Heritage-Crystal Clean (HCCI) 10-Q 2 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 23, 2019	Apr. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	Heritage-Crystal Clean, Inc.
Entity Central Index Key	0001403431
Current Fiscal Year End Date	--12-28
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 23, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		23,125,474
Entity Emerging Growth Company	false
Entity Small Business	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 23, 2019	Dec. 29, 2018
Current assets:
Cash and cash equivalents	$ 42,692	$ 43,579
Accounts receivable - net	53,326	51,744
Inventory - net	29,661	33,059
Other current assets	4,914	6,835
Total current assets	130,593	135,217
Property, plant and equipment - net	144,796	139,987
Right of use assets	62,929
Equipment at customers - net	23,839	23,814
Software and intangible assets - net	17,070	14,681
Goodwill	32,358	34,123
Total assets	411,585	347,822
Current liabilities:
Accounts payable	34,858	32,630
Current portion of lease liabilities	18,433
Contract liabilities - net	2,399	166
Accrued salaries, wages, and benefits	4,483	6,024
Taxes payable	6,290	6,120
Other current liabilities	5,986	5,089
Total current liabilities	72,449	50,029
Lease liabilities, net of current portion	44,298
Long-term debt	29,116	29,046
Deferred income taxes	13,544	14,516
Total liabilities	159,407	93,591
STOCKHOLDERS' EQUITY:
Common stock - 26,000,000 shares authorized at $0.01 par value, 23,120,998 shares and 23,058,584 shares issued and outstanding at March 23, 2019 and December 29, 2018, respectively	231	231
Additional paid-in capital	197,909	197,533
Retained earnings	53,307	55,819
Total Heritage-Crystal Clean, Inc. stockholders' equity	251,447	253,583
Noncontrolling interest	731	648
Total equity	252,178	254,231
Total liabilities and stockholders' equity	$ 411,585	$ 347,822

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 23, 2019	Dec. 29, 2018
Statement of Financial Position [Abstract]
Common stock, shares authorized (in shares)	26,000,000	26,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares issued (in shares)	23,120,998	23,058,584
Common stock, shares outstanding (in shares)	23,120,998	23,058,584

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income/(Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018
Revenues
Rental income	$ 3,548	$ 0
Total revenues	95,772	83,147
Operating expenses
Operating costs	82,483	68,386
Selling, general, and administrative expenses	12,396	11,022
Depreciation and amortization	4,136	3,643
Other (income) expense - net	(58)	389
Operating loss	(3,185)	(293)
Interest expense – net	230	245
Loss before income taxes	(3,415)	(538)
Benefit from income taxes	(986)	(436)
Net loss	(2,429)	(102)
Income attributable to noncontrolling interest	83	18
Net loss attributable to Heritage-Crystal Clean, Inc. common stockholders	$ (2,512)	$ (120)
Net loss per share: basic (in dollars per share)	$ (0.11)	$ (0.01)
Net loss per share: diluted (in dollars per share)	$ (0.11)	$ (0.01)
Number of weighted average shares outstanding: basic (in shares)	23,117	22,962
Number of weighted average shares outstanding: diluted (in shares)	23,117	22,962
Service revenues
Revenues
Total revenues	$ 56,366	$ 54,137
Product revenues
Revenues
Total revenues	$ 35,858	$ 29,010

Condensed Consolidated Statem_2

Condensed Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional Paid–in Capital	Retained Earnings	Total Heritage-Crystal Clean, Inc. Stockholders' Equity	Non-controlling Interest
Beginning balance (in shares) at Dec. 30, 2017		22,891,674
Beginning balance at Dec. 30, 2017	$ 235,926	$ 229	$ 193,640	$ 41,359	$ 235,228	$ 698
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(102)			(120)	(120)	18
Issuance of common stock – ESPP (in shares)		4,822
Issuance of common stock – ESPP	100		100		100
Share-based compensation (in shares)		114,237
Share-based compensation	828	$ 1	827		828
Share repurchases to satisfy tax withholding obligations	(1,031)		(1,031)		(1,031)
Ending balance (in shares) at Mar. 24, 2018		23,010,733
Ending balance at Mar. 24, 2018	$ 235,453	$ 230	193,536	40,971	234,737	716
Beginning balance (in shares) at Dec. 29, 2018	23,058,584	23,058,584
Beginning balance at Dec. 29, 2018	$ 254,231	$ 231	197,533	55,819	253,583	648
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(2,429)			(2,512)	(2,512)	83
Issuance of common stock – ESPP (in shares)		4,975
Issuance of common stock – ESPP	$ 111		111		111
Exercise of stock options (in shares)	2,760	2,760
Exercise of stock options	$ 20		20		20
Share-based compensation (in shares)		54,679
Share-based compensation	889		889		889
Share repurchases to satisfy tax withholding obligations	$ (644)		(644)		(644)
Ending balance (in shares) at Mar. 23, 2019	23,120,998	23,120,998
Ending balance at Mar. 23, 2019	$ 252,178	$ 231	$ 197,909	$ 53,307	$ 251,447	$ 731

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Cash flows from Operating Activities:
Net loss	$ (2,429)	$ (102)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	4,136	3,643
Bad debt provision	249	286	$ 628
Share-based compensation	889	828
Deferred taxes	(972)	(386)
Other, net	(171)	74
Changes in operating assets and liabilities:
Increase in accounts receivable	(1,473)	(1,678)
Decrease (increase) in inventory	3,716	(3,755)
Decrease in other current assets	1,921	773
Increase in accounts payable	1,531	2,344
Increase (decrease) in accrued liabilities	1,781	(2,564)
Cash provided by (used in) operating activities	9,178	(537)
Cash flows from Investing Activities:
Capital expenditures	(7,579)	(3,568)
Business acquisitions, net of cash acquired	(1,973)	0
Proceeds from the disposal of assets	0	55
Cash used in investing activities	(9,552)	(3,513)
Cash flows from Financing Activities:
Proceeds from the exercise of stock options	20	0
Share repurchases to satisfy tax withholding obligations	(644)	(382)
Proceeds from the issuance of common stock	111	100
Cash used in financing activities	(513)	(282)
Net decrease in cash and cash equivalents	(887)	(4,332)
Cash and cash equivalents, beginning of period	43,579	41,889	41,889
Cash and cash equivalents, end of period	42,692	37,557	$ 43,579
Supplemental disclosure of cash flow information:
Income taxes paid	0	2
Cash paid for interest	334	249
Supplemental disclosure of non-cash information:
Payables for construction in progress	1,933	451
Payables for share-based tax withholdings	$ 0	$ 649

Organization and Nature of Oper

Organization and Nature of Operations	3 Months Ended
	Mar. 23, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Operations	ORGANIZATION AND NATURE OF OPERATIONS Heritage-Crystal Clean, Inc., a Delaware corporation and its subsidiaries (collectively the “Company”), provide parts cleaning, hazardous and non-hazardous containerized waste, used oil collection, vacuum, antifreeze recycling and field services primarily to small and mid-sized industrial and vehicle maintenance customers. The Company owns and operates a used oil re-refinery where it re-refines used oils and sells high quality base oil for lubricants as well as other re-refinery products. The Company also has multiple locations where it dehydrates used oil. The oil processed at these locations is sold as recycled fuel oil. The Company also operates multiple wastewater treatment plants and antifreeze recycling facilities at which it produces virgin-quality antifreeze. The Company's locations are in the United States and Ontario, Canada. The Company conducts its primary business operations through Heritage-Crystal Clean, LLC, its wholly owned subsidiary, and all intercompany balances have been eliminated in consolidation. The Company has two reportable segments: "Environmental Services" and "Oil Business." The Environmental Services segment consists of the Company's parts cleaning, containerized waste management, vacuum truck services, antifreeze recycling activities, and field services. The Oil Business segment consists of the Company's used oil collection, recycled fuel oil sales, used oil re-refining activities, and used oil filter removal and disposal services. No customer represented greater than 10% of consolidated revenues for any of the periods presented. There were no intersegment revenues. Both segments operate in the United States and, to an immaterial degree, in Ontario, Canada. As such, the Company is not disclosing operating results by geographic segment. The Company’s fiscal year ends on the Saturday closest to December 31. The most recent fiscal year ended on December 29, 2018. Each of the Company's first three fiscal quarters consists of twelve weeks while the last fiscal quarter consists of sixteen or seventeen weeks. In the Company's Environmental Services segment, product revenues include sales of solvent, machines, absorbent, accessories, and antifreeze; service revenues include servicing of parts cleaning machines, drum waste removal services, vacuum truck services, field services, and other services. In the Company's Oil Business segment, product revenues primarily consist of sales of re-refined base oil, re-refinery co-products and recycled fuel oil; service revenues include revenues from used oil collection activities, collecting and disposing of waste water and removal and disposal of used oil filters. Due to the Company's integrated business model, it is impracticable to separately present costs of tangible products and costs of services.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 23, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The Company's significant accounting policies are described in Note 2, "Summary of Significant Accounting Policies," in the Company's Annual Report on Form 10-K for the fiscal year ended December 29, 2018. There have been no material changes in these policies or their application during the first quarter of fiscal 2019 with the exception of our accounting for leases. See footnote 12 — Commitments and Contingencies for more information. Recently Issued Accounting Pronouncements Standard Issuance Date Description Our Effective Date Effect on the Financial Statements ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” June 2016 This update modifies the impairment model for most financial assets and certain other instruments. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities will be required to utilize a new forward-looking “expected loss” methodology that generally will result in the earlier recognition of allowance for losses. December 29, 2019 The Company is evaluating the impact this new standard would have on our consolidated financial statements. Recently Issued Accounting Standards Adopted Standard Issuance Date Description Effective Date Effect on the Financial Statements ASU 2016-02 February 2016 This update was issued to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Early application of the amendments in this update is permitted for all entities. December 30, 2018 The Company adopted the new leasing standard ASC 842 "Leases" on December 30, 2018. ASU 2016-02 provides for a modified retrospective transition approach requiring lessees to recognize and measure leases on the balance sheet at the beginning of either the earliest period presented or as of the beginning of the period of adoption. The Company elected to apply ASU 2016-02 as of the beginning of the period of adoption (December 30, 2018) and will not restate comparative periods. The adoption resulted in the recognition of $63.3 million of right of use assets and $63.3 million of lease liabilities. The Company recognized approximately $2.2 million of deferred rental income from certain embedded leases during the first quarter of 2019. Effective December 30, 2018, the Company adopted the requirements of Topic 842. The cumulative effects of the changes made to our Statement of Income and Balance Sheet are as follows: For the First Quarter Ended, March 23, 2019 As Reported Balances Without Adoption of Topic 842 Effect of Change (thousands) Higher/(Lower) Statement of Income Service revenues $ 56,366 $ 62,116 $ (5,750 ) Rental income 3,548 — 3,548 Total revenues 95,772 97,974 (2,202 ) Operating loss (3,185 ) (983 ) (2,202 ) Loss before income taxes (3,415 ) (1,213 ) (2,202 ) Net loss (2,429 ) (862 ) (1,567 ) Net loss attributable to Heritage-Crystal Clean, Inc. common stockholders $ (2,512 ) $ (945 ) $ (1,567 ) Net loss per share: basic $ (0.11 ) $ (0.04 ) $ (0.07 ) Net loss per share: diluted $ (0.11 ) $ (0.04 ) $ (0.07 ) March 23, 2019 As Reported Balances Without Adoption of Topic 842 Effect of Change (thousands) Higher/(Lower) Balance Sheet Right of use assets $ 62,929 $ — $ 62,929 Total assets 411,585 348,656 62,929 Current portion of lease liabilities 18,433 — 18,433 Contract liabilities - net 2,399 197 2,202 Other current liabilities 5,986 5,788 198 Total current liabilities 72,449 51,616 20,833 Lease liabilities, net of current portion 44,298 — 44,298 Deferred income taxes 13,544 14,179 (635 ) Total liabilities 159,407 94,911 64,496 Retained earnings 53,307 54,874 (1,567 ) Heritage-Crystal Clean, Inc. stockholders' equity $ 251,447 $ 253,014 $ (1,567 ) Total equity $ 252,178 $ 253,745 $ (1,567 ) Total liabilities and stockholders' equity $ 411,585 $ 348,656 $ 62,929

