896
Compensation expense under Incentive Stock Plan	$ 3,966		3,966
Purchase and cancellation of common stock	$ (17,313)	$ (2)	(421)	(16,890)
Purchase and cancellation of common stock, Shares	(15,280)	(234,116)
Issuance of non-vested stock, net of cancellations	$ 504		504
Issuance of non-vested stock, net of cancellations, Shares		(14,782)
Other stock related activity, net of tax	(295)		239	(534)
Other stock related activity, net of tax, Shares		(5,575)
Net income	70,919			70,919
Ending Balance at Sep. 26, 2020	$ 831,365	$ 324	56,893	774,148
Ending Balance, Shares at Sep. 26, 2020	32,304,686	32,304,686
Beginning Balance at Jun. 27, 2020	$ 807,132	$ 326	55,406	751,400
Beginning Balance, Shares at Jun. 27, 2020		32,440,413
Exercise of stock options, shares		2,886
Compensation expense under Incentive Stock Plan	1,248		1,248
Purchase and cancellation of common stock	(11,448)	$ (1)	(244)	(11,203)
Purchase and cancellation of common stock, Shares		(135,787)
Issuance of non-vested stock, net of cancellations	(1)	$ (1)
Issuance of non-vested stock, net of cancellations, Shares		(2,937)
Other stock related activity, net of tax	175		483	(308)
Other stock related activity, net of tax, Shares		111
Net income	34,259			34,259
Ending Balance at Sep. 26, 2020	$ 831,365	$ 324	$ 56,893	$ 774,148
Ending Balance, Shares at Sep. 26, 2020	32,304,686	32,304,686

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash Flows from Operating Activities:
Net income	$ 70,919	$ 66,213
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation, amortization and accretion	22,544	21,011
Gain on equity method investment	(2,498)
Provision for doubtful accounts	197	33
Benefit for deferred income taxes	(1,154)	(302)
Provision for stock-based compensation	4,069	3,033
Changes in assets and liabilities:
Accounts receivable	(11,685)	28,276
Inventories	3,093	(12,231)
Prepaids and other current assets	1,360	(10,174)
Other assets	(1,923)	1,976
Accounts payable	20,334	(28,444)
Accrued customer rebates and returns	24,690	(8,312)
Accrued compensation and other liabilities	15,773	(1,429)
Cash provided by operating activities	145,719	59,650
Cash Flows from Investing Activities:
Acquisition, net of cash acquired	(14,308)
Property, plant and equipment additions	(12,061)	(24,656)
Cash used in investing activities	(26,369)	(24,656)
Cash Flows from Financing Activities:
Proceeds of revolving credit line	99,000
Payments of revolving credit line	(99,000)
Other stock related activity	112	57
Purchase and cancellation of common stock	(17,313)	(24,339)
Cash used in financing activities	(17,201)	(24,282)
Net Increase in Cash and Cash Equivalents	102,149	10,712
Cash and Cash Equivalents, Beginning of Period	68,353	43,458
Cash and Cash Equivalents, End of Period	170,502	54,170
Supplemental Cash Flow Information
Cash paid for interest expense	680	116
Cash paid for income taxes	$ 19,575	$ 28,454

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 26, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	1. Basis of Presentation As used herein, unless the context requires otherwise, “Dorman,” the “Company,” “we,” “us,” or “our” refers to Dorman Products, Inc. and its subsidiaries. Our ticker symbol on the NASDAQ Global Select Market is “DORM.” The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and in accordance with the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). However, they do not include all the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of only normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 26, 2020 are not necessarily indicative of the results that may be expected for the fiscal year ending 2020 or any future period. We may experience significant fluctuations from quarter to quarter in our results of operations due to the timing of orders placed by our customers. The introduction of new products and product lines to customers may cause significant fluctuations from quarter to quarter. These financial statements should be read in conjunction with the consolidated financial statements and footnotes thereto included in our Annual Report on Form 10-K for the fiscal year ended December 28, 2019. Certain prior year amounts have been reclassified to conform with current year presentation.

