Clean Harbors (CLH) 10-Q 3 May 17 2017 Q1 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - shares	3 Months Ended
	Mar. 31, 2017	Apr. 28, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	CLEAN HARBORS INC
Entity Central Index Key	822,818
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		57,209,487

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 297,366	$ 306,997
Accounts receivable, net of allowances aggregating $27,144 and $29,249, respectively	480,044	496,226
Unbilled accounts receivable	28,106	36,190
Deferred costs	19,037	18,914
Inventories and supplies	182,038	178,428
Prepaid expenses and other current assets	55,180	56,116
Total current assets	1,061,771	1,092,871
Property, plant and equipment, net	1,609,490	1,611,827
Other assets:
Goodwill	469,860	465,154
Permits and other intangibles, net	490,952	498,721
Other	13,580	13,347
Total other assets	974,392	977,222
Total assets	3,645,653	3,681,920
Current liabilities:
Accounts payable	218,676	229,534
Deferred revenue	64,379	64,397
Accrued expenses	183,957	190,721
Current portion of closure, post-closure and remedial liabilities	21,569	20,016
Total current liabilities	488,581	504,668
Other liabilities:
Closure and post-closure liabilities, less current portion of $6,019 and $6,220, respectively	54,332	52,111
Remedial liabilities, less current portion of $15,550 and $13,796, respectively	111,057	114,211
Long-term obligations	1,633,968	1,633,272
Deferred taxes, unrecognized tax benefits and other long-term liabilities	294,085	293,417
Total other liabilities	2,093,442	2,093,011
Commitments and contingent liabilities (See Note 15)
Stockholders’ equity:
Common Stock, $.01 par value: Authorized 80,000,000; shares issued and outstanding 57,188,805 and 57,297,978 shares, respectively	572	573
Shares held under employee participation plan	0	(469)
Additional paid-in capital	720,383	725,670
Accumulated other comprehensive loss	(208,275)	(214,326)
Accumulated earnings	550,950	572,793
Total stockholders’ equity	1,063,630	1,084,241
Total liabilities and stockholders’ equity	$ 3,645,653	$ 3,681,920

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Account receivable, allowances aggregating	$ 27,144	$ 29,249
Closure and post-closure liabilities, current portion	6,019	6,220
Remedial liabilities, current portion	$ 15,550	$ 13,796
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, authorized shares (in shares)	80,000,000	80,000,000
Common stock, issued shares (in shares)	57,188,805	57,297,978
Common stock, outstanding shares (in shares)	57,188,805	57,297,978

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues:
Service revenues	$ 560,214	$ 530,231
Product revenues	128,727	105,852
Total revenues	688,941	636,083
Cost of revenues (exclusive of items shown separately below)
Service revenues	391,087	373,986
Product revenues	105,498	90,293
Total cost of revenues	496,585	464,279
Selling, general and administrative expenses	112,221	104,484
Accretion of environmental liabilities	2,290	2,505
Depreciation and amortization	72,412	68,902
(Loss) income from operations	5,433	(4,087)
Other expense	(1,549)	(350)
Interest expense, net of interest income of $215 and $150, respectively	(22,576)	(18,980)
(Loss) income before (benefit) provision for income taxes	(18,692)	(23,417)
Provision (benefit) for income taxes	2,701	(2,546)
Net loss	$ (21,393)	$ (20,871)
Loss per share:
Basic (in USD per share)	$ (0.37)	$ (0.36)
Diluted (in USD per share)	$ (0.37)	$ (0.36)
Shares used to compute loss per share - Basic (in shares)	57,262	57,617
Shares used to compute loss per share - Diluted (in shares)	57,262	57,617

UNAUDITED CONSOLIDATED STATEME5

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Interest expense	$ 215	$ 150