Business Combinations

Business Combinations	3 Months Ended
	Mar. 23, 2019
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS On January 11, 2019, the Company purchased the assets of the consumer division of GlyEco, Inc. ("GlyEco") pursuant to an Asset Purchase Agreement. The Company purchased the assets of GlyEco's consumer division to expand the Company’s antifreeze line of business while expanding geographically. The purchase price was set at $1.6 million subject to certain adjustments, including working capital adjustments, and is preliminarily allocated based on our estimates and assumptions of the approximate fair values of assets acquired on the acquisition date. We are still in the process of completing our valuation, and accordingly our estimates and assumptions are subject to change within the measurement period. The Company is continuing to examine facts and circumstances that existed at the acquisition date and how those affect the estimated fair value of working capital, and the allocation of the estimated purchase price to other tangible and intangible assets. The results of GlyEco are consolidated into the Company’s Environmental Services segment. On February 1, 2019, the Company purchased the assets of W.S. Supplies, Inc. ("WSS") pursuant to an Asset Purchase Agreement. The Company purchased the assets of WSS to expand the Company’s Environmental Services segment in the mid-west. The purchase price was set at $0.5 million subject to certain adjustments, including a contingent consideration provision, and is preliminarily allocated based on our estimates and assumptions of the approximate fair values of assets acquired on the acquisition date.We are still in the process of completing our valuation, and accordingly our estimates and assumptions are subject to change within the measurement period. The Company is continuing to examine facts and circumstances that existed at the acquisition date and how those affect the estimated fair value of working capital, and the allocation of the estimated purchase price to other tangible and intangible assets. The results of WSS are consolidated into the Company’s Environmental Services segment. On May 3, 2018, the Company purchased the assets of Products Plus, Inc. and AO Holding Company-Kansas City, LLC (collectively "PPI") pursuant to an Asset Purchase Agreement. The Company purchased the assets of PPI to expand the Company’s market share in the collection, recycling, and sales of a full line of antifreeze products. The purchase price was set at $5.9 million subject to certain adjustments, including a working capital adjustment and a contingent consideration provision. During the measurement period, the Company finalized the purchase price allocation of the PPI business combination. Compared to the provisional values reported as of December 29, 2018, the fair values presented in the table below reflect increases to property, plant, & equipment of $0.2 million and other intangible assets of $1.5 million . Compared to the provisional values reported as of December 29, 2018, the finalized fair values presented in the table below reflect decreases to contingent consideration of $0.1 million and goodwill of $1.8 million . Contingent consideration to be paid subsequent to March 23, 2019 is contingent upon several business performance metrics over the three -year period starting with the acquisition date and ending May 3, 2021. The range of the potential contingent consideration, which is to be paid out subsequent to March 23, 2019, is between zero to $1.5 million . Goodwill recognized from the acquisition of PPI represents the excess of the estimated purchase consideration transferred over the estimated fair value of the assets acquired. Factors leading to goodwill being recognized are the Company's expectations of synergies from combining operations of PPI and the Company as well as the value of intangible assets that are not separately recognized, such as assembled workforce. The results of PPI are consolidated into the Company’s Environmental Services segment. On June 11, 2018, the Company purchased the assets of Kurt Lanse d/b/a Hot Tank Supply Company ("HTSC") pursuant to an Asset Purchase Agreement. The Company purchased the assets of HTSC to expand the Company’s market share in California. The purchase price was set at $0.7 million subject to certain adjustments, including a working capital adjustment and a deferred and contingent consideration provision, and is preliminarily allocated based on our estimates and assumptions of the approximate fair values of assets acquired on the acquisition date. We are still in the process of completing our valuation, and accordingly our estimates and assumptions are subject to change within the measurement period. The Company is continuing to examine facts and circumstances that existed at the acquisition date and how those affect the estimated fair value of contingent consideration, working capital, and the allocation of the estimated purchase price to other tangible and intangible assets. The Company estimates that contingent consideration to be paid subsequent to March 23, 2019 will be approximately $0.1 million . Goodwill recognized from the acquisition of HTSC represents the excess of the estimated purchase consideration transferred over the estimated fair value of the assets acquired. Factors leading to goodwill being recognized are the Company's expectations of synergies from combining operations of HTSC and the Company as well as the value of intangible assets that are not separately recognized, such as assembled workforce. The results of HTSC are consolidated into the Company’s Environmental Services segment. The following table summarizes the estimated fair values of the assets acquired, some of which are preliminary, related to each acquisition: As of March 23, 2019 (thousands) GlyEco WSS PPI HTSC Accounts receivable $ 359 $ — $ 909 $ 40 Inventory 290 28 259 3 Property, plant, & equipment 746 154 2,154 47 Equipment at customers — 24 — 104 Intangible assets 251 298 2,001 100 Goodwill — — 406 377 Total purchase price, net of cash acquired $ 1,646 $ 504 $ 5,729 $ 671 Less: working capital adjustment 23 14 (62 ) (9 ) Less: deferred consideration — — — 225 Less: contingent consideration — 90 1,341 100 Less: to be placed in escrow — 50 — — Net cash paid $ 1,623 $ 350 $ 4,450 $ 355 Unaudited Pro-forma Financial Information Pro forma financial information was not presented as results were immaterial to the Company's consolidated results for the quarter ended March 23, 2019.

Revenue

Revenue	3 Months Ended
	Mar. 23, 2019
Revenue from Contract with Customer [Abstract]
Revenue	REVENUE We account for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Revenue is recognized when our performance obligations under the terms of a contract with our customers are satisfied. Recognition occurs when the Company transfers control by completing the specified services at the point in time the customer benefits from the services performed or once our products are delivered. The Company measures progress toward complete satisfaction of a performance obligation satisfied over time using a cost-based input method. This method of measuring progress provides a faithful depiction of the transfer of goods or services because the costs incurred are expected to be substantially proportionate to the Company’s satisfaction of the performance obligation. Revenue is measured as the amount of consideration we expect to receive in exchange for completing our performance obligations. Sales tax and other taxes we collect with revenue-producing activities are excluded from revenue. In the case of contracts with multiple performance obligations, the Company allocates the transaction price to each performance obligation based on the relative stand-alone selling prices of the various goods and/or services encompassed by the contract. We do not have any material significant payment terms as payment is generally due within 30 days after the performance obligation has been satisfactorily completed. The Company has elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that we otherwise would have recognized is one year or less. In applying the guidance in Topic 606, there were no judgments or estimates made that the Company deems significant. Accounts Receivable — Net, includes amounts billed and currently due from customers. The amounts due are stated at their net estimated realizable value. The allowance for doubtful accounts is the Company's best estimate of the amount of probable credit losses in the Company's existing accounts receivable. The Company determines the allowance based on analysis of customer credit worthiness and historical losses. Accounts receivable are written off once the Company determines the account to be uncollectible. The Company does not have any off-balance-sheet credit exposure related to its customers. Contract Balances — Contract assets primarily relate to the Company’s rights to consideration for work completed in relation to its services performed but not billed at the reporting date. Contract liabilities primarily consist of advance payments of performance obligations yet to be fully satisfied in the period reported. Our contract liabilities and contract assets are reported in a net position at the end of each reporting period. We disaggregate our revenue from contracts with customers by major lines of business for each of our segments, as we believe it best depicts how the nature, amount, timing and uncertainty of our revenue and cash flows are affected by economic factors. The following table disaggregates our revenue by major lines: For the First Quarter Ended, March 23, 2019 Total Net Sales by Major Lines of Business (thousands) Environmental Services Oil Business Total Parts cleaning, containerized waste, & related products/services $ 38,134 $ — $ 38,134 Vacuum Services & Wastewater Treatment 13,976 — 13,976 Antifreeze Business 6,658 — 6,658 Field Services 3,841 — 3,841 Environmental Services - Other 403 — 403 Re-refinery Product Sales — 24,035 24,035 Oil Collection Services & RFO — 3,962 3,962 Oil Filter Business — 1,215 1,215 Revenues from Contracts with Customers 63,012 29,212 92,224 Other Revenue 3,484 64 3,548 Total Revenues $ 66,496 $ 29,276 $ 95,772 The following table provides information about contract assets and contract liabilities from contracts with customers: (thousands) March 23, 2019 December 29, 2018 Contract assets $ 45 $ 100 Contract liabilities 2,444 266 Contract liabilities - net $ 2,399 $ 166 During the quarter ended March 23, 2019, the Company recognized $0.3 million of revenue that was included in the contract liabilities balance as of December 29, 2018. During the quarter ended March 23, 2019, the Company recognized within Contract liabilities - net approximately $2.2 million of deferred rental income as a result of the Company having adopted ASC 842 on December 30, 2018. The Company has no assets recognized from costs to obtain or fulfill a contract with a customer. We do not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less.

Accounts Receivable

Accounts Receivable	3 Months Ended
	Mar. 23, 2019
Accounts Receivable, Net [Abstract]
Accounts Receivable	ACCOUNTS RECEIVABLE Accounts receivable consisted of the following: (thousands) March 23, December 29, Trade $ 52,455 $ 51,118 Less: allowance for doubtful accounts 1,841 1,816 Trade - net 50,614 49,302 Related parties 2,083 1,595 Other 629 847 Total accounts receivable - net $ 53,326 $ 51,744 The following table provides the changes in the Company’s allowance for doubtful accounts for the first quarter ended March 23, 2019, and the fiscal year ended December 29, 2018: (thousands) March 23, December 29, Balance at beginning of period $ 1,816 $ 1,881 Provision for bad debts 249 628 Accounts written off, net of recoveries (224 ) (693 ) Balance at end of period $ 1,841 $ 1,816

Inventory

Inventory	3 Months Ended
	Mar. 23, 2019
Inventory Disclosure [Abstract]
Inventory	INVENTORY The carrying value of inventory consisted of the following: (thousands) March 23, December 29, Used oil and processed oil $ 8,664 $ 12,124 Solvents and solutions 7,983 8,216 Machines 5,988 5,334 Drums and supplies 5,098 5,231 Other 2,170 2,378 Total inventory 29,903 33,283 Less: machine refurbishing reserve 242 224 Total inventory - net $ 29,661 $ 33,059 Inventory consists primarily of used oil, processed oil, solvents and solutions, new and refurbished parts cleaning machines, drums and supplies, and other items. Inventories are valued at the lower of first-in, first-out (FIFO) cost or net realizable value, net of any reserves for excess, obsolete, or unsalable inventory. The Company routinely monitors its inventory levels at each of its locations and evaluates inventories for excess or slow-moving items. If circumstances indicate the cost of inventories exceed their recoverable value, inventories are reduced to net realizable value. The Company had no inventory write downs during the first quarters of fiscal 2019 or fiscal 2018.