Business Acquisitions and Inves

Business Acquisitions and Investments	9 Months Ended
	Sep. 26, 2020
Business Combinations [Abstract]
Business Acquisitions and Investments	2. Business Acquisitions and Investments On January 2, 2020, we acquired the remaining 60% of the outstanding stock of Power Train Industries, Inc. (“PTI”), a privately-held supplier of parts to the automotive aftermarket, based in Reno, Nevada. The total consideration paid for PTI was approximately $30.7 million, which included $18.4 million paid for the remaining 60% of the outstanding stock, subject to customary purchase price adjustments, and $12.3 million which represents the fair value of the previously held 40% equity interest in PTI that was acquired by the Company in 2016. As a result of the acquisition, we recorded a gain of approximately $2.5 million in Other (expense) income, net during the nine months ended September 26, 2020 from the increase in fair value of the previously owned 40% interest in PTI. We previously accounted for our 40% interest as an equity-method investment. The transaction was accounted for as a business combination under the acquisition method of accounting. Accordingly, the assets acquired, and liabilities assumed were recorded at fair value, with the remaining purchase price recorded as goodwill. In connection with this acquisition, we recorded $16.7 million in goodwill, $7.3 million of identified intangibles, and $6.7 million of other assets, net, consisting of $3.5 million of cash, $2.0 million of accounts receivable, $5.6 million of inventory, The estimated fair value of the PTI assets acquired and liabilities assumed are provisional as of September 26, 2020 and are based on information that is currently available. Additional information about conditions that existed as of the date of acquisition are being gathered to finalize these provisional measurements, particularly with respect to net working capital and income taxes payable. Accordingly, the measurement of the PTI assets acquired and liabilities assumed may change upon completion of the purchase price allocation, both of which are expected to occur no later than one year from the acquisition date. The valuation of the intangible assets acquired and related amortization periods are as follows: (in thousands) Valuation Amortization Period (in years) Customer relationships $ 4,600 15 Trade names 700 5 Technology 1,800 8 Other 190 5 Total $ 7,290 The fair values of the customer relationships and trade names were estimated using an income approach based on the present value of future cash flows. The goodwill recognized is attributable primarily to strategic and synergistic opportunities related to existing automotive aftermarket businesses, the assembled workforce of PTI and other factors. The goodwill is not expected to be deductible for tax purposes. The financial results of the acquisition have been included in the condensed consolidated financial statements since the date of acquisition.

Sales of Accounts Receivable

Sales of Accounts Receivable	9 Months Ended
	Sep. 26, 2020
Receivables [Abstract]
Sales of Accounts Receivable	3. Sales of Accounts Receivable We have entered several customer sponsored programs administered by unrelated financial institutions that permit us to sell certain accounts receivable at discounted rates to the financial institutions. Transactions under these agreements were accounted for as sales of accounts receivable and the related accounts receivable were removed from our Condensed Consolidated Balance Sheet at the times of the sales transactions. Pursuant to these agreements, we sold $568.3

Inventories

Inventories	9 Months Ended
	Sep. 26, 2020
Inventory Disclosure [Abstract]
Inventories	4. Inventories Inventories include the cost of material, freight, direct labor and overhead utilized in the processing of our products and are stated at the lower of cost or net realizable value. Inventories were as follows: (in thousands) September 26, 2020 December 28, 2019 Bulk product $ 131,622 $ 114,308 Finished product 146,967 161,866 Packaging materials 4,703 4,639 Total $ 283,292 $ 280,813

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 26, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	5 . Goodwill and Intangible Assets Goodwill Goodwill included the following: (in thousands) September 26, 2020 December 28, 2019 Balance at beginning of period $ 74,458 $ 72,606 Goodwill acquired 16,690 — Measurement period adjustments — 1,852 Balance at end of period $ 91,148 $ 74,458 Intangible Assets Intangible assets included the following: September 26, 2020 December 28, 2019 Intangible assets subject to amortization Weighted Average Amortization Period Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value (in thousands) Trade names 10.8 $ 6,760 $ 1,432 $ 5,328 $ 6,060 $ 975 $ 5,085 Customer relationships 8.9 25,050 6,530 18,520 20,450 4,698 15,752 Technology 7.8 2,167 261 1,906 367 74 293 Other 3.6 430 130 300 240 65 175 Total $ 34,407 $ 8,353 $ 26,054 $ 27,117 $ 5,812 $ 21,305 Amortization expense was $0.8 million and $0.7 million for the three months ended September 26, 2020 and September 28, 2019, respectively, and $2.5 million and $2.0 million for the nine months ended September 26, 2020 and September 28, 2019, respectively .