UNAUDITED CONSOLIDATED STATEME6

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (21,393)	$ (20,871)
Other comprehensive income:
Unrealized gains on available-for-sale securities (net of taxes of $152 and $0, respectively)	82	0
Reclassification adjustment for losses on available-for-sale securities included in net loss (net of taxes of $0 and $0, respectively)	146	0
Foreign currency translation adjustments	5,823	45,837
Other comprehensive income	6,051	45,837
Comprehensive (loss) income	$ (15,342)	$ 24,966

UNAUDITED CONSOLIDATED STATEME7

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Unrealized gains (losses) on available-for-sale securities, taxes	$ 152	$ 0
Reclassification adjustment for gains on available-for-sale securities included in net (loss) income taxes	$ 0	$ 0

UNAUDITED CONSOLIDATED STATEME8

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net loss	$ (21,393)	$ (20,871)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation and amortization	72,412	68,902
Allowance for doubtful accounts	1,935	1,072
Amortization of deferred financing costs and debt discount	829	872
Accretion of environmental liabilities	2,290	2,505
Changes in environmental liability estimates	102	(95)
Deferred income taxes	196	7
Stock-based compensation	2,271	2,093
Net tax deficiency on stock based awards	0	(345)
Other expense	1,549	350
Environmental expenditures	(2,938)	(3,518)
Changes in assets and liabilities, net of acquisitions
Accounts receivable and unbilled accounts receivable	24,301	35,839
Inventories and supplies	(2,676)	(2,882)
Other current assets	(1,277)	1,838
Accounts payable	(13,609)	(36,195)
Other current and long-term liabilities	(6,873)	(10,283)
Net cash from operating activities	57,119	39,289
Cash flows used in investing activities:
Additions to property, plant and equipment	(42,462)	(75,781)
Proceeds from sales of fixed assets	1,030	1,273
Acquisitions, net of cash acquired	(11,946)	(34,993)
Proceeds on sale of business	2,018	0
Additions to intangible assets, including costs to obtain or renew permits	(751)	(512)
Proceeds from sale of investments	243	0
Net cash used in investing activities	(51,868)	(110,013)
Cash flows (used in) from financing activities:
Change in uncashed checks	(7,557)	(5,218)
Proceeds from exercise of stock options	46	0
Issuance of restricted shares, net of shares remitted	(1,021)	(1,425)
Repurchases of common stock	(6,796)	(4,998)
Deferred financing costs paid	(108)	(2,190)
Issuance of senior secured notes, including premium	0	250,625
Net cash (used in) from financing activities	(15,436)	236,794
Effect of exchange rate change on cash	554	4,567
(Decrease) increase in cash and cash equivalents	(9,631)	170,637
Cash and cash equivalents, beginning of period	306,997	184,708
Cash and cash equivalents, end of period	297,366	355,345
Cash payments for interest and income taxes:
Interest paid	21,717	21,808
Income taxes paid	5,519	5,848
Non-cash investing and financing activities:
Property, plant and equipment accrued	19,270	14,947
Receivable for estimated purchase price adjustment	$ 1,972	$ 250

UNAUDITED CONSOLIDATED STATEME9

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Shares Held Under Employee Participation Plan	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Earnings
Increase (Decrease) in Stockholders' Equity
Cumulative effect of change in accounting for Stock based compensation	$ 231			$ 681		$ (450)
Balance at beginning of period at Dec. 31, 2016	1,084,241	$ 573	$ (469)	725,670	$ (214,326)	572,793
Balance beginning of period (in shares) at Dec. 31, 2016		57,298
Increase (Decrease) in Stockholders' Equity
Net loss	(21,393)					(21,393)
Other comprehensive income	6,051				6,051
Stock-based compensation	2,271			2,271
Issuance of restricted shares, net of shares remitted	(1,021)	$ 0		(1,021)
Issuance of restricted shares, net of shares remitted (in shares)		34
Shares held under employee participation plan	0	$ 0	469	(469)
Shares held under employee participation plan (in shares)		(25)
Repurchases of common stock	$ (6,796)	$ (1)		(6,795)
Repurchases of common stock (in shares)	(100)	(120)
Exercise of stock options	$ 46			46
Exercise of stock options (in shares)		2
Balance at end of period at Mar. 31, 2017	$ 1,063,630	$ 572	$ 0	$ 720,383	$ (208,275)	$ 550,950
Balance ending of period (in shares) at Mar. 31, 2017		57,189