Property, Plant, and Equipment

Property, Plant, and Equipment	3 Months Ended
	Mar. 23, 2019
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment	PROPERTY, PLANT, AND EQUIPMENT Property, plant, and equipment consisted of the following: (thousands) March 23, December 29, Machinery, vehicles, and equipment $ 100,350 $ 98,708 Buildings and storage tanks 69,977 69,791 Land 9,659 9,546 Leasehold improvements 5,738 5,701 Construction in progress 20,251 15,405 Assets held for sale 4 4 Total property, plant and equipment 205,979 199,155 Less: accumulated depreciation 61,183 59,168 Property, plant and equipment - net $ 144,796 $ 139,987 (thousands) March 23, December 29, Equipment at customers $ 74,113 $ 73,075 Less: accumulated depreciation 50,274 49,261 Equipment at customers - net $ 23,839 $ 23,814 Depreciation expense for the first quarters ended March 23, 2019 and March 24, 2018 was $3.1 million and $2.9 million , respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 23, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill is measured as a residual amount as of the acquisition date, which in most cases results in measuring goodwill as an excess of the purchase consideration transferred plus the fair value of any noncontrolling interest in the acquiree over the fair value of the net assets acquired, including any contingent consideration. The Company tests goodwill for impairment annually in the fourth quarter and in interim periods if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. The Company's determination of fair value requires certain assumptions and estimates, such as margin expectations, market conditions, growth expectations, expected changes in working capital, etc., regarding expected future profitability and expected future cash flows. The Company tests goodwill for impairment at each of its two reporting units, Environmental Services and Oil Business. The following table shows changes to our goodwill balances by segment from December 29, 2018 to March 23, 2019: (thousands) Oil Business Environmental Services Total Goodwill at December 29, 2018 Gross carrying amount $ 3,952 $ 34,123 $ 38,075 Accumulated impairment loss (3,952 ) — (3,952 ) Net book value at December 29, 2018 $ — $ 34,123 $ 34,123 Measurement period adjustments — (1,765 ) — Goodwill at March 23, 2019 Gross carrying amount 3,952 32,358 36,310 Accumulated impairment loss (3,952 ) — (3,952 ) Net book value at March 23, 2019 $ — $ 32,358 $ 32,358 The following is a summary of software and other intangible assets: March 23, 2019 December 29, 2018 (thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer & supplier relationships $ 25,020 $ 12,001 $ 13,019 $ 23,686 $ 11,445 $ 12,241 Software 6,446 4,452 1,994 5,040 4,094 946 Non-compete agreements 3,369 2,952 417 2,937 2,904 33 Patents, formulae, and licenses 1,769 723 1,046 1,769 708 1,061 Other 1,701 1,107 594 1,442 1,042 400 Total software and intangible assets - net $ 38,305 $ 21,235 $ 17,070 $ 34,874 $ 20,193 $ 14,681 Amortization expense was $1.0 million for the first quarter ended March 23, 2019, and $0.7 million for the first quarter ended March 24, 2018. The weighted average useful lives of software; customer & supplier relationships; patents, formulae, and licenses; non-compete agreements, and other intangibles were 10 years, 11 years, 15 years, 5 years, and 7 years, respectively. The expected amortization expense for the remainder of fiscal 2019 and for fiscal years 2020, 2021, 2022, and 2023 is $2.4 million , $3.0 million , $2.8 million , $2.6 million , and $2.1 million , respectively. The preceding expected amortization expense is an estimate. Actual amounts of amortization expense may differ from estimated amounts due to additional intangible asset acquisitions, the finalization of the fair value of intangible assets that have been acquired from business combinations, disposal of intangible assets, accelerated amortization of intangible assets, and other events.

Accounts Payable

Accounts Payable	3 Months Ended
	Mar. 23, 2019
Payables and Accruals [Abstract]
Accounts Payable	ACCOUNTS PAYABLE Accounts payable consisted of the following: (thousands) March 23, December 29, Accounts payable $ 34,459 $ 32,471 Accounts payable - related parties 399 159 Total accounts payable $ 34,858 $ 32,630

Debt and Financing Arrangements

Debt and Financing Arrangements	3 Months Ended
	Mar. 23, 2019
Debt Disclosure [Abstract]
Debt and Financing Arrangements	DEBT AND FINANCING ARRANGEMENTS Bank Credit Facility The Company's Credit Agreement as amended ("Credit Agreement"), provides for borrowings of up to $95.0 million , subject to the satisfaction of certain terms and conditions, comprised of a term loan of $30.0 million and up to $65.0 million of borrowings under the revolving loan portion. The actual amount of borrowings available under the revolving loan portion of the Credit Agreement is limited by the Company's total leverage ratio. The amount available to draw at any point in time would be further reduced by any standby letters of credit issued. Loans made under the Credit Agreement may be Base Rate Loans or LIBOR Rate Loans, at the election of the Company subject to certain exceptions. Base Rate Loans have an interest rate equal to (i) the higher of (a) the federal funds rate plus 0.5% , (b) the London Interbank Offering Rate (“LIBOR”) plus 1% , or (c) Bank of America's prime rate, plus (ii) a variable margin of between 0.75% and 1.75% depending on the Company's total leverage ratio, calculated on a consolidated basis. LIBOR rate loans have an interest rate equal to (i) the LIBOR rate plus (ii) a variable margin of between 1.75% and 2.75% depending on the Company's total leverage ratio. Amounts borrowed under the Credit Agreement are secured by a security interest in substantially all of the Company's tangible and intangible assets. The Credit Agreement contains customary terms and provisions (including representations, covenants, and conditions) for transactions of this type. Certain covenants, among other things, restrict the Company's and its subsidiaries' ability to incur indebtedness, grant liens, make investments and sell assets. The Credit Agreement also contains customary events of default, covenants and representations and warranties. Financial covenants include: • An interest coverage ratio (based on interest expense and EBITDA) of at least 3.5 to 1.0 ; • A total leverage ratio no greater than 3.0 to 1.0 , provided that in the event of a permitted acquisition having an aggregate consideration equal to $10.0 million or more, at the Borrower’s election, the total leverage ratio shall be deemed to be 3.25 to 1.00 for the fiscal quarter in which such permitted acquisition occurs and the three immediately following fiscal quarters and thereafter will revert to 3.00 to 1.00 ; and • A capital expenditures covenant limiting capital expenditures to $100.0 million plus, if the capital expenditures permitted have been fully utilized, an additional amount for the remaining term of the Credit Agreement equal to 35% of EBITDA for the thirteen “four-week” periods most recently ended immediately prior to the full utilization of such $100.0 million basket. The Credit Agreement places certain limitations on acquisitions and the payment of dividends. Debt at March 23, 2019 and December 29, 2018 consisted of the following: (thousands) March 23, 2019 December 29, 2018 Principal amount $ 30,000 $ 30,000 Less: unamortized debt issuance costs 884 954 Debt less unamortized debt issuance costs $ 29,116 $ 29,046 The Company recorded interest expense of $0.4 million , of which $0.3 million is on our term loan, and $0.1 million which is amortization of debt issuance costs, for the first quarter ended March 23, 2019. The Company recorded interest expense of $0.3 million for the first quarter ended March 24, 2018 which was primarily on our term loan. The Company's weighted average interest rate for all debt as of March 23, 2019, and March 24, 2018 was 4.5% and 3.4% , respectively. As of March 23, 2019 and December 29, 2018, the Company was in compliance with all covenants under its Credit Agreement. As of March 23, 2019 and December 29, 2018, the Company had $1.2 million and $1.3 million of standby letters of credit issued, respectively, and $63.8 million and $63.7 million was available for borrowing under the bank credit facility, respectively. We believe that the carrying value of our debt balance at March 23, 2019 approximates fair value.