Debt

Debt	9 Months Ended
	Sep. 26, 2020
Debt Disclosure [Abstract]
Debt	6 . Debt In March 2020, Dorman took proactive steps to increase its cash position and preserve financial flexibility in light of uncertainties from the COVID-19 pandemic by drawing down $99.0 million from its revolving credit facility available under its credit agreement. On June 29, 2020, the first day of our fiscal third quarter, the Company repaid the $99.0 million of outstanding borrowings under this revolving credit facility. T As of September 26, 2020, there were no borrowings under the credit agreement and two outstanding letters of credit for approximately $0.8 million in the aggregate which were issued to secure ordinary course of business transactions. Net of these letters of credit, there was approximately $99.2 million available under the credit agreement at September 26, 2020. As of September 26, 2020, we were not in default in respect to the credit agreement and paid $0.2 million and $0.4 million in interest during the three and nine months ended September 26, 2020, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 26, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies CBP Matter During 2019, we commenced a voluntary disclosure process in which we committed to disclosing to United States Customs & Border Protection (“CBP”) certain product misclassifications and reimbursing CBP for any resulting underpayment of duties that were identified as part of a voluntary internal review conducted by the Company. The Company recorded an estimated liability of $2.8 million in its Statement of Operations for the year ended December 28, 2019, which represents the Company’s estimated underpayment of duties, after deducting its estimated overpayment of duties, to CBP due to misclassifications over the prior five-year period, which is the applicable statute of limitations, plus applicable interest. In June 2020, we completed our internal review and submitted our prior disclosure statement to CBP, along with payment of $2.8 million for underpaid duties and interest. CBP has acknowledged receipt of our prior disclosure submission but has not yet communicated that our prior disclosure submission is closed. We intend to work cooperatively with CBP in connection with its review of our prior disclosure submission. Other Contingencies We are a party to or otherwise involved in legal proceedings that arise in the ordinary course of business, such as various claims and legal actions involving contracts, employment claims, competitive practices, intellectual property infringement, product liability claims and other matters arising out of the conduct of our business. In the opinion of management, none of the actions, individually or in the aggregate, taking into account relevant insurance coverage, would likely have a material financial impact on the Company, and we believe the range of reasonably possible losses from current matters, taking into account relevant insurance coverage, is immaterial. However, legal matters are subject to inherent uncertainties, and there exists the possibility that the ultimate resolution of any of these matters could have a material adverse impact on the Company’s cash flows, financial position and results of operations in the period in which any such effects are recorded.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 26, 2020
Revenue From Contract With Customer [Abstract]
Revenue Recognition	8 . Revenue Recognition Our primary source of revenue is from contracts with and purchase orders from customers. Revenue is recognized from product sales when goods are shipped, title and risk of loss and control have been transferred to the customer, and collection is probable. We estimate the transaction price at the inception of a contract or upon fulfilling a purchase order, including any variable consideration, and will update the estimate for changes in circumstances. We record estimates for cash discounts, product returns, promotional rebates, core (i.e., remanufactured parts) return deposits and other discounts (“customer rebates and returns”) in the period the related product revenue is recognized. The provision for customer rebates and returns is recorded as a reduction of gross sales. Our obligation associated with customer rebates and returns is classified as a current liability on our condensed consolidated balance sheets (“accrued customer rebates and returns”). Actual customer rebates and returns have not differed materially from estimated amounts for each period presented. Amounts billed to customers for shipping and handling are included in net sales. Costs associated with shipping and handling are included in cost of goods sold. We have concluded that our estimates of variable consideration are not constrained under revenue recognition requirements in accordance with GAAP. All our revenue was recognized under the point of time approach during the nine months ended September 26, 2020 and September 28, 2019, respectively. We do not have significant financing arrangements with our customers, as our credit terms are all 365 days or less. Also, we do not receive noncash consideration (such as materials or equipment) from our customers to facilitate the fulfillment of our contracts. Disaggregated Revenue The following tables present our disaggregated net sales by type of major good / product line, and geography. Three Months Ended Nine Months Ended (in thousands) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Powertrain $ 120,565 $ 104,756 $ 323,396 $ 299,730 Chassis 87,977 70,787 227,273 228,446 Automotive body 74,445 65,468 197,624 189,174 Hardware 17,633 12,785 43,239 34,412 Net sales $ 300,620 $ 253,796 $ 791,532 $ 751,762 Three Months Ended Nine Months Ended (in thousands) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Net sales to U.S. customers $ 280,330 $ 238,466 $ 744,285 $ 701,778 Net sales to non-U.S. customers 20,290 15,330 47,247 49,984 Net sales $ 300,620 $ 253,796 $ 791,532 $ 751,762