UNAUDITED CONSOLIDATED STATEM10

UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS'S EQUITY (PARENTHETICAL) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Common stock, par value (in USD per share)	$ 0.01	$ 0.01

BASIS OF PRESENTATION

BASIS OF PRESENTATION	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION The accompanying consolidated interim financial statements are unaudited and include the accounts of Clean Harbors, Inc. and its subsidiaries (collectively, “Clean Harbors,” the “Company” or "we") and have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) and, in the opinion of management, include all adjustments which are of a normal recurring nature, necessary for a fair presentation of the financial position, results of operations, and cash flows for the periods presented. Management has made estimates and assumptions affecting the amounts reported in the Company's consolidated interim financial statements and accompanying footnotes, actual results could differ from those estimates and judgments. The results for interim periods are not necessarily indicative of results for the entire year or any other interim periods. The financial statements presented herein should be read in connection with the financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 , which includes the audited consolidated balance sheet as of December 31, 2016 from which the one presented herein was derived.

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES The Company's significant accounting policies are described in Note 2, "Significant Accounting Policies," in the Company's Annual Report on Form 10-K for the year ended December 31, 2016 . There have been no material changes in these policies or their application. Reclassifications As disclosed in the Company's Annual Report on Form 10-K for the year ended December 31, 2016 , in the fourth quarter of 2016 the Company changed the manner in which it manages its business, makes operating decisions and assesses the Company's performance. The Company's operations are now managed in six operating segments: Technical Services, Industrial Services, Field Services, Safety-Kleen, Oil and Gas Field Services and Lodging Services. For purposes of segment disclosure the Industrial Services and Field Services operating segments have been aggregated into a single reportable segment based upon their similar economic and other characteristics, and the Oil and Gas Field Services and Lodging Services operating segments have been combined as they do not meet the quantitative thresholds for separate presentation. The amounts presented for the three months ended March 31, 2016 have been recast to reflect the impact of such changes. These reclassifications and adjustments had no effect on consolidated net loss, comprehensive (loss) income, cash flows or stockholders' equity for any of the periods presented. Recent Accounting Pronouncements Standards implemented In July 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-11, Inventory (Topic 330). The amendment provides guidance regarding the measurement of inventory. Entities should measure inventory within the scope of this update at the lower of cost and net realizable value. The adoption of ASU 2015-11 was applied prospectively and as of January 1, 2017 did not have an impact on the Company's consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendment simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. Stock-based compensation excess tax benefits or deficiencies are now reflected in the Consolidated Statements of Operations as a component of the provision for income taxes, whereas they previously were recognized in equity. Additionally, the Consolidated Statements of Cash Flows now include excess tax benefits as an operating activity. Previously, income tax benefits at settlement of an award were reported as a reduction to operating cash flows and an increase to financing cash flows to the extent that those benefits exceeded the income tax benefits reported in earnings during the award's vesting period. The Company has elected to apply that change in cash flow classification on a prospective basis, leaving previously reported net cash from operating activities and net cash from financing activities in the accompanying Consolidated Statement of Cash Flows for the period ended March 31, 2016 unchanged. Finally, the Company has elected to account for forfeitures as they occur, rather than estimate expected forfeitures. As a result of the adoption of this update, the Company recorded a cumulative-effect adjustment that reduced beginning retained earnings by $ 0.5 million , net of tax. Standard to be implemented In May 2014, FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) . ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. In August 2015, FASB issued ASU 2015-14 which deferred the effective date of ASU 2014-09 for all entities by one year. In March 2016, FASB issued ASU 2016-08, which reduces the potential for diversity in practice arising from inconsistent application of the principal versus agent guidance, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In April 2016, FASB issued ASU 2016-10, which reduces the potential for diversity in initial application, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In May 2016, FASB issued ASU 2016-12, which provided narrow scope improvements and practical expedients on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. ASU 2014-09 is currently effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2017. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the cumulative catch-up transition method). The Company expects that it will adopt ASU 2014‑09 beginning in the first quarter of 2018 and continues its evaluation of the impact of the new standard on its accounting policies, processes, and system requirements. The Company has assigned internal resources to assist in this implementation project and believes that the project is progressing timely. A final decision regarding the adoption method has not been finalized at this time. The Company’s final determination will depend on a number of factors, such as the significance of the impact of the new standard on its financial results, system readiness, and its ability to accumulate and analyze the information necessary to assess the impact on prior period financial statements, as necessary. In February 2017, the FASB issued ASU 2017-05, Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets . The amendments in this Update are meant to clarify the scope of ASC Subtopic 610-20, Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets and to add guidance for partial sales of nonfinancial assets. The amendments in this Update should be applied using a full retrospective method or a modified retrospective method and are effective at the same time as ASU 2014-09. Further, the Company is required to adopt ASU 2017-05 at the same time that it adopts the guidance in ASU 2014-09. Adoption is not expected to have a material impact on the Company's consolidated financial statements.