Segment Information

Segment Information	3 Months Ended
	Mar. 23, 2019
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION The Company has two reportable segments: "Environmental Services" and "Oil Business." The Environmental Services segment consists primarily of the Company's parts cleaning, containerized waste management, vacuum truck service, antifreeze recycling activities, and field services. The Oil Business segment consists primarily of the Company's used oil collection, used oil re-refining activities, and the dehydration of used oil to be sold as recycled fuel oil. No single customer in either segment accounted for more than 10.0% of consolidated revenues in any of the periods presented. There were no intersegment revenues. Both the Environmental Services and Oil Business segment operate in the United States and, to an immaterial degree, in Ontario, Canada. As such, the Company is not disclosing operating results by geographic segment. Segment results for the first quarters ended March 23, 2019, and March 24, 2018 were as follows: First Quarter Ended, March 23, 2019 (thousands) Environmental Services Oil Business Corporate and Consolidated Revenues Service revenues $ 52,875 $ 3,491 $ — $ 56,366 Product revenues 10,137 25,721 — 35,858 Rental income 3,484 64 — 3,548 Total revenues $ 66,496 $ 29,276 $ — $ 95,772 Operating expenses Operating costs 50,163 32,320 — 82,483 Operating depreciation and amortization 1,636 1,434 — 3,070 Profit (loss) before corporate selling, general, and administrative expenses $ 14,697 $ (4,478 ) $ — $ 10,219 Selling, general, and administrative expenses 12,396 12,396 Depreciation and amortization from SG&A 1,066 1,066 Total selling, general, and administrative expenses $ 13,462 $ 13,462 Other income - net (58 ) (58) Operating loss (3,185) Interest expense – net 230 230 Loss before income taxes $ (3,415 ) First Quarter Ended, March 24, 2018 (thousands) Environmental Services Oil Business Corporate and Consolidated Revenues Service revenues $ 51,032 $ 3,105 $ — $ 54,137 Product revenues 6,444 22,566 — 29,010 Total revenues $ 57,476 $ 25,671 $ — $ 83,147 Operating expenses Operating costs 42,725 25,661 — 68,386 Operating depreciation and amortization 1,490 1,389 — 2,879 Profit (loss) before corporate selling, general, and administrative expenses $ 13,261 $ (1,379 ) $ — $ 11,882 Selling, general, and administrative expenses 11,022 11,022 Depreciation and amortization from SG&A 764 764 Total selling, general, and administrative expenses $ 11,786 $ 11,786 Other expense - net 389 389 Operating loss (293) Interest expense – net 245 245 Loss before income taxes $ (538 ) Total assets by segment as of March 23, 2019, and December 29, 2018 were as follows: (thousands) March 23, 2019 December 29, 2018 Total Assets: Environmental Services $ 197,092 $ 148,192 Oil Business 157,383 142,691 Unallocated Corporate Assets 57,110 56,939 Total $ 411,585 $ 347,822 Segment assets for the Environmental Services and Oil Business segments consist of property, plant, and equipment, right-of-use assets, intangible assets, accounts receivable, goodwill, and inventories. Assets for the corporate unallocated amounts consist of property, plant, and equipment used at the corporate headquarters as well as cash and net deferred tax assets.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 23, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES LEASES Lessee The Company leases buildings and property, railcars, machinery and equipment, and various types of vehicles for use in our operations. Each arrangement is evaluated individually to determine if the arrangement is or contains a lease at inception. The Company has lease agreements with lease and non-lease components and we have elected to not separate lease and non-lease components for all classes of underlying assets. In addition, our lease agreements do not contain any material residual guarantees or restrictive covenants. Leases may include variable lease payments for common area maintenance, real estate taxes, and truck lease mileage. No leases are tied to a market index rate or CPI. Variable lease payments are not included in the initial measurement of the right-of-use assets or lease liabilities, and are recorded as lease expense in the period incurred. Unless leases include an option to renew terms for longer than a year, leases with an initial term of 12 months or less are not recorded on our Consolidated Balance Sheet. Leases with initial terms in excess of 12 months are recorded as operating leases in our Consolidated Balance Sheet. Right-of-use assets represent the Company's right to use an underlying asset during the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. Operating lease right-of-use assets are measured at the initial measurement of the lease liability, adjusted for any lease payments made prior to the lease commencement date, less any lease incentives received and other initial direct costs incurred. Operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of our leases do not provide an implicit rate, we use an incremental borrowing rate based on the information available at commencement date, including lease term, in determining the present value of future payments. Our leases have remaining terms ranging from less than one month to 11 years and may include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the lease term. We have no finance leases as of March 23, 2019. The components of lease expense were as follows: (thousands) For the First Quarter Ended, March 23, 2019 Operating lease cost $ 6,031 Short-term lease cost 1,404 Variable lease cost 1,093 Total lease cost $ 8,528 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 6,341 Right-of-use assets obtained in exchange for new operating lease liabilities $ 67,593 As of March 23, 2019 Weighted-average remaining lease term 4.40 Weighted-average discount rate 5.5 % Future annual minimum lease payment commitments as of March 23, 2019 were as follows: (thousands) 2019 $ 16,705 2020 16,997 2021 13,355 2022 10,139 2023 6,887 2024 and thereafter 6,822 Total minimum lease payments $ 70,905 Less: imputed interest 8,174 Lease liability $ 62,731 Lessor The Company is a lessor of portions of a building and property, railcars, and equipment such as embedded leases of parts cleaning machines. Each of the Company’s leases is classified as an operating lease, and the vast majority are short-term leases. Variable lease payments include real and personal property taxes, which are based on the lessee’s pro rata portion of such amounts, and excess mileage charges which are computed as the actual miles traveled in a calendar year minus the maximum average mileage allowance as specified per the contract. Options to extend the lease beyond the original terms range from day-to-day renewals to increments of five -year extensions. Options to terminate the lease range from immediate termination upon return of the asset to various written notification periods following a minimum lease term. Options for a lessee to purchase the underlying asset are not contractually specified but may be negotiated on a case-by-case basis. Significant judgments made in determining whether a contract contains a lease include assessments as to whether or not the contract conveys the right to direct the use of an identified asset. Significant judgments made in allocating consideration between lease and non-lease components include techniques applied in estimating the relative stand-alone selling prices of the lease and non-lease components of the contract in cases where a stand-alone selling price is not directly observable. As of March 23, 2019, the Company is party to a contract under which it leases railcars to the related party Calumet Specialty Products Partners, L.P. No leased assets are covered by residual value guarantees. The Company manages the risk associated with the residual value of leased assets through such means as performing periodic maintenance and upkeep activities and the inclusion of contractual terms that hold the lessee responsible for damage incurred to leased assets. Contained in Note 7, “Property, plant, and equipment,” are disclosures concerning the Company’s underlying assets under operating leases. The Company has made an accounting policy election to exclude from the consideration in the contract and from variable payments not included in the consideration in the contract all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific lease revenue-producing transaction and collected by the lessor from a lessee. The Company recognizes rental income on a straight-line basis for that portion of the consideration allocated to the embedded lease component of certain of our parts cleaning contracts. We also recognize rental income on certain subleases of railcars and portions of a building and property. Rental income for the first quarter ended March 23, 2019 was as follows: (thousands) Environmental Services Oil Business Total Parts Cleaning $ 3,484 $ — $ 3,484 Railcars — 57 57 Property — 7 7 Total rental income $ 3,484 $ 64 $ 3,548 Purchase Obligations The Company may enter into purchase obligations with certain vendors. They represent expected payments to third party service providers and other commitments entered into during the normal course of our business. These purchase obligations are generally cancelable with or without notice, without penalty, although certain vendor agreements provide for cancellation fees or penalties depending on the terms of the contract. The Company has purchase obligations in the form of open purchase orders of $19.0 million as of March 23, 2019, and $18.6 million as of December 29, 2018, primarily for used oil, solvent, machine purchases, disposal and transportation expenses, and capital expenditures. The Company may be subject to investigations, claims or lawsuits as a result of operating its business, including matters governed by environmental laws and regulations. The Company may also be subject to tax audits in a variety of jurisdictions. When claims are asserted, the Company evaluates the likelihood that a loss will occur and records a liability for those instances when the likelihood is deemed probable and the exposure is reasonably estimable. The Company carries insurance at levels it believes are adequate to cover loss contingencies based on historical claims activity. When the potential loss exposure is limited to the insurance deductible and the likelihood of loss is determined to be probable, the Company accrues for the amount of the required deductible, unless a lower amount of exposure is estimated. As of March 23, 2019 and December 29, 2018, the Company had accrued $4.4 million and $4.2 million related to loss contingencies and other contingent liabilities, respectively.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 23, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The Company deducted for federal income tax purposes accelerated "bonus" depreciation on the majority of its capital expenditures for assets placed in service in fiscal 2011 through the first quarter of 2019. Therefore, the Company recorded a noncurrent deferred tax liability as to the difference between the book basis and the tax basis of those assets. In addition, as a result of the federal bonus depreciation, the Company recorded a Net Operating Loss ("NOL"). The balance on the federal NOL as of March 23 rd , 2019 was $26.2 million . There are also state NOLs of varying amounts, dependent on each state’s conformity with bonus depreciation. The remaining deferred tax asset related to the Company's state and federal NOL was a tax effected balance of $5.9 million . The Company's effective tax rate for the first quarter of fiscal 2019 was 28.9% compared to 81.1% in the first quarter of fiscal 2018. The rate difference is principally attributable to windfall tax benefits associated with stock compensation having a lesser effect on the tax rate compared to the first quarter of 2018. The Company establishes reserves when it is more likely than not that the Company will not realize the full tax benefit of a position. The Company had a reserve of $2.5 million for uncertain tax positions as of March 23, 2019. The gross unrecognized tax benefits would, if recognized, decrease the Company's effective tax rate.

Share-based Compensation

Share-based Compensation	3 Months Ended
	Mar. 23, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation	SHARE-BASED COMPENSATION On February 20, 2019, the Compensation Committee and the Board of Directors of the Company adopted the 2019 Incentive Award Plan (the “2019 Plan”), to replace the Company’s 2008 Omnibus Incentive Plan (“2008 Plan”), which expired in March 2018. The 2019 Plan is subject to shareholder approval, and if the stockholders approve the 2019 Plan, the total number of shares of common stock that will be made available for award grants under the 2019 Plan will be 1,500,000 shares. Stock Option Awards A summary of stock option activity under this Plan is as follows: Outstanding Stock Options Number of Options Outstanding Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value as of Date Listed (in thousands) Options outstanding at December 29, 2018 2,760 $ 7.33 0.24 $ 41 Exercised (2,760 ) 7.33 — — Options outstanding at March 23, 2019 — $ — — $ — Restricted Stock Compensation/Awards Annually, the Company grants restricted shares to its Board of Directors. The shares become fully vested one year from their grant date. The fair value of each restricted stock grant is based on the closing price of the Company's common stock on the date of grant. The Company amortizes the expense over the service period, which is the fiscal year in which the award is granted. In addition, the Company may grant restricted shares to certain members of management based on their services and contingent upon continued service with the Company. The restricted shares vest over a period of approximately three years from the grant date. The fair value of each restricted stock grant is based on the closing price of the Company's common stock on the date of grant. The following table shows a summary of restricted share grants and expense resulting from the awards: Compensation Expense (thousands, except share amounts) First Quarters Ended, Unrecognized Expense as of, Recipient of Grant Grant Date Restricted Shares March 23, 2019 March 24, 2018 March 23, 2019 December 29, 2018 Members of Management February, 2017 146,564 $ 89 $ 99 $ 296 $ 385 Chief Executive Officer February, 2017 500,000 205 511 1,025 1,230 Members of Management February, 2018 116,958 136 122 1,040 1,176 Members of Management April, 2018 350,000 163 — 5,192 6,633 Board of Directors May, 2018 13,800 — 66 — — In February 2017, as part of Mr. Recatto's employment agreement, the Company granted a restricted stock award of 500,000 shares of common stock, which vests through January 2021 in an amount based on the vesting table below, with the common stock price increase to be determined based on the increase in the price of the Company’s common stock (if any) from the closing price of the common stock as reported by Nasdaq on the employment commencement date ( $15.00 ) and the common stock price on the potential vesting date (determined by using the weighted average closing price of a share of the Company's common stock for the 90-day period ending on the vesting date). If the stock price does not increase by $5.00 , then no shares shall vest. During the first quarter of fiscal 2019, the Company recorded approximately $0.2 million of compensation expense related to this award. In the future, the Company expects to recognize compensation expense of approximately $1.0 million over the remaining requisite service period, which ends January 31, 2021. The fair value of this restricted stock award as of the grant date was estimated using a Monte Carlo simulation model. Key assumptions used in the Monte Carlo simulation to estimate the grant date fair value of this award are a risk-free rate of 1.70% , expected dividend yield of zero , and an expected volatility assumption of 41.73% . Vesting Table Increase in Stock Price From the Employment Commencement Date to the Vesting Date Total percentage of Restricted Stock Shares to Be Vested Less than $5 per share increase —% $5 per share increase 25% $10 per share increase 50% $15 per share increase 75% $20 or more per share increase 100% Provision for possible accelerated vesting of award If the average closing price of the Company's common stock increases by the marginal levels set forth in the above vesting table for any consecutive 180 day period between the award date and final vesting date, Mr. Recatto shall become vested in 50% of the corresponding total percentage of restricted shares earned on the last day of the 180 day period. On March 14, 2018, the average closing price of the Company's common stock met the 25% marginal level and Mr. Recatto became fully vested in half of the 125,000 vested shares. The following table summarizes the restricted stock activity for the first quarter ended March 23, 2019: Restricted Stock (Nonvested Shares) Number of Shares Weighted Average Grant-Date Fair Value Per Share Nonvested shares outstanding at December 29, 2018 1,013,863 $ 18.20 Granted — — Vested (82,072 ) 16.99 Forfeited (65,641 ) 22.04 Nonvested shares outstanding at March 23, 2019 866,150 $ 18.02 Employee Stock Purchase Plan As of March 23, 2019, the Company had reserved 124,287 shares of common stock available for purchase under the Employee Stock Purchase Plan. In the first quarter of fiscal 2019, employees purchased 4,975 shares of the Company’s common stock with a weighted average fair market value of $23.54 per share.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 23, 2019
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The following table reconciles the number of shares outstanding for the first quarters of fiscal 2019 and 2018, respectively, to the number of weighted average basic shares outstanding and the number of weighted average diluted shares outstanding for the purposes of calculating basic and diluted earnings per share: First Quarter Ended, (thousands, except share amounts) March 23, 2019 March 24, 2018 Net loss $ (2,429 ) $ (102 ) Less: income attributable to noncontrolling interest 83 18 Net loss attributable to Heritage-Crystal Clean, Inc. available to common stockholders $ (2,512 ) $ (120 ) Weighted average basic shares outstanding 23,117 22,962 Weighted average diluted shares outstanding 23,117 22,962 Number of anti–dilutive potentially issuable shares excluded from diluted shares outstanding 248 170 Net loss per share: basic $ (0.11 ) $ (0.01 ) Net loss per share: diluted $ (0.11 ) $ (0.01 )