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 26, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	9 . Stock-Based Compensation Restricted Stock and Restricted Stock Units (“RSUs”) Vesting of restricted stock and RSU awards is conditional based on continued employment or service for a specified period and, in certain circumstances, the attainment of performance goals. With respect to restricted stock and RSU awards, we retain the shares underlying the award, and any dividends paid thereon, until the vesting conditions have been met. For time-based restricted stock and RSU awards, compensation cost related to the stock is recognized on a straight-line basis over the vesting period and is calculated using the closing price per share of our common stock on the grant date. For performance-based restricted stock and RSU awards tied to growth in adjusted pre-tax income, compensation cost related to the award is recognized over the performance period and is calculated using the closing price per share of our common stock on the grant date and an estimate of the probable outcome of the performance conditions at each reporting date. Since 2019, we have granted performance-based restricted stock and RSU awards that vest based on our total shareholder return ranking relative to the total shareholder return of the companies comprising the S&P Mid-Cap 400 Growth Index over a three-year performance period. For performance-based restricted stock and RSU awards tied to total shareholder return, compensation cost related to the award is recognized on a straight-line basis over the performance period and is calculated using the simulated fair value per share of our common stock based on the application of a Monte Carlo simulation model. Compensation cost related to restricted stock and RSU awards was $1.0 million and $0.8 million for the three months ended September 26, 2020 and September 28, 2019, respectively, and The following table summarizes our restricted stock and RSU award activity for the nine months ended September 26, 2020: Shares Weighted Average Price Balance at December 28, 2019 177,491 $ 76.70 Granted 82,905 $ 63.02 Vested (25,314 ) $ 70.89 Cancelled (27,703 ) $ 77.41 Balance at September 26, 2020 207,379 $ 71.84 As of September 26, 2020, there was Cash flows resulting from tax deductions in excess of the tax effect of compensation cost recognized in the financial statements are classified as operating cash flows. The excess tax benefit generated from restricted stock and RSU awards that vested was not significant during the nine months ended September 26, 2020 and September 28, 2019, respectively. Stock Options We expense the grant-date fair value of stock options as compensation on a straight-line basis over the vesting period for which related services are performed. The compensation cost charged against income was $0.3 million and $0.2 million for the three months ended September 26, 2020 and September 28, 2019, respectively, and $0.8 million and $0.5 million for the nine months ended September 26, 2020 and September 28, 2019, respectively. The compensation costs were classified as Selling, general and administrative expense in the Condensed Consolidated Statements of Operations. No cost was capitalized during the nine months ended September 26, 2020 or September 28, 2019. We use the Black-Scholes option valuation model to estimate the fair value of stock options granted. Expected volatility and expected dividend yield are based on the actual historical experience of our common stock. The expected life represents the period of time that options granted are expected to be outstanding and was calculated using historical option exercise data. The risk-free rate was based on a U.S. Treasury security with terms equal to the expected time of exercise as of the grant date. During the nine months ended September 26, 2020 and September 28, 2019, we granted 109,352 and 38,670 stock options, respectively. The following table summarizes our stock option activity for the nine months ended September 26, 2020: Shares Weighted Average Exercise Price Weighted Average Remaining Term (In years) Aggregate Intrinsic Value Balance at December 28, 2019 181,712 $ 70.78 Granted 109,352 $ 63.25 Forfeited (8,764 ) $ 65.24 Exercised (6,630 ) $ 56.52 Balance at September 26, 2020 275,670 $ 68.32 4.7 $ 4,695,637 Options exercisable at September 26, 2020 99,017 $ 65.99 2.2 $ 1,917,351 O ptions to purchase 6,630 and 35,401 shares of common stock were exercised during the nine months ended September 26, 2020 and September 28, 2019, respectively. As of September 26, 2020, there was $2.7 million Cash received from stock option exercises was not significant during the nine months ended September 26, 2020 and September 28, 2019. There was no excess tax benefit generated from stock options exercised in the nine months ended September 26, 2020 or September 28, 2019. Employee Stock Purchase Plan In May 2017, our shareholders approved the Dorman Products, Inc. Employee Stock Purchase Plan (the “ESPP”), which provides up to 1,000,000 shares of our common stock for sale to eligible employees. The purpose of the ESPP, which is qualified under Section 423 of the Internal Revenue Service Code of 1986, as amended, is to encourage stock ownership through payroll deductions and limited cash contributions by our employees. These contributions are used to purchase shares of the Company’s common stock at a 15% discount from the lower of the market price at the beginning or end of the purchase window. There were no $0.1 million

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 26, 2020
Earnings Per Share [Abstract]
Earnings Per Share	10 . Earnings Per Share Basic earnings per share is calculated by dividing our net income by the weighted average number of common shares outstanding during the period, which exclude unvested restricted stock and shares of our common stock underlying RSUs and stock options that are considered to be contingently issuable. To calculate diluted earnings per share, common share equivalents are added to the weighted average number of common shares outstanding. Common share equivalents are calculated using the treasury stock method and are computed based on outstanding stock-based awards. Stock-based awards of 141,000 shares and 96,000 shares were excluded from the calculation of diluted earnings per share as of September 26, 2020 and September 28, 2019, respectively, as their effect would have been anti-dilutive. The following table sets forth the computation of basic and diluted earnings per share: Three Months Ended Nine Months Ended (in thousands, except per share data) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Numerator Net income $ 34,259 $ 21,308 $ 70,919 $ 66,213 Denominator: Weighted average basic shares outstanding 32,281 32,522 32,317 32,656 Effect of stock-based compensation awards 90 72 77 82 Weighted average diluted shares outstanding 32,371 32,594 32,394 32,738 Earnings Per Share: Basic $ 1.06 $ 0.66 $ 2.19 $ 2.03 Diluted $ 1.06 $ 0.65 $ 2.19 $ 2.02

Common Stock Repurchases

Common Stock Repurchases	9 Months Ended
	Sep. 26, 2020
Text Block [Abstract]
Common Stock Repurchases	11 . Common Stock Repurchases We periodically repurchase, at the then current market price, and cancel shares of Dorman common stock issued to the Dorman Products, Inc. 401(k) Retirement Plan and Trust (the “401(k) Plan”). 401(k) Plan participants can no longer purchase shares of Dorman common stock as an investment option under the 401(k) Plan. Shares are purchased from the 401(k) Plan when participants sell units as permitted by the 401(k) Plan or elect to leave the 401(k) Plan upon retirement, termination or other reasons. For the nine months ended September 26, 2020 , we repurchased and cancelled 15,280 shares of common stock held in the 401(k) Plan for $ 1.1 million at an average price of $ 73.49 per share. During the year ended December 28, 2019 , we repurchased and cancelled 22,380 shares of common stock held in the 401(k) Plan for $ 1.9 million at an average price of $ 87.26 per share. Our Board of Directors authorized a share repurchase program of up to $400 million through December 31, 2020. Under this program, share repurchases may be made from time to time depending on market conditions, share price, share availability and other factors at our discretion. The share repurchase program does not obligate us to acquire any specific number of shares. For the nine months ended September 26, 2020, we repurchased and cancelled 218,836 shares of common stock for $16.2 million at an average price of $73.99 per share under this program. For the year ended December 28, 2019, we repurchased and cancelled 499,564 shares of common stock for $39.4 million at an average price of $78.84 per share under this program. At September 26, 2020, $127.7 million was available for repurchase under this share repurchase program. On October 27, 2020, the Company’s Board of Directors approved a resolution to increase and extend its share repurchase program by an additional $100 million, raising the aggregate authorization under the program to $500 million and extending it through December 31, 2022.