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS 2017 Acquisitions On January 31, 2017, the Company acquired a privately held company for a purchase price of approximately $ 11.9 million in cash, net of cash acquired, and subject to customary post-closing adjustments. The acquired business produces and distributes oil products and therefore complements the Company's closed loop model as it relates to the sale of its oil products. The acquired company is included in the Safety-Kleen operating segment. In connection with this acquisition a preliminary goodwill amount of $ 4.9 million was recognized. 2016 Acquisitions During 2016 , the Company acquired seven businesses that complement the strategy to create a closed loop model as it relates to the sale of the Company's oil products. These acquisitions provided the Company with three additional oil re-refineries while also expanding its used motor oil collection network and providing greater blending and packaging capabilities. These acquisitions also provide the Company with greater access to customers in the West Coast region of the United States and additional locations with Part B permits. Operations of these acquisitions are primarily being integrated into the Safety-Kleen operating segment with certain operations also being integrated into the Technical Services and Industrial Services operating segments. The combined purchase price for the seven acquisitions was approximately $205.0 million in cash, net of cash acquired, and subject to customary post-closing adjustments. The purchase price allocation for acquisitions may reflect various fair value estimates and analysis, including preliminary work performed by third-party valuation specialists. In addition, purchase prices for acquisitions may reflect preliminary working capital based adjustments. These estimates are subject to change within the measurement period as valuations and working capital adjustments are finalized. The primary areas of the preliminary purchase price allocation that are subject to change relate to the fair values of certain tangible assets and liabilities acquired, the valuation of intangible assets acquired, certain legal matters, income and income based taxes, and residual goodwill. Measurement period adjustments are recorded in the reporting period in which the estimates are finalized and adjustment amounts are determined. The components and preliminary allocation of the purchase price consist of the following amounts (in thousands): At Acquisition Dates As Reported Measurement Period Adjustments At Acquisition Dates As Reported Accounts receivable $ 15,767 $ 629 $ 16,396 Inventories and supplies 12,515 173 12,688 Prepaid expenses and other current assets 777 (25 ) 752 Property, plant and equipment 143,025 625 143,650 Permits and other intangibles 28,856 — 28,856 Current liabilities (20,258 ) 392 (19,866 ) Closure and post-closure liabilities (2,408 ) (596 ) (3,004 ) Remedial liabilities, less current portion (2,041 ) 16 (2,025 ) Deferred taxes, unrecognized tax benefits and other long-term liabilities (17,019 ) (456 ) (17,475 ) Total identifiable net assets 159,214 758 159,972 Goodwill 45,791 (731 ) 45,060 Total purchase price, net of cash acquired $ 205,005 $ 27 $ 205,032 The excess of the total purchase price, which includes the aggregate cash consideration paid in excess of the fair value of the tangible net assets and intangible asset acquired, was recorded as goodwill. The goodwill recognized is attributable to the expected operating synergies and growth potential that the Company expects to realize from these acquisitions. Goodwill generated from the acquisitions was not deductible for tax purposes. Pro forma revenue and earnings amounts on a combined basis as if these acquisitions had been completed on January 1, 2016 are immaterial to the consolidated financial statements of the Company since that date.