Other (Income) Expense - Net

Other (Income) Expense - Net	3 Months Ended
	Mar. 23, 2019
Other Income and Expenses [Abstract]
Other (Income) Expense - Net	OTHER (INCOME) EXPENSE - NET Other (income) expense - net was $0.1 million of income for the first quarter of fiscal 2019. Other expense (income) - net of $0.4 million of expense for the first quarter of fiscal 2018 primarily related to $0.3 million of site closure costs for a facility in Wilmington, DE.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 23, 2019
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS On February 20, 2019, the Compensation Committee and the Board of Directors of the Company adopted the 2019 Incentive Award Plan (the “2019 Plan”). The 2019 plan was approved by shareholders on May 1, 2019 at the Company's Annual Meeting. See footnote 14 — Share-Based Compensation for more information. On March 25, 2019, the Company completed the acquisition of certain assets of All Valley Disposal, Inc., an environmental services provider based in Fresno, California. Consideration for the acquisition paid at closing was approximately $0.6 million . Contingent upon the achievement of certain business performance metrics, total consideration for the acquisition could reach a maximum of approximately $1.3 million .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 23, 2019
Accounting Policies [Abstract]
Fiscal Period	The Company’s fiscal year ends on the Saturday closest to December 31. The most recent fiscal year ended on December 29, 2018. Each of the Company's first three fiscal quarters consists of twelve weeks while the last fiscal quarter consists of sixteen or seventeen weeks.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Standard Issuance Date Description Our Effective Date Effect on the Financial Statements ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” June 2016 This update modifies the impairment model for most financial assets and certain other instruments. For trade and other receivables, held-to-maturity debt securities, loans and other instruments, entities will be required to utilize a new forward-looking “expected loss” methodology that generally will result in the earlier recognition of allowance for losses. December 29, 2019 The Company is evaluating the impact this new standard would have on our consolidated financial statements. Recently Issued Accounting Standards Adopted Standard Issuance Date Description Effective Date Effect on the Financial Statements ASU 2016-02 February 2016 This update was issued to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Early application of the amendments in this update is permitted for all entities. December 30, 2018 The Company adopted the new leasing standard ASC 842 "Leases" on December 30, 2018. ASU 2016-02 provides for a modified retrospective transition approach requiring lessees to recognize and measure leases on the balance sheet at the beginning of either the earliest period presented or as of the beginning of the period of adoption. The Company elected to apply ASU 2016-02 as of the beginning of the period of adoption (December 30, 2018) and will not restate comparative periods. The adoption resulted in the recognition of $63.3 million of right of use assets and $63.3 million of lease liabilities. The Company recognized approximately $2.2 million of deferred rental income from certain embedded leases during the first quarter of 2019.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - (Tables)	3 Months Ended
	Mar. 23, 2019
Accounting Policies [Abstract]
Schedule of Cumulative Effects of Changes	Effective December 30, 2018, the Company adopted the requirements of Topic 842. The cumulative effects of the changes made to our Statement of Income and Balance Sheet are as follows: For the First Quarter Ended, March 23, 2019 As Reported Balances Without Adoption of Topic 842 Effect of Change (thousands) Higher/(Lower) Statement of Income Service revenues $ 56,366 $ 62,116 $ (5,750 ) Rental income 3,548 — 3,548 Total revenues 95,772 97,974 (2,202 ) Operating loss (3,185 ) (983 ) (2,202 ) Loss before income taxes (3,415 ) (1,213 ) (2,202 ) Net loss (2,429 ) (862 ) (1,567 ) Net loss attributable to Heritage-Crystal Clean, Inc. common stockholders $ (2,512 ) $ (945 ) $ (1,567 ) Net loss per share: basic $ (0.11 ) $ (0.04 ) $ (0.07 ) Net loss per share: diluted $ (0.11 ) $ (0.04 ) $ (0.07 ) March 23, 2019 As Reported Balances Without Adoption of Topic 842 Effect of Change (thousands) Higher/(Lower) Balance Sheet Right of use assets $ 62,929 $ — $ 62,929 Total assets 411,585 348,656 62,929 Current portion of lease liabilities 18,433 — 18,433 Contract liabilities - net 2,399 197 2,202 Other current liabilities 5,986 5,788 198 Total current liabilities 72,449 51,616 20,833 Lease liabilities, net of current portion 44,298 — 44,298 Deferred income taxes 13,544 14,179 (635 ) Total liabilities 159,407 94,911 64,496 Retained earnings 53,307 54,874 (1,567 ) Heritage-Crystal Clean, Inc. stockholders' equity $ 251,447 $ 253,014 $ (1,567 ) Total equity $ 252,178 $ 253,745 $ (1,567 ) Total liabilities and stockholders' equity $ 411,585 $ 348,656 $ 62,929

Business Combinations (Tables)

Business Combinations (Tables)	3 Months Ended
	Mar. 23, 2019
Business Combinations [Abstract]
Schedule of Estimated Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair values of the assets acquired, some of which are preliminary, related to each acquisition: As of March 23, 2019 (thousands) GlyEco WSS PPI HTSC Accounts receivable $ 359 $ — $ 909 $ 40 Inventory 290 28 259 3 Property, plant, & equipment 746 154 2,154 47 Equipment at customers — 24 — 104 Intangible assets 251 298 2,001 100 Goodwill — — 406 377 Total purchase price, net of cash acquired $ 1,646 $ 504 $ 5,729 $ 671 Less: working capital adjustment 23 14 (62 ) (9 ) Less: deferred consideration — — — 225 Less: contingent consideration — 90 1,341 100 Less: to be placed in escrow — 50 — — Net cash paid $ 1,623 $ 350 $ 4,450 $ 355

Revenue (Tables)

Revenue (Tables)	3 Months Ended
	Mar. 23, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue by Major Lines	The following table disaggregates our revenue by major lines: For the First Quarter Ended, March 23, 2019 Total Net Sales by Major Lines of Business (thousands) Environmental Services Oil Business Total Parts cleaning, containerized waste, & related products/services $ 38,134 $ — $ 38,134 Vacuum Services & Wastewater Treatment 13,976 — 13,976 Antifreeze Business 6,658 — 6,658 Field Services 3,841 — 3,841 Environmental Services - Other 403 — 403 Re-refinery Product Sales — 24,035 24,035 Oil Collection Services & RFO — 3,962 3,962 Oil Filter Business — 1,215 1,215 Revenues from Contracts with Customers 63,012 29,212 92,224 Other Revenue 3,484 64 3,548 Total Revenues $ 66,496 $ 29,276 $ 95,772
Contract Assets and Contract Liabilities from Contracts with Customers	The following table provides information about contract assets and contract liabilities from contracts with customers: (thousands) March 23, 2019 December 29, 2018 Contract assets $ 45 $ 100 Contract liabilities 2,444 266 Contract liabilities - net $ 2,399 $ 166

Accounts Receivable (Tables)

Accounts Receivable (Tables)	3 Months Ended
	Mar. 23, 2019
Accounts Receivable, Net [Abstract]
Schedule of Accounts Receivable and Allowance for Doubtful Accounts	Accounts receivable consisted of the following: (thousands) March 23, December 29, Trade $ 52,455 $ 51,118 Less: allowance for doubtful accounts 1,841 1,816 Trade - net 50,614 49,302 Related parties 2,083 1,595 Other 629 847 Total accounts receivable - net $ 53,326 $ 51,744 The following table provides the changes in the Company’s allowance for doubtful accounts for the first quarter ended March 23, 2019, and the fiscal year ended December 29, 2018: (thousands) March 23, December 29, Balance at beginning of period $ 1,816 $ 1,881 Provision for bad debts 249 628 Accounts written off, net of recoveries (224 ) (693 ) Balance at end of period $ 1,841 $ 1,816

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Mar. 23, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory	The carrying value of inventory consisted of the following: (thousands) March 23, December 29, Used oil and processed oil $ 8,664 $ 12,124 Solvents and solutions 7,983 8,216 Machines 5,988 5,334 Drums and supplies 5,098 5,231 Other 2,170 2,378 Total inventory 29,903 33,283 Less: machine refurbishing reserve 242 224 Total inventory - net $ 29,661 $ 33,059

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	3 Months Ended
	Mar. 23, 2019
Property, Plant and Equipment [Abstract]
Summary of Property, Plant, and Equipment	Property, plant, and equipment consisted of the following: (thousands) March 23, December 29, Machinery, vehicles, and equipment $ 100,350 $ 98,708 Buildings and storage tanks 69,977 69,791 Land 9,659 9,546 Leasehold improvements 5,738 5,701 Construction in progress 20,251 15,405 Assets held for sale 4 4 Total property, plant and equipment 205,979 199,155 Less: accumulated depreciation 61,183 59,168 Property, plant and equipment - net $ 144,796 $ 139,987 (thousands) March 23, December 29, Equipment at customers $ 74,113 $ 73,075 Less: accumulated depreciation 50,274 49,261 Equipment at customers - net $ 23,839 $ 23,814

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 23, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table shows changes to our goodwill balances by segment from December 29, 2018 to March 23, 2019: (thousands) Oil Business Environmental Services Total Goodwill at December 29, 2018 Gross carrying amount $ 3,952 $ 34,123 $ 38,075 Accumulated impairment loss (3,952 ) — (3,952 ) Net book value at December 29, 2018 $ — $ 34,123 $ 34,123 Measurement period adjustments — (1,765 ) — Goodwill at March 23, 2019 Gross carrying amount 3,952 32,358 36,310 Accumulated impairment loss (3,952 ) — (3,952 ) Net book value at March 23, 2019 $ — $ 32,358 $ 32,358
Schedule of Intangible Assets	The following is a summary of software and other intangible assets: March 23, 2019 December 29, 2018 (thousands) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer & supplier relationships $ 25,020 $ 12,001 $ 13,019 $ 23,686 $ 11,445 $ 12,241 Software 6,446 4,452 1,994 5,040 4,094 946 Non-compete agreements 3,369 2,952 417 2,937 2,904 33 Patents, formulae, and licenses 1,769 723 1,046 1,769 708 1,061 Other 1,701 1,107 594 1,442 1,042 400 Total software and intangible assets - net $ 38,305 $ 21,235 $ 17,070 $ 34,874 $ 20,193 $ 14,681

Accounts Payable (Tables)

Accounts Payable (Tables)	3 Months Ended
	Mar. 23, 2019
Payables and Accruals [Abstract]
Schedule of Accounts Payable	Accounts payable consisted of the following: (thousands) March 23, December 29, Accounts payable $ 34,459 $ 32,471 Accounts payable - related parties 399 159 Total accounts payable $ 34,858 $ 32,630

Debt and Financing Arrangemen_2

Debt and Financing Arrangements (Tables)	3 Months Ended
	Mar. 23, 2019
Debt Disclosure [Abstract]
Schedule of Debt	Debt at March 23, 2019 and December 29, 2018 consisted of the following: (thousands) March 23, 2019 December 29, 2018 Principal amount $ 30,000 $ 30,000 Less: unamortized debt issuance costs 884 954 Debt less unamortized debt issuance costs $ 29,116 $ 29,046