Related-Party Transactions

Related-Party Transactions	9 Months Ended
	Sep. 26, 2020
Related Party Transactions [Abstract]
Related-Party Transactions	12 . Related-Party Transactions We have a non-cancelable operating lease for a facility housing our corporate headquarters and a distribution center with a partnership in which Steven L. Berman, our Executive Chairman, and other members of the Berman family, are partners. Based upon the terms of the lease, payments will be $1.6 million in fiscal 2020 and $3.5 As of September 30, 2020, the beginning of our fourth quarter, another company in which Steven L. Berman, our Executive Chairman, and other members of the Berman family, are owners (the “Berman Real Estate Company”), acquired from an unaffiliated third-party owner the real estate and building which we were leasing from such third-party owner. In connection with the Berman Real Estate Company’s acquisition, we entered into a new non-cancelable operating lease agreement with the Berman Real Estate Company to continue leasing the facility. In the opinion of our Audit Committee, the terms and rates of this lease are no less favorable than those which could have been obtained from an unaffiliated party when the lease was entered into in September 2020. We also have non-cancelable operating leases with a limited liability company in which certain of the former owners of PTI are members. The leases were entered into prior to the January 2, 2020 acquisition of PTI by the Company, and they are used in the PTI business. Based upon the terms of the leases, aggregate payments thereunder will be $0.3 million in fiscal 2020. We are a partner in a joint venture with one of our suppliers and own minority interests in two other suppliers. Each of these investments is accounted for according to the equity method.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 26, 2020
Income Tax Disclosure [Abstract]
Income Taxes	13 . Income Taxes At September 26, 2020, we had $1.1 million of net unrecognized tax benefits, $1.0 million of which would lower our effective tax rate if recognized. We recognize interest and penalties related to uncertain tax positions in income tax expense. As of September 26, 2020, we had approximately $0.1 million of accrued interest and penalties related to uncertain tax positions. We file income tax returns in the United States, Canada, China, India, and Mexico. All years before 2016 are closed for United States federal tax purposes. Tax years before 2015 are closed for the states in which we file. Tax years before 2017 are closed for tax purposes in Canada. Tax years before 2016 are closed for tax purposes in China. Tax years before 2015 are closed for tax purposes in Mexico. All tax years remain open for India.

Fair Value Disclosures

Fair Value Disclosures	9 Months Ended
	Sep. 26, 2020
Fair Value Disclosures [Abstract]
Fair Value Disclosures	14 . Fair Value Disclosures The carrying value of financial instruments such as cash, accounts receivable, accounts payable, and other current assets and liabilities approximate their fair value based on the short-term nature of these instruments.

New and Recently Adopted Accoun

New and Recently Adopted Accounting Pronouncements	9 Months Ended
	Sep. 26, 2020
Accounting Changes And Error Corrections [Abstract]
New and Recently Adopted Accounting Pronouncements	15 . New and Recently Adopted Accounting Pronouncements In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment In June 2016, the FASB issued ASU 2016-13 , Financial Instruments – Credit Losses

New and Recently Adopted Acco_2

New and Recently Adopted Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 26, 2020
Accounting Changes And Error Corrections [Abstract]
New and Recently Adopted Accounting Pronouncements	In January 2017, the FASB issued ASU 2017-04, Simplifying the Test for Goodwill Impairment In June 2016, the FASB issued ASU 2016-13 , Financial Instruments – Credit Losses

Business Acquisitions and Inv_2

Business Acquisitions and Investments (Tables)	9 Months Ended
	Sep. 26, 2020
Power Train Industries, Inc. [Member]
Schedule of Valuation of Intangible Assets Acquired and Related Amortization Periods	The valuation of the intangible assets acquired and related amortization periods are as follows: (in thousands) Valuation Amortization Period (in years) Customer relationships $ 4,600 15 Trade names 700 5 Technology 1,800 8 Other 190 5 Total $ 7,290

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 26, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories include the cost of material, freight, direct labor and overhead utilized in the processing of our products and are stated at the lower of cost or net realizable value. Inventories were as follows: (in thousands) September 26, 2020 December 28, 2019 Bulk product $ 131,622 $ 114,308 Finished product 146,967 161,866 Packaging materials 4,703 4,639 Total $ 283,292 $ 280,813