DISPOSITION OF BUSINESS

DISPOSITION OF BUSINESS	3 Months Ended
	Mar. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
DISPOSITION OF BUSINESS	DISPOSITION OF BUSINESS On September 1, 2016, the Company completed the sale of its Catalyst Services business, which was a non-core business previously included within the Industrial and Field Services segment. During the first quarter of 2017, the Company and the buyer of the Catalyst Services business agreed to final working capital amounts and as a result the Company received $2.0 million of final sale proceeds. The following table presents the loss before benefit for income taxes attributable to the Catalyst Services business included in the Company's consolidated results of operations for three months ended March 31, 2016 (in thousands): Three Months Ended March 31, 2016 Loss before benefit for income taxes 1,099

INVENTORIES AND SUPPLIES

INVENTORIES AND SUPPLIES	3 Months Ended
	Mar. 31, 2017
Inventory Disclosure [Abstract]
INVENTORIES AND SUPPLIES	INVENTORIES AND SUPPLIES Inventories and supplies consisted of the following (in thousands): March 31, 2017 December 31, 2016 Oil and oil products $ 55,872 $ 52,158 Supplies and drums 91,210 90,610 Solvent and solutions 8,865 8,566 Modular camp accommodations 14,859 15,255 Other 11,232 11,839 Total inventories and supplies $ 182,038 $ 178,428 As of March 31, 2017 and December 31, 2016 , other inventories consisted primarily of cleaning fluids, such as absorbents and wipers, and automotive fluids, such as windshield washer fluid and antifreeze.

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consisted of the following (in thousands): March 31, 2017 December 31, 2016 Land $ 122,184 $ 120,575 Asset retirement costs (non-landfill) 15,173 14,567 Landfill assets 140,518 139,708 Buildings and improvements 406,562 373,160 Camp equipment 151,561 152,740 Vehicles 558,175 541,022 Equipment 1,591,511 1,483,736 Furniture and fixtures 5,507 5,492 Construction in progress 42,305 146,904 3,033,496 2,977,904 Less - accumulated depreciation and amortization 1,424,006 1,366,077 Total property, plant and equipment, net $ 1,609,490 $ 1,611,827 Interest in the amount of $0.1 million and $1.2 million was capitalized to fixed assets during the three months ended March 31, 2017 and March 31, 2016 , respectively. Depreciation expense, inclusive of landfill amortization, was $63.3 million and $59.3 million for the three months ended March 31, 2017 and March 31, 2016 , respectively.