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 23, 2019
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Segment results for the first quarters ended March 23, 2019, and March 24, 2018 were as follows: First Quarter Ended, March 23, 2019 (thousands) Environmental Services Oil Business Corporate and Consolidated Revenues Service revenues $ 52,875 $ 3,491 $ — $ 56,366 Product revenues 10,137 25,721 — 35,858 Rental income 3,484 64 — 3,548 Total revenues $ 66,496 $ 29,276 $ — $ 95,772 Operating expenses Operating costs 50,163 32,320 — 82,483 Operating depreciation and amortization 1,636 1,434 — 3,070 Profit (loss) before corporate selling, general, and administrative expenses $ 14,697 $ (4,478 ) $ — $ 10,219 Selling, general, and administrative expenses 12,396 12,396 Depreciation and amortization from SG&A 1,066 1,066 Total selling, general, and administrative expenses $ 13,462 $ 13,462 Other income - net (58 ) (58) Operating loss (3,185) Interest expense – net 230 230 Loss before income taxes $ (3,415 ) First Quarter Ended, March 24, 2018 (thousands) Environmental Services Oil Business Corporate and Consolidated Revenues Service revenues $ 51,032 $ 3,105 $ — $ 54,137 Product revenues 6,444 22,566 — 29,010 Total revenues $ 57,476 $ 25,671 $ — $ 83,147 Operating expenses Operating costs 42,725 25,661 — 68,386 Operating depreciation and amortization 1,490 1,389 — 2,879 Profit (loss) before corporate selling, general, and administrative expenses $ 13,261 $ (1,379 ) $ — $ 11,882 Selling, general, and administrative expenses 11,022 11,022 Depreciation and amortization from SG&A 764 764 Total selling, general, and administrative expenses $ 11,786 $ 11,786 Other expense - net 389 389 Operating loss (293) Interest expense – net 245 245 Loss before income taxes $ (538 )
Reconciliation of Assets from Segment to Consolidated	Total assets by segment as of March 23, 2019, and December 29, 2018 were as follows: (thousands) March 23, 2019 December 29, 2018 Total Assets: Environmental Services $ 197,092 $ 148,192 Oil Business 157,383 142,691 Unallocated Corporate Assets 57,110 56,939 Total $ 411,585 $ 347,822

Commitments and Contingencies -

Commitments and Contingencies - (Tables)	3 Months Ended
	Mar. 23, 2019
Commitments and Contingencies Disclosure [Abstract]
Components of Lease Expense	The components of lease expense were as follows: (thousands) For the First Quarter Ended, March 23, 2019 Operating lease cost $ 6,031 Short-term lease cost 1,404 Variable lease cost 1,093 Total lease cost $ 8,528 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 6,341 Right-of-use assets obtained in exchange for new operating lease liabilities $ 67,593 As of March 23, 2019 Weighted-average remaining lease term 4.40 Weighted-average discount rate 5.5 %
Future Annual Minimum Lease Payment Commitments	Future annual minimum lease payment commitments as of March 23, 2019 were as follows: (thousands) 2019 $ 16,705 2020 16,997 2021 13,355 2022 10,139 2023 6,887 2024 and thereafter 6,822 Total minimum lease payments $ 70,905 Less: imputed interest 8,174 Lease liability $ 62,731
Rental Income	Rental income for the first quarter ended March 23, 2019 was as follows: (thousands) Environmental Services Oil Business Total Parts Cleaning $ 3,484 $ — $ 3,484 Railcars — 57 57 Property — 7 7 Total rental income $ 3,484 $ 64 $ 3,548

Share-based Compensation (Table

Share-based Compensation (Tables)	3 Months Ended
	Mar. 23, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock Option Activity	A summary of stock option activity under this Plan is as follows: Outstanding Stock Options Number of Options Outstanding Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value as of Date Listed (in thousands) Options outstanding at December 29, 2018 2,760 $ 7.33 0.24 $ 41 Exercised (2,760 ) 7.33 — — Options outstanding at March 23, 2019 — $ — — $ —
Schedule of Restricted Stock Unit Activity	The following table shows a summary of restricted share grants and expense resulting from the awards: Compensation Expense (thousands, except share amounts) First Quarters Ended, Unrecognized Expense as of, Recipient of Grant Grant Date Restricted Shares March 23, 2019 March 24, 2018 March 23, 2019 December 29, 2018 Members of Management February, 2017 146,564 $ 89 $ 99 $ 296 $ 385 Chief Executive Officer February, 2017 500,000 205 511 1,025 1,230 Members of Management February, 2018 116,958 136 122 1,040 1,176 Members of Management April, 2018 350,000 163 — 5,192 6,633 Board of Directors May, 2018 13,800 — 66 — — The following table summarizes the restricted stock activity for the first quarter ended March 23, 2019: Restricted Stock (Nonvested Shares) Number of Shares Weighted Average Grant-Date Fair Value Per Share Nonvested shares outstanding at December 29, 2018 1,013,863 $ 18.20 Granted — — Vested (82,072 ) 16.99 Forfeited (65,641 ) 22.04 Nonvested shares outstanding at March 23, 2019 866,150 $ 18.02
Schedule of Restricted Stock Vesting Percentages	Vesting Table Increase in Stock Price From the Employment Commencement Date to the Vesting Date Total percentage of Restricted Stock Shares to Be Vested Less than $5 per share increase —% $5 per share increase 25% $10 per share increase 50% $15 per share increase 75% $20 or more per share increase 100%

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 23, 2019
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	The following table reconciles the number of shares outstanding for the first quarters of fiscal 2019 and 2018, respectively, to the number of weighted average basic shares outstanding and the number of weighted average diluted shares outstanding for the purposes of calculating basic and diluted earnings per share: First Quarter Ended, (thousands, except share amounts) March 23, 2019 March 24, 2018 Net loss $ (2,429 ) $ (102 ) Less: income attributable to noncontrolling interest 83 18 Net loss attributable to Heritage-Crystal Clean, Inc. available to common stockholders $ (2,512 ) $ (120 ) Weighted average basic shares outstanding 23,117 22,962 Weighted average diluted shares outstanding 23,117 22,962 Number of anti–dilutive potentially issuable shares excluded from diluted shares outstanding 248 170 Net loss per share: basic $ (0.11 ) $ (0.01 ) Net loss per share: diluted $ (0.11 ) $ (0.01 )

Organization and Nature of Op_2

Organization and Nature of Operations (Details)	3 Months Ended
	Mar. 23, 2019segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	2

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Recently Issued Accounting Standards Adopted (Details) - USD ($) $ in Thousands	Dec. 30, 2018	Mar. 23, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets		$ 62,929
Lease liabilities		62,731
Deferred rental income		300
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets	$ 63,300	$ 62,929
Lease liabilities	63,300
Deferred rental income	$ 2,200

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Cumulative Effects of Changes (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 30, 2018	Dec. 29, 2018	Dec. 30, 2017
Statement of Income
Revenues	$ 95,772	$ 83,147
Rental income	3,548	0
Operating loss	(3,185)	(293)
Loss before income taxes	(3,415)	(538)
Net loss	(2,429)	(102)
Net income attributable to Heritage-Crystal Clean, Inc. available to common stockholders	$ (2,512)	$ (120)
Net loss per share: basic (in dollars per share)	$ (0.11)	$ (0.01)
Net loss per share: diluted (in dollars per share)	$ (0.11)	$ (0.01)
Balance Sheet
Right of use assets	$ 62,929
Total assets	411,585			$ 347,822
Current portion of lease liabilities	18,433
Contract liabilities - net	2,399			166
Other Liabilities, Current	5,986			5,089
Total current liabilities	72,449			50,029
Lease liabilities, net of current portion	44,298
Deferred income taxes	13,544			14,516
Total liabilities	159,407			93,591
Retained earnings	53,307			55,819
Total Heritage-Crystal Clean, Inc. stockholders' equity	251,447			253,583
Total equity	252,178	$ 235,453		254,231	$ 235,926
Total liabilities and stockholders' equity	411,585			$ 347,822
Service revenues
Statement of Income
Revenues	56,366	$ 54,137
ASU 2016-02
Statement of Income
Revenues	(2,202)
Rental income	3,548
Operating loss	(2,202)
Loss before income taxes	(2,202)
Net loss	(1,567)
Net income attributable to Heritage-Crystal Clean, Inc. available to common stockholders	$ (1,567)
Net loss per share: basic (in dollars per share)	$ (0.07)
Net loss per share: diluted (in dollars per share)	$ (0.07)
Balance Sheet
Right of use assets	$ 62,929		$ 63,300
Total assets	62,929
Current portion of lease liabilities	18,433
Contract liabilities - net	2,202
Other Liabilities, Current	198
Total current liabilities	20,833
Lease liabilities, net of current portion	44,298
Deferred income taxes	(635)
Total liabilities	64,496
Retained earnings	(1,567)
Total Heritage-Crystal Clean, Inc. stockholders' equity	(1,567)
Total equity	(1,567)
Total liabilities and stockholders' equity	62,929
ASU 2016-02 | Service revenues
Statement of Income
Revenues	(5,750)
Balances Without Adoption of Topic 842
Statement of Income
Revenues	97,974
Rental income	0
Operating loss	(983)
Loss before income taxes	(1,213)
Net loss	(862)
Net income attributable to Heritage-Crystal Clean, Inc. available to common stockholders	$ (945)
Net loss per share: basic (in dollars per share)	$ (0.04)
Net loss per share: diluted (in dollars per share)	$ (0.04)
Balance Sheet
Right of use assets	$ 0
Total assets	348,656
Current portion of lease liabilities	0
Contract liabilities - net	197
Other Liabilities, Current	5,788
Total current liabilities	51,616
Lease liabilities, net of current portion	0
Deferred income taxes	14,179
Total liabilities	94,911
Retained earnings	54,874
Total Heritage-Crystal Clean, Inc. stockholders' equity	253,014
Total equity	253,745
Total liabilities and stockholders' equity	348,656
Balances Without Adoption of Topic 842 | Service revenues
Statement of Income
Revenues	$ 62,116

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($)	Feb. 01, 2019	Jan. 11, 2019	Jun. 11, 2018	May 03, 2018	Mar. 23, 2019	May 03, 2019
GlyEco
Business Acquisition [Line Items]
Purchase price		$ 1,600,000
Less: contingent consideration					$ 0
WSS
Business Acquisition [Line Items]
Purchase price	$ 500,000
Less: contingent consideration					90,000
PPI
Business Acquisition [Line Items]
Purchase price				$ 5,900,000
Increase to property, plant, & equipment					200,000
Increase to other intangible assets					1,500,000
Decrease to contingent consideration					100,000
Decrease to goodwill					1,800,000
Performance metrics period				3 years
Minimum contingent consideration					0
Maximum contingent consideration					1,500,000
Less: contingent consideration					1,341,000
HTSC
Business Acquisition [Line Items]
Purchase price			$ 700,000
Less: contingent consideration					$ 100,000
Estimate | HTSC
Business Acquisition [Line Items]
Less: contingent consideration						$ 100,000