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 26, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Goodwill Goodwill included the following: (in thousands) September 26, 2020 December 28, 2019 Balance at beginning of period $ 74,458 $ 72,606 Goodwill acquired 16,690 — Measurement period adjustments — 1,852 Balance at end of period $ 91,148 $ 74,458
Schedule of Intangible Assets	Intangible Assets Intangible assets included the following: September 26, 2020 December 28, 2019 Intangible assets subject to amortization Weighted Average Amortization Period Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value (in thousands) Trade names 10.8 $ 6,760 $ 1,432 $ 5,328 $ 6,060 $ 975 $ 5,085 Customer relationships 8.9 25,050 6,530 18,520 20,450 4,698 15,752 Technology 7.8 2,167 261 1,906 367 74 293 Other 3.6 430 130 300 240 65 175 Total $ 34,407 $ 8,353 $ 26,054 $ 27,117 $ 5,812 $ 21,305

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 26, 2020
Revenue From Contract With Customer [Abstract]
Summary of Disaggregated Net Sales	The following tables present our disaggregated net sales by type of major good / product line, and geography. Three Months Ended Nine Months Ended (in thousands) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Powertrain $ 120,565 $ 104,756 $ 323,396 $ 299,730 Chassis 87,977 70,787 227,273 228,446 Automotive body 74,445 65,468 197,624 189,174 Hardware 17,633 12,785 43,239 34,412 Net sales $ 300,620 $ 253,796 $ 791,532 $ 751,762 Three Months Ended Nine Months Ended (in thousands) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Net sales to U.S. customers $ 280,330 $ 238,466 $ 744,285 $ 701,778 Net sales to non-U.S. customers 20,290 15,330 47,247 49,984 Net sales $ 300,620 $ 253,796 $ 791,532 $ 751,762

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 26, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Restricted Stock and RSU Award Activity	The following table summarizes our restricted stock and RSU award activity for the nine months ended September 26, 2020: Shares Weighted Average Price Balance at December 28, 2019 177,491 $ 76.70 Granted 82,905 $ 63.02 Vested (25,314 ) $ 70.89 Cancelled (27,703 ) $ 77.41 Balance at September 26, 2020 207,379 $ 71.84
Summary of Stock Option Activity	The following table summarizes our stock option activity for the nine months ended September 26, 2020: Shares Weighted Average Exercise Price Weighted Average Remaining Term (In years) Aggregate Intrinsic Value Balance at December 28, 2019 181,712 $ 70.78 Granted 109,352 $ 63.25 Forfeited (8,764 ) $ 65.24 Exercised (6,630 ) $ 56.52 Balance at September 26, 2020 275,670 $ 68.32 4.7 $ 4,695,637 Options exercisable at September 26, 2020 99,017 $ 65.99 2.2 $ 1,917,351

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 26, 2020
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Earnings per Share	The following table sets forth the computation of basic and diluted earnings per share: Three Months Ended Nine Months Ended (in thousands, except per share data) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Numerator Net income $ 34,259 $ 21,308 $ 70,919 $ 66,213 Denominator: Weighted average basic shares outstanding 32,281 32,522 32,317 32,656 Effect of stock-based compensation awards 90 72 77 82 Weighted average diluted shares outstanding 32,371 32,594 32,394 32,738 Earnings Per Share: Basic $ 1.06 $ 0.66 $ 2.19 $ 2.03 Diluted $ 1.06 $ 0.65 $ 2.19 $ 2.02

Business Acquisitions and Inv_3

Business Acquisitions and Investments - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 02, 2020	Sep. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Business Acquisition [Line Items]
Business acquisition, goodwill		$ 91,148	$ 74,458	$ 72,606
Power Train Industries, Inc. [Member]
Business Acquisition [Line Items]
Fair value of previously held equity interest	$ 12,300
Equity method investment, ownership percentage	40.00%
Power Train Industries, Inc. [Member]
Business Acquisition [Line Items]
Business acquisition, percentage of outstanding stock acquired	60.00%
Total consideration paid for acquisition	$ 30,700
Business acquisition, value of outstanding stock acquired	18,400
Business combination, separately recognized transactions, net gains and losses		$ 2,500
Business acquisition, goodwill	16,700
Business acquisition, identified intangibles	7,290
Business acquisition, other net assets	6,700
Business acquisition, cash	3,500
Business acquisition, accounts receivables	2,000
Business acquisition, inventory	5,600
Business acquisition, other assets and liabilities net	$ 4,400

Business Acquisitions and Inv_4

Business Acquisitions and Investments - Schedule of Valuation of Intangible Assets Acquired and Related Amortization Periods (Detail) - Power Train Industries, Inc. [Member] $ in Thousands	Jan. 02, 2020USD ($)
Business Acquisition [Line Items]
Valuation,Intangible assets	$ 7,290
Customer Relationships [Member]
Business Acquisition [Line Items]
Valuation,Intangible assets	$ 4,600
Amortization Period (in years)	15 years
Trade Names [Member]
Business Acquisition [Line Items]
Valuation,Intangible assets	$ 700
Amortization Period (in years)	5 years
Technology [Member]
Business Acquisition [Line Items]
Valuation,Intangible assets	$ 1,800
Amortization Period (in years)	8 years
Other [Member]
Business Acquisition [Line Items]
Valuation,Intangible assets	$ 190
Amortization Period (in years)	5 years