GOODWILL AND OTHER INTANGIBLE A

GOODWILL AND OTHER INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND OTHER INTANGIBLE ASSETS	GOODWILL AND OTHER INTANGIBLE ASSETS The changes in goodwill for the three months ended March 31, 2017 were as follows (in thousands): Technical Services Industrial & Field Services Safety-Kleen Oil, Gas and Lodging Services Totals Balance at January 1, 2017 $ 61,116 $ 107,968 $ 296,070 $ — $ 465,154 Increase from current period acquisitions — — 4,938 — 4,938 Measurement period adjustments from prior period acquisitions — — (731 ) — (731 ) Foreign currency translation and other 42 163 294 — 499 Balance at March 31, 2017 $ 61,158 $ 108,131 $ 300,571 $ — $ 469,860 The Company assesses goodwill for impairment on an annual basis as of December 31, or at an interim date when events or changes in the business environment would more likely than not reduce the fair value of a reporting unit below its carrying value. The Company conducted the annual impairment test of goodwill for all reporting units as of December 31, 2016 and determined that no adjustment to the carrying value of goodwill for any reporting units was necessary because the fair value of each of the reporting units exceeded that reporting unit's respective carrying value. As of March 31, 2017 and December 31, 2016 , the Company's total finite-lived and indefinite-lived intangible assets consisted of the following (in thousands): March 31, 2017 December 31, 2016 Cost Accumulated Net Weighted Cost Accumulated Net Weighted Permits $ 172,666 $ 69,151 $ 103,515 19.8 $ 171,637 $ 67,301 $ 104,336 18.9 Customer and supplier relationships 394,086 134,599 259,487 11.9 393,426 127,462 265,964 12.2 Other intangible assets 34,463 29,228 5,235 7.1 34,254 28,456 5,798 7.1 Total amortizable permits and other intangible assets 601,215 232,978 368,237 14.9 599,317 223,219 376,098 13.9 Trademarks and trade names 122,715 — 122,715 Indefinite 122,623 — 122,623 Indefinite Total permits and other intangible assets $ 723,930 $ 232,978 $ 490,952 $ 721,940 $ 223,219 $ 498,721 Amortization expense of permits and other intangible assets was $9.1 million and $9.6 million for the three months ended March 31, 2017 and March 31, 2016 , respectively. The expected amortization of the net carrying amount of finite-lived intangible assets at March 31, 2017 was as follows (in thousands): Years Ending December 31, Expected Amortization 2017 (nine months) $ 27,392 2018 34,072 2019 31,275 2020 29,067 2021 26,640 Thereafter 219,791 $ 368,237

ACCRUED EXPENSES

ACCRUED EXPENSES	3 Months Ended
	Mar. 31, 2017
Payables and Accruals [Abstract]
ACCRUED EXPENSES	ACCRUED EXPENSES Accrued expenses consisted of the following at March 31, 2017 and December 31, 2016 (in thousands): March 31, 2017 December 31, 2016 Insurance $ 56,603 $ 63,061 Interest 21,770 21,536 Accrued compensation and benefits 41,109 34,641 Income, real estate, sales and other taxes 29,814 35,083 Other 34,661 36,400 $ 183,957 $ 190,721 As of March 31, 2017 and December 31, 2016 , other accrued expenses included accrued legal matters of $4.2 million and $3.8 million , respectively, and accrued severance charges of $2.3 million and $2.9 million , respectively.

CLOSURE AND POST-CLOSURE LIABIL

CLOSURE AND POST-CLOSURE LIABILITIES	3 Months Ended
	Mar. 31, 2017
Asset Retirement Obligation Disclosure [Abstract]
CLOSURE AND POST-CLOSURE LIABILITIES	CLOSURE AND POST-CLOSURE LIABILITIES The changes to closure and post-closure liabilities (also referred to as “asset retirement obligations”) from January 1, 2017 through March 31, 2017 were as follows (in thousands): Landfill Non-Landfill Total Balance at January 1, 2017 $ 30,630 $ 27,701 $ 58,331 Measurement period adjustments from prior period acquisitions — 596 596 New asset retirement obligations 431 — 431 Accretion 534 623 1,157 Changes in estimates recorded to statement of operations — (6 ) (6 ) Expenditures (119 ) (73 ) (192 ) Currency translation and other 20 14 34 Balance at March 31, 2017 $ 31,496 $ 28,855 $ 60,351 All of the landfill facilities included in the above were active as of March 31, 2017 . There were no significant charges (benefits) in 2017 resulting from changes in estimates for closure and post-closure liabilities. New asset retirement obligations incurred during the first three months of 2017 were discounted at the credit-adjusted risk-free rate of 6.12% .