Business Combinations - Assets

Business Combinations - Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Business Acquisition [Line Items]
Goodwill	$ 32,358		$ 34,123
Net cash paid	1,973	$ 0
GlyEco
Business Acquisition [Line Items]
Accounts receivable	359
Inventory	290
Property, plant, & equipment	746
Equipment at customers	0
Intangible assets	251
Goodwill	0
Total purchase price, net of cash acquired	1,646
Less: working capital adjustment	23
Less: deferred consideration	0
Less: contingent consideration	0
Less: to be placed in escrow	0
Net cash paid	1,623
WSS
Business Acquisition [Line Items]
Accounts receivable	0
Inventory	28
Property, plant, & equipment	154
Equipment at customers	24
Intangible assets	298
Goodwill	0
Total purchase price, net of cash acquired	504
Less: working capital adjustment	14
Less: deferred consideration	0
Less: contingent consideration	90
Less: to be placed in escrow	50
Net cash paid	350
PPI
Business Acquisition [Line Items]
Accounts receivable	909
Inventory	259
Property, plant, & equipment	2,154
Equipment at customers	0
Intangible assets	2,001
Goodwill	406
Total purchase price, net of cash acquired	5,729
Less: working capital adjustment	(62)
Less: deferred consideration	0
Less: contingent consideration	1,341
Less: to be placed in escrow	0
Net cash paid	4,450
HTSC
Business Acquisition [Line Items]
Accounts receivable	40
Inventory	3
Property, plant, & equipment	47
Equipment at customers	104
Intangible assets	100
Goodwill	377
Total purchase price, net of cash acquired	671
Less: working capital adjustment	(9)
Less: deferred consideration	225
Less: contingent consideration	100
Less: to be placed in escrow	0
Net cash paid	$ 355

Revenue - Schedule of Disaggreg

Revenue - Schedule of Disaggregation of Revenue by Major Lines (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018
Revenue from Contract with Customer [Abstract]
Performance obligation timing	We do not have any material significant payment terms as payment is generally due within 30 days after the performance obligation has been satisfactorily completed. The Company has elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that we otherwise would have recognized is one year or less.
Disaggregation of Revenue [Line Items]
Revenues	$ 92,224
Other Revenue	3,548
Total revenues	95,772	$ 83,147
Parts cleaning, containerized waste, & related products/services
Disaggregation of Revenue [Line Items]
Revenues	38,134
Vacuum Services & Wastewater Treatment
Disaggregation of Revenue [Line Items]
Revenues	13,976
Antifreeze Business
Disaggregation of Revenue [Line Items]
Revenues	6,658
Field Services
Disaggregation of Revenue [Line Items]
Revenues	3,841
Environmental Services - Other
Disaggregation of Revenue [Line Items]
Revenues	403
Re-refinery Product Sales
Disaggregation of Revenue [Line Items]
Revenues	24,035
Oil Collection Services & RFO
Disaggregation of Revenue [Line Items]
Revenues	3,962
Oil Filter Business
Disaggregation of Revenue [Line Items]
Revenues	1,215
Environmental Services
Disaggregation of Revenue [Line Items]
Revenues	63,012
Other Revenue	3,484
Total revenues	66,496
Environmental Services | Parts cleaning, containerized waste, & related products/services
Disaggregation of Revenue [Line Items]
Revenues	38,134
Environmental Services | Vacuum Services & Wastewater Treatment
Disaggregation of Revenue [Line Items]
Revenues	13,976
Environmental Services | Antifreeze Business
Disaggregation of Revenue [Line Items]
Revenues	6,658
Environmental Services | Field Services
Disaggregation of Revenue [Line Items]
Revenues	3,841
Environmental Services | Environmental Services - Other
Disaggregation of Revenue [Line Items]
Revenues	403
Environmental Services | Re-refinery Product Sales
Disaggregation of Revenue [Line Items]
Revenues	0
Environmental Services | Oil Collection Services & RFO
Disaggregation of Revenue [Line Items]
Revenues	0
Environmental Services | Oil Filter Business
Disaggregation of Revenue [Line Items]
Revenues	0
Oil Business
Disaggregation of Revenue [Line Items]
Revenues	29,212
Other Revenue	64
Total revenues	29,276
Oil Business | Parts cleaning, containerized waste, & related products/services
Disaggregation of Revenue [Line Items]
Revenues	0
Oil Business | Vacuum Services & Wastewater Treatment
Disaggregation of Revenue [Line Items]
Revenues	0
Oil Business | Antifreeze Business
Disaggregation of Revenue [Line Items]
Revenues	0
Oil Business | Field Services
Disaggregation of Revenue [Line Items]
Revenues	0
Oil Business | Environmental Services - Other
Disaggregation of Revenue [Line Items]
Revenues	0
Oil Business | Re-refinery Product Sales
Disaggregation of Revenue [Line Items]
Revenues	24,035
Oil Business | Oil Collection Services & RFO
Disaggregation of Revenue [Line Items]
Revenues	3,962
Oil Business | Oil Filter Business
Disaggregation of Revenue [Line Items]
Revenues	$ 1,215

Revenue - Contract Assets and C

Revenue - Contract Assets and Contract Liabilities from Contracts with Customers (Details) - USD ($) $ in Thousands	Dec. 30, 2018	Mar. 23, 2019	Dec. 29, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract assets		$ 45	$ 100
Contract liabilities		2,444	266
Contract liabilities - net		2,399	$ 166
Deferred rental income		$ 300
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred rental income	$ 2,200
ASU 2016-02 | Rental Income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred rental income	$ 2,200

Accounts Receivable - Component

Accounts Receivable - Components of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 23, 2019	Dec. 29, 2018	Dec. 30, 2017
Accounts Receivable, Net [Abstract]
Trade	$ 52,455	$ 51,118
Less: allowance for doubtful accounts	1,841	1,816	$ 1,881
Trade - net	50,614	49,302
Related parties	2,083	1,595
Other	629	847
Total accounts receivable - net	$ 53,326	$ 51,744

Accounts Receivable - Allowance

Accounts Receivable - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period	$ 1,816	$ 1,881	$ 1,881
Provision for bad debts	249	$ 286	628
Accounts written off, net of recoveries	(224)		(693)
Balance at end of period	$ 1,841		$ 1,816

Inventory (Details)

Inventory (Details) - USD ($)	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Inventory Disclosure [Abstract]
Used oil and processed oil	$ 8,664,000		$ 12,124,000
Solvents and solutions	7,983,000		8,216,000
Machines	5,988,000		5,334,000
Drums and supplies	5,098,000		5,231,000
Other	2,170,000		2,378,000
Total inventory	29,903,000		33,283,000
Less: machine refurbishing reserve	242,000		224,000
Total inventory - net	29,661,000		$ 33,059,000
Inventory write-down	$ 0	$ 0

Property, Plant, and Equipmen_2

Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Property, Plant and Equipment [Abstract]
Machinery, vehicles, and equipment	$ 100,350		$ 98,708
Buildings and storage tanks	69,977		69,791
Land	9,659		9,546
Leasehold improvements	5,738		5,701
Construction in progress	20,251		15,405
Assets held for sale	4		4
Total property, plant and equipment	205,979		199,155
Less: accumulated depreciation	61,183		59,168
Property, plant and equipment - net	144,796		139,987
Equipment at customers	74,113		73,075
Less: accumulated depreciation	50,274		49,261
Equipment at customers - net	23,839		$ 23,814
Depreciation expense	$ 3,100	$ 2,900

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Goodwill (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 23, 2019USD ($)reporting_unit	Dec. 29, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Number of reporting units | reporting_unit	2
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 36,310	$ 38,075
Accumulated impairment loss	(3,952)	(3,952)
Goodwill [Roll Forward]
Net book value, beginning balance	34,123
Measurement period adjustments		0
Net book value, ending balance	32,358	34,123
Oil Business
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	3,952	3,952
Accumulated impairment loss	(3,952)	(3,952)
Goodwill [Roll Forward]
Net book value, beginning balance	0
Measurement period adjustments		0
Net book value, ending balance	0	0
Environmental Services
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	32,358	34,123
Accumulated impairment loss	0	0
Goodwill [Roll Forward]
Net book value, beginning balance	34,123
Measurement period adjustments		(1,765)
Net book value, ending balance	$ 32,358	$ 34,123

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Summary of Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 38,305		$ 34,874
Accumulated Amortization	21,235		20,193
Net Carrying Amount	17,070		14,681
Amortization of intangible assets	1,000	$ 700
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2019	2,400
2020	3,000
2021	2,800
2022	2,600
2023	2,100
Customer & supplier relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	25,020		23,686
Accumulated Amortization	12,001		11,445
Net Carrying Amount	$ 13,019		12,241
Useful life	11 years
Software
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 6,446		5,040
Accumulated Amortization	4,452		4,094
Net Carrying Amount	$ 1,994		946
Useful life	10 years
Non-compete agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,369		2,937
Accumulated Amortization	2,952		2,904
Net Carrying Amount	$ 417		33
Useful life	5 years
Patents, formulae, and licenses
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,769		1,769
Accumulated Amortization	723		708
Net Carrying Amount	$ 1,046		1,061
Useful life	15 years
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,701		1,442
Accumulated Amortization	1,107		1,042
Net Carrying Amount	$ 594		$ 400
Useful life	7 years

Accounts Payable (Details)

Accounts Payable (Details) - USD ($) $ in Thousands	Mar. 23, 2019	Dec. 29, 2018
Payables and Accruals [Abstract]
Accounts payable	$ 34,459	$ 32,471
Accounts payable - related parties	399	159
Total accounts payable	$ 34,858	$ 32,630

Debt and Financing Arrangemen_3

Debt and Financing Arrangements - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Debt Instrument [Line Items]
Interest costs incurred	$ 400,000
Amortization of debt issuance costs	$ 100,000
Weighted average interest rate	4.50%	3.40%
Letters of credit outstanding	$ 1,200,000		$ 1,300,000
Current borrowing capacity	63,800,000		$ 63,700,000
Term Loan
Debt Instrument [Line Items]
Interest costs incurred	$ 300,000	$ 300,000
Credit Agreement
Debt Instrument [Line Items]
Minimum interest coverage ratio	3.5
Maximum total leverage ratio	3
Aggregate consideration limit	$ 10,000,000
Leverage ratio at time of acquisition	3.25
Capital expenditures covenant limit	$ 100,000,000
Percentage of EBITDA	35.00%
Credit Agreement | Bank Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 95,000,000
Credit Agreement | Bank Credit Facility | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Credit Agreement | Bank Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Credit Agreement | Bank Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
Credit Agreement | Bank Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%
Credit Agreement | Bank Credit Facility | Bank of America's Prime Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.75%
Credit Agreement | Bank Credit Facility | Bank of America's Prime Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
Credit Agreement | Term Loan
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 30,000,000
Credit Agreement | Revolving Loan Portion
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 65,000,000

Debt and Financing Arrangemen_4

Debt and Financing Arrangements - Summary of Debt (Details) - USD ($) $ in Thousands	Mar. 23, 2019	Dec. 29, 2018
Debt Disclosure [Abstract]
Principal amount	$ 30,000	$ 30,000
Less: unamortized debt issuance costs	884	954
Debt less unamortized debt issuance costs	$ 29,116	$ 29,046