Sales of Accounts Receivable -

Sales of Accounts Receivable - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Receivables [Abstract]
Sale of accounts receivable			$ 568.3	$ 530.7
Additional receivables outstanding if receivables had not been sold	$ 489.5		489.5		$ 437.9
Factoring costs associated with the sales of accounts receivable	$ 1.3	$ 4.3	$ 10.9	$ 13.6
Maximum credit terms allow to customers			365 days

Inventories - Inventories (Deta

Inventories - Inventories (Detail) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Inventory Disclosure [Abstract]
Bulk product	$ 131,622	$ 114,308
Finished product	146,967	161,866
Packaging materials	4,703	4,639
Total	$ 283,292	$ 280,813

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Balance at beginning of period	$ 74,458	$ 72,606
Goodwill acquired	16,690
Measurement period adjustments		1,852
Balance at end of period	$ 91,148	$ 74,458

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value	$ 34,407	$ 27,117
Accumulated Amortization	8,353	5,812
Net Carrying Value	$ 26,054	21,305
Trade Names [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	10 years 9 months 18 days
Gross Carrying Value	$ 6,760	6,060
Accumulated Amortization	1,432	975
Net Carrying Value	$ 5,328	5,085
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	8 years 10 months 24 days
Gross Carrying Value	$ 25,050	20,450
Accumulated Amortization	6,530	4,698
Net Carrying Value	$ 18,520	15,752
Technology [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	7 years 9 months 18 days
Gross Carrying Value	$ 2,167	367
Accumulated Amortization	261	74
Net Carrying Value	$ 1,906	293
Other [Member]
Finite Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	3 years 7 months 6 days
Gross Carrying Value	$ 430	240
Accumulated Amortization	130	65
Net Carrying Value	$ 300	$ 175

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 0.8	$ 0.7	$ 2.5	$ 2

Debt - Additional Information (

Debt - Additional Information (Detail)	Jun. 29, 2020USD ($)	Mar. 31, 2020USD ($)	Sep. 26, 2020USD ($)LetterOfCredit	Sep. 26, 2020USD ($)LetterOfCredit
Debt Instrument [Line Items]
Amount drawn from credit facility				$ 99,000,000
Amount of outstanding borrowings credit facility repaid				$ 99,000,000
Debt weighted average interest rate			1.41%	1.41%
Number of letters of credit outstanding | LetterOfCredit			2	2
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Amount drawn from credit facility		$ 99,000,000
Amount of outstanding borrowings credit facility repaid	$ 99,000,000
Borrowings under credit facility			$ 0	$ 0
Amount available under credit facility, net of letters of credit			99,200,000	99,200,000
Credit facility default amount			0	0
Interest paid			200,000	400,000
Letters of Credit [Member]
Debt Instrument [Line Items]
Borrowings under credit facility			$ 800,000	$ 800,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 28, 2019
Commitments And Contingencies Disclosure [Abstract]
Estimated underpayment of duties amount		$ 2.8
Payment of underpaid duties and interest	$ 2.8

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Detail)	9 Months Ended
	Sep. 26, 2020
Revenue From Contract With Customer [Abstract]
Maximum credit terms allow to customers	365 days

Revenue Recognition - Summary o

Revenue Recognition - Summary of Disaggregated Net Sales (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Disaggregation Of Revenue [Line Items]
Net Sales	$ 300,620	$ 253,796	$ 791,532	$ 751,762
U.S. Customers [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	280,330	238,466	744,285	701,778
Non-U.S. Customers [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	20,290	15,330	47,247	49,984
Powertrain [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	120,565	104,756	323,396	299,730
Chassis [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	87,977	70,787	227,273	228,446
Automotive Body [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	74,445	65,468	197,624	189,174
Hardware [Member]
Disaggregation Of Revenue [Line Items]
Net Sales	$ 17,633	$ 12,785	$ 43,239	$ 34,412

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2017	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost related to stock options		$ 300,000	$ 200,000	$ 800,000	$ 500,000
Stock options granted				109,352
Stock options exercised				6,630
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Authorized number of common stock shares for grant	1,000,000
Rate of discount on shares of common stock available for sale to eligible employees	15.00%
Number of shares purchased		0	0	10,735	13,669
Compensation cost		$ 100,000	$ 100,000	$ 300,000	$ 200,000
Restricted Stock and Restricted Stock Units Award [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation cost related to restricted stock		1,000,000	$ 800,000	3,000,000	2,300,000
Unrecognized compensation cost related to non-vested stock options		7,900,000		$ 7,900,000
Unrecognized compensation cost related to nonvested stock options, weighted-average period				2 years 6 months
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested stock options		$ 2,700,000		$ 2,700,000
Unrecognized compensation cost related to nonvested stock options, weighted-average period				2 years 10 months 24 days
Capitalized compensation cost				$ 0	$ 0
Stock options granted				109,352	38,670
Stock options exercised				6,630	35,401
Tax benefit generated from compensation cost and credited				$ 0	$ 0