REMEDIAL LIABILITIES

REMEDIAL LIABILITIES	3 Months Ended
	Mar. 31, 2017
Environmental Remediation Obligations [Abstract]
REMEDIAL LIABILITIES	REMEDIAL LIABILITIES The changes to remedial liabilities for the three months ended March 31, 2017 were as follows (in thousands): Remedial Liabilities for Landfill Sites Remedial Liabilities for Inactive Sites Remedial Liabilities (Including Superfund) for Non-Landfill Operations Total Balance at January 1, 2017 $ 1,777 $ 64,151 $ 62,079 $ 128,007 Measurement period adjustments from prior period acquisitions — — (16 ) (16 ) Accretion 21 615 497 1,133 Changes in estimates recorded to statement of operations (38 ) (94 ) 240 108 Expenditures (7 ) (720 ) (2,019 ) (2,746 ) Currency translation and other — 8 113 121 Balance at March 31, 2017 $ 1,753 $ 63,960 $ 60,894 $ 126,607 In the three months ended March 31, 2017 , there were no significant charges (benefits) resulting from changes in estimates for remedial liabilities.

FINANCING ARRANGEMENTS

FINANCING ARRANGEMENTS	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
FINANCING ARRANGEMENTS	FINANCING ARRANGEMENTS The following table is a summary of the Company’s financing arrangements (in thousands): March 31, 2017 December 31, 2016 Senior unsecured notes, at 5.25%, due August 1, 2020 ("2020 Notes") $ 800,000 $ 800,000 Senior unsecured notes, at 5.125%, due June 1, 2021 ("2021 Notes") 845,000 845,000 Long-term obligations, at par $ 1,645,000 $ 1,645,000 Unamortized debt issuance costs and premium, net (11,032 ) (11,728 ) Long-term obligations, at carrying value $ 1,633,968 $ 1,633,272 At March 31, 2017 and December 31, 2016 , the fair value of the Company's 2020 Notes was $814.0 million and $820.0 million , respectively, based on quoted market prices for the instrument. At both March 31, 2017 and December 31, 2016 , the fair value of the Company's 2021 Notes was $861.9 million based on quoted market prices for the instrument. The fair value of the 2020 Notes and 2021 Notes are considered a Level 2 measure according to the fair value hierarchy. The Company also maintains a revolving credit facility which as of March 31, 2017 and December 31, 2016 , had no outstanding loan balances. At March 31, 2017 , approximately $194.0 million was available to borrow and outstanding letters of credit were $126.0 million . At December 31, 2016 , $195.2 million was available to borrow and outstanding letters of credit were $132.6 million .

LOSS PER SHARE

LOSS PER SHARE	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
LOSS PER SHARE	LOSS PER SHARE The following are computations of basic and diluted loss per share (in thousands except for per share amounts): Three Months Ended March 31, 2017 2016 Numerator for basic and diluted loss per share: Net loss $ (21,393 ) $ (20,871 ) Denominator: Basic shares outstanding 57,262 57,617 Dilutive effect of equity-based compensation awards — — Dilutive shares outstanding 57,262 57,617 Basic loss per share: $ (0.37 ) $ (0.36 ) Diluted loss per share: $ (0.37 ) $ (0.36 ) As a result of the net loss reported for the three months ended March 31, 2017 and 2016, all then outstanding restricted stock awards and performance awards totaling 659,558 and 474,318 , respectively, were excluded from the calculation of diluted loss per share as their inclusion would have an antidilutive effect.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE LOSS	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED OTHER COMPREHENSIVE LOSS The changes in accumulated other comprehensive loss by component and related tax effects for the three months ended March 31, 2017 were as follows (in thousands): Foreign Currency Translation Unrealized Gains on Available-For-Sale Securities Unfunded Pension Liability Total Balance at January 1, 2017 $ (212,211 ) $ (321 ) $ (1,794 ) $ (214,326 ) Other comprehensive income before reclassifications 5,823 234 — 6,057 Amounts reclassified out of accumulated other comprehensive loss — 146 — 146 Tax effects — (152 ) — (152 ) Other comprehensive income $ 5,823 $ 228 $ — $ 6,051 Balance at March 31, 2017 $ (206,388 ) $ (93 ) $ (1,794 ) $ (208,275 ) There were no reclassifications out of accumulated other comprehensive loss during the three months ended March 31, 2016 .