Segment Information - Operating

Segment Information - Operating Segment Results (Details) $ in Thousands	3 Months Ended
	Mar. 23, 2019USD ($)segment	Mar. 24, 2018USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	2
Revenues
Revenues	$ 95,772	$ 83,147
Rental income	3,548	0
Operating expenses
Operating costs	82,483	68,386
Operating depreciation and amortization	3,070	2,879
Profit (loss) before corporate selling, general, and administrative expenses	10,219	11,882
Selling, general, and administrative expenses	12,396	11,022
Depreciation and amortization from SG&A	1,066	764
Total selling, general, and administrative expenses	13,462	11,786
Other (income) expense - net	(58)	389
Operating loss	(3,185)	(293)
Interest expense – net	230	245
Loss before income taxes	(3,415)	(538)
Corporate and Eliminations
Revenues
Revenues	0	0
Rental income	0
Operating expenses
Operating costs	0	0
Operating depreciation and amortization	0	0
Profit (loss) before corporate selling, general, and administrative expenses	0	0
Selling, general, and administrative expenses	12,396	11,022
Depreciation and amortization from SG&A	1,066	764
Total selling, general, and administrative expenses	13,462	11,786
Other (income) expense - net	(58)	389
Interest expense – net	230	245
Environmental Services
Revenues
Revenues	66,496
Environmental Services | Segments
Revenues
Revenues	66,496	57,476
Rental income	3,484
Operating expenses
Operating costs	50,163	42,725
Operating depreciation and amortization	1,636	1,490
Profit (loss) before corporate selling, general, and administrative expenses	14,697	13,261
Oil Business
Revenues
Revenues	29,276
Oil Business | Segments
Revenues
Revenues	29,276	25,671
Rental income	64
Operating expenses
Operating costs	32,320	25,661
Operating depreciation and amortization	1,434	1,389
Profit (loss) before corporate selling, general, and administrative expenses	(4,478)	(1,379)
Service revenues
Revenues
Revenues	56,366	54,137
Service revenues | Corporate and Eliminations
Revenues
Revenues	0	0
Service revenues | Environmental Services | Segments
Revenues
Revenues	52,875	51,032
Service revenues | Oil Business | Segments
Revenues
Revenues	3,491	3,105
Product revenues
Revenues
Revenues	35,858	29,010
Product revenues | Corporate and Eliminations
Revenues
Revenues	0	0
Product revenues | Environmental Services | Segments
Revenues
Revenues	10,137	6,444
Product revenues | Oil Business | Segments
Revenues
Revenues	$ 25,721	$ 22,566

Segment Information - Assets by

Segment Information - Assets by Segment (Details) - USD ($) $ in Thousands	Mar. 23, 2019	Dec. 29, 2018
Segment Reporting Information [Line Items]
Assets	$ 411,585	$ 347,822
Segments | Environmental Services
Segment Reporting Information [Line Items]
Assets	197,092	148,192
Segments | Oil Business
Segment Reporting Information [Line Items]
Assets	157,383	142,691
Unallocated Corporate Assets
Segment Reporting Information [Line Items]
Assets	$ 57,110	$ 56,939

Commitments and Contingencies_2

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	Mar. 23, 2019	Dec. 29, 2018
Lessee, Lease, Description [Line Items]
Remaining lease term	4 years 4 months 24 days
Remaining amount committed	$ 19	$ 18.6
Loss contingency accrual	$ 4.4	$ 4.2
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 month
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	11 years
Lease renewal term	5 years

Commitments and Contingencies_3

Commitments and Contingencies - Components of Lease Expense (Details) $ in Thousands	3 Months Ended
	Mar. 23, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 6,031
Short-term lease cost	1,404
Variable lease cost	1,093
Total lease cost	8,528
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	6,341
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 67,593
Weighted-average remaining lease term	4 years 4 months 24 days
Weighted-average discount rate	5.50%

Commitments and Contingencies_4

Commitments and Contingencies - Future Annual Minimum Lease Payment Commitments (Details) $ in Thousands	Mar. 23, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
2019	$ 16,705
2020	16,997
2021	13,355
2022	10,139
2023	6,887
2024 and thereafter	6,822
Total minimum lease payments	70,905
Less: imputed interest	8,174
Lease liability	$ 62,731

Commitments and Contingencies_5

Commitments and Contingencies - Rental Income (Details) $ in Thousands	3 Months Ended
	Mar. 23, 2019USD ($)
Lessor, Lease, Description [Line Items]
Total rental income	$ 3,548
Environmental Services
Lessor, Lease, Description [Line Items]
Total rental income	3,484
Oil Business
Lessor, Lease, Description [Line Items]
Total rental income	64
Parts Cleaning
Lessor, Lease, Description [Line Items]
Total rental income	3,484
Parts Cleaning | Environmental Services
Lessor, Lease, Description [Line Items]
Total rental income	3,484
Parts Cleaning | Oil Business
Lessor, Lease, Description [Line Items]
Total rental income	0
Railcars
Lessor, Lease, Description [Line Items]
Total rental income	57
Railcars | Environmental Services
Lessor, Lease, Description [Line Items]
Total rental income	0
Railcars | Oil Business
Lessor, Lease, Description [Line Items]
Total rental income	57
Property
Lessor, Lease, Description [Line Items]
Total rental income	7
Property | Environmental Services
Lessor, Lease, Description [Line Items]
Total rental income	0
Property | Oil Business
Lessor, Lease, Description [Line Items]
Total rental income	$ 7

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018
Income Tax Disclosure [Abstract]
Net operating loss	$ 26.2
Deferred tax asset, state and federal NOL	$ 5.9
Effective tax rate	28.90%	81.10%
Reserve balance	$ 2.5

Share-based Compensation - Stoc

Share-based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 23, 2019	Dec. 29, 2018	May 01, 2019
Number of Options Outstanding
Options outstanding at Beginning of Period (in shares)	2,760
Exercised (in shares)	(2,760)
Options outstanding at End of Period (in shares)	0	2,760
Weighted Average Exercise Price
Options outstanding at Beginning of Period (in dollars per share)	$ 7.33
Exercised (in dollars per share)	7.33
Options outstanding at End of Period (in dollars per share)	$ 0	$ 7.33
Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value as of Date Listed
Weighted average remaining contractual term (in years)	0 years	2 months 27 days
Aggregate intrinsic value as of date listed	$ 0	$ 41
Subsequent event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant			1,500,000

Share-based Compensation - Rest

Share-based Compensation - Restricted Stock Compensation/Awards (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2017	Mar. 23, 2019
Mr. Recatto
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing share price as of employment commencement date (in dollars per share)	$ 15
Restricted stock | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)		1 year
Restricted stock | Members of Management
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)		3 years
Restricted stock | Mr. Recatto
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	500,000
Vesting threshold (in dollars per share)	$ 5
Shares vested upon achievement of share price threshold (in shares)	0
Compensation Expense		$ 0.2
Unrecognized compensation expense		$ 1
Risk-free rate	1.70%
Expected dividend yield	0.00%
Expected volatility rate	41.73%
Restricted stock | Mr. Recatto | Less than $5 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)		180 days
Vesting percentage	0.00%	50.00%

Share-based Compensation - Sche

Share-based Compensation - Schedule of Restricted Stock Unit Activity (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended
	May 31, 2018	Apr. 30, 2018	Feb. 28, 2018	Feb. 28, 2017	Mar. 23, 2019	Mar. 24, 2018	Dec. 29, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)					0
Restricted stock | Members of Management | February, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)				146,564
Compensation Expense					$ 89	$ 99
Unrecognized compensation expense					296		$ 385
Restricted stock | Members of Management | February, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)			116,958
Compensation Expense					136	122
Unrecognized compensation expense					1,040		1,176
Restricted stock | Members of Management | April, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)		350,000
Compensation Expense					163	0
Unrecognized compensation expense					5,192		6,633
Restricted stock | Chief Executive Officer | February, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)				500,000
Compensation Expense					205	511
Unrecognized compensation expense					1,025		1,230
Restricted stock | Board of Directors | May, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted (in shares)	13,800
Compensation Expense					0	$ 66
Unrecognized compensation expense					$ 0		$ 0

Share-based Compensation - Re_2

Share-based Compensation - Restricted Stock Vesting Schedule by Percentage (Details) - $ / shares	Mar. 14, 2018	Feb. 28, 2017	Mar. 23, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			82,072
Mr. Recatto | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	125,000
Mr. Recatto | Restricted stock | Less than $5 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share)		$ 5
Total percentage of Restricted Stock Shares to Be Vested		0.00%	50.00%
Mr. Recatto | Restricted stock | $5 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share)		$ 5
Total percentage of Restricted Stock Shares to Be Vested	25.00%	25.00%
Mr. Recatto | Restricted stock | $10 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share)		$ 10
Total percentage of Restricted Stock Shares to Be Vested		50.00%
Mr. Recatto | Restricted stock | $15 per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share)		$ 15
Total percentage of Restricted Stock Shares to Be Vested		75.00%
Mr. Recatto | Restricted stock | $20 or more per share increase
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in stock price from employment commencement date (in dollars per share)		$ 20
Total percentage of Restricted Stock Shares to Be Vested		100.00%

Share-based Compensation - Nonv

Share-based Compensation - Nonvested Restricted Stock (Details)	3 Months Ended
	Mar. 23, 2019$ / sharesshares
Number of Shares
Nonvested shares outstanding at Beginning of Period (in shares) | shares	1,013,863
Granted (in shares) | shares	0
Vested (in shares) | shares	(82,072)
Forfeited (in shares) | shares	(65,641)
Nonvested shares outstanding at End of Period (in shares) | shares	866,150
Weighted Average Grant-Date Fair Value Per Share
Nonvested shares outstanding at Beginning of Period (in dollars per share) | $ / shares	$ 18.20
Granted (in dollars per share) | $ / shares	0
Vested (in dollars per share) | $ / shares	16.99
Forfeited (in dollars per share) | $ / shares	22.04
Nonvested shares outstanding at End of Period (in dollars per share) | $ / shares	$ 18.02

Share-based Compensation - Empl

Share-based Compensation - Employee Stock Purchase Plan (Details) - $ / shares	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018
Common stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Issuance of common stock – ESPP (in shares)	4,975	4,822
Employee Stock Purchase Plan | Employee stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares available employee stock purchase plan (in shares)	124,287
Weighted average fair value per share ESPP (in dollars per share)	$ 23.54

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018
Earnings Per Share [Abstract]
Net loss	$ (2,429)	$ (102)
Less: income attributable to noncontrolling interest	83	18
Net loss attributable to Heritage-Crystal Clean, Inc. common stockholders	$ (2,512)	$ (120)
Weighted average basic shares outstanding (in shares)	23,117	22,962
Weighted average diluted shares outstanding (in shares)	23,117	22,962
Number of anti–dilutive potentially issuable shares excluded from diluted shares outstanding	248	170
Net loss per share: basic (in dollars per share)	$ (0.11)	$ (0.01)
Net loss per share: diluted (in dollars per share)	$ (0.11)	$ (0.01)

Other (Income) Expense - Net (D

Other (Income) Expense - Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 23, 2019	Mar. 24, 2018
Restructuring Cost and Reserve [Line Items]
Other (income) expense - net	$ (58)	$ 389
Facility closing
Restructuring Cost and Reserve [Line Items]
Other (income) expense - net		$ 300

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent event - All Valley Disposal, Inc. $ in Millions	Mar. 25, 2019USD ($)
Subsequent Event [Line Items]
Initial payment	$ 0.6
Maximum
Subsequent Event [Line Items]
Purchase price	$ 1.3

Uncategorized Items - hcci-2019

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (268,000)
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(268,000)
Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (268,000)