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Restricted Stock and RSU Award Activity (Detail)	9 Months Ended
	Sep. 26, 2020$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Beginning Balance, Shares | shares	177,491
Granted, Shares | shares	82,905
Vested, Shares | shares	(25,314)
Cancelled, Shares | shares	(27,703)
Ending Balance, Shares | shares	207,379
Beginning Balance, Weighted Average Price | $ / shares	$ 76.70
Granted, Weighted Average Price | $ / shares	63.02
Vested, Weighted Average Price | $ / shares	70.89
Cancelled, Weighted Average Price | $ / shares	77.41
Ending Balance, Weighted Average Price | $ / shares	$ 71.84

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock Option Activity (Detail)	9 Months Ended
	Sep. 26, 2020USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Beginning Balance, Shares | shares	181,712
Granted, Shares | shares	109,352
Forfeited, Shares | shares	(8,764)
Exercised, Shares | shares	(6,630)
Ending Balance, Shares | shares	275,670
Options Exercisable, Shares | shares	99,017
Beginning Balance, Weighted Average Exercise Price | $ / shares	$ 70.78
Granted, Weighted Average Exercise Price | $ / shares	63.25
Forfeited, Weighted Average Exercise Price | $ / shares	65.24
Exercised, Weighted Average Exercise Price | $ / shares	56.52
Ending Balance, Weighted Average Exercise Price | $ / shares	68.32
Options Exercisable, Weighted Average Exercise Price | $ / shares	$ 65.99
Ending Balance, Weighted Average Remaining Terms (years)	4 years 8 months 12 days
Options Exercisable, Weighted Average Remaining Terms (years)	2 years 2 months 12 days
Ending Balance, Aggregate Intrinsic Value | $	$ 4,695,637
Options Exercisable, Aggregate Intrinsic Value | $	$ 1,917,351

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Earnings Per Share [Abstract]
Stock-based awards considered as anti-dilutive	141,000	96,000

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Computation of Basic and Diluted Earnings per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Numerator
Net income	$ 34,259	$ 21,308	$ 70,919	$ 66,213
Denominator:
Weighted average basic shares outstanding	32,281	32,522	32,317	32,656
Effect of stock-based compensation awards	90	72	77	82
Weighted average diluted shares outstanding	32,371	32,594	32,394	32,738
Earnings Per Share:
Basic	$ 1.06	$ 0.66	$ 2.19	$ 2.03
Diluted	$ 1.06	$ 0.65	$ 2.19	$ 2.02

Common Stock Repurchases - Addi

Common Stock Repurchases - Additional Information (Detail) - USD ($)	Oct. 27, 2020	Sep. 26, 2020	Dec. 28, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repurchased and cancelled shares		15,280	22,380
Common stock repurchased, value		$ 1,100,000	$ 1,900,000
Common stock repurchased, average price		$ 73.49	$ 87.26
Share repurchase program shares authorized to be repurchased expiration date		Dec. 31, 2020
Share Repurchase Program [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Repurchased and cancelled shares		218,836	499,564
Common stock repurchased, value		$ 16,200,000	$ 39,400,000
Common stock repurchased, average price		$ 73.99	$ 78.84
Share repurchase program shares authorized to be repurchased		$ 400,000,000
Shares available for repurchase under share repurchase program amount		$ 127,700,000
Share Repurchase Program [Member] | Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share repurchase program shares authorized to be repurchased	$ 500,000,000
Share repurchase program shares authorized to be repurchased expiration date	Dec. 31, 2022
Share repurchase program, increase in authorized amount	$ 100,000,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 26, 2020USD ($)Supplier	Dec. 26, 2020USD ($)	Dec. 28, 2019USD ($)
Related Party Transaction [Line Items]
Rental payments based upon the terms of the lease			$ 1,600
Right-of-use asset	$ 35,925		$ 32,198
Lease expiration date	Dec. 31, 2022
Scenario, Forecast [Member]
Related Party Transaction [Line Items]
Rental payments based upon the terms of the lease		$ 1,600
Scenario, Forecast [Member] | Power Train Industries, Inc. [Member]
Related Party Transaction [Line Items]
Rental payments based upon the terms of the lease		$ 300
Steven L. Berman and Other Family Members [Member]
Related Party Transaction [Line Items]
Right-of-use asset	$ 3,500
Lease liabilities	$ 3,500
Joint Venture [Member]
Related Party Transaction [Line Items]
Minority interests in number of suppliers | Supplier	2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) $ in Millions	Sep. 26, 2020USD ($)
Income Tax Disclosure [Abstract]
Net unrecognized tax benefits	$ 1.1
Unrecognized tax benefits which would lower effective tax rate if recognized	1
Accrued interest and penalties related to uncertain tax positions	$ 0.1

New and Recently Adopted Acco_3

New and Recently Adopted Accounting Pronouncements - Additional Information (Detail)	Sep. 26, 2020
ASU 2017-04
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Dec. 29, 2019
ASU 2016-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Dec. 29, 2019