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION Total stock-based compensation cost charged to selling, general and administrative expenses for the three months ended March 31, 2017 and March 31, 2016 was $2.3 million and $2.1 million , respectively. The total income tax benefit recognized in the consolidated statements of operations from stock-based compensation was $0.8 million and $0.5 million for the three months ended March 31, 2017 and March 31, 2016 , respectively. Restricted Stock Awards The following information relates to restricted stock awards that have been granted to employees and directors under the Company's equity incentive plans (the "Plans"). The restricted stock awards are not transferable until vested and the restrictions generally lapse upon the achievement of continued employment over a three -to- five -year period or service as a director until the following annual meeting of shareholders. 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 and is amortized to expense over its vesting period. The following table summarizes information about restricted stock awards for the three months ended March 31, 2017 : Restricted Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2017 510,041 $ 52.65 Granted 22,794 $ 55.64 Vested (26,963 ) $ 54.45 Forfeited (29,218 ) $ 50.97 Balance at March 31, 2017 476,654 $ 52.80 As of March 31, 2017 , there was $18.5 million of total unrecognized compensation cost arising from restricted stock awards under the Company's Plans. This cost is expected to be recognized over a weighted average period of 3.0 years. The total fair value of restricted stock vested during the three months ended March 31, 2017 and March 31, 2016 was $1.5 million and $3.8 million , respectively. Performance Stock Awards The following information relates to performance stock awards that have been granted to employees under the Company's Plans. Performance stock awards are subject to performance criteria established by the compensation committee of the Company's board of directors prior to or at the date of grant. The vesting of the performance stock awards is based on achieving such targets typically based on revenue, Adjusted EBITDA margin, return on invested capital percentage and Total Recordable Incident Rate. In addition, performance stock awards include continued service conditions. The fair value of each performance stock award is based on the closing price of the Company's common stock on the date of grant and is amortized to expense over the service period if achievement of performance measures is considered probable. The following table summarizes information about performance stock awards for the three months ended March 31, 2017 : Performance Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2017 220,882 $ 54.69 Granted 588 $ 54.44 Vested (25,168 ) $ 54.84 Forfeited (13,398 ) $ 56.26 Balance at March 31, 2017 182,904 $ 54.69 As of March 31, 2017 , there was $1.0 million of total unrecognized compensation cost arising from unvested performance stock awards deemed probable of vesting under the Company's Plans. The total fair value of performance awards vested during the three months ended March 31, 2017 and March 31, 2016 was $1.4 million and $0.4 million , respectively. Common Stock Repurchases On March 13, 2015, the Company's board of directors authorized the repurchase of up to $300 million of the Company's common stock. During the three months ended March 31, 2017 , the Company repurchased and retired a total of 0.1 million shares of the Company's common stock for a total cost of $6.8 million . Through March 31, 2017 , the Company has repurchased and retired a total of 4.0 million shares of the Company's common stock for a total cost of $206.7 million under this program. As of March 31, 2017 , an additional $93.3 million remains available for repurchase of shares under the current authorized program.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal and Administrative Proceedings The Company and its subsidiaries are subject to legal proceedings and claims arising in the ordinary course of business. Actions filed against the Company arise from commercial and employment-related claims including alleged class actions related to sales practices and wage and hour claims. The plaintiffs in these actions may be seeking damages or injunctive relief or both. These actions are in various jurisdictions and stages of proceedings, and some are covered in part by insurance. In addition, the Company’s waste management services operations are regulated by federal, state, provincial and local laws enacted to regulate discharge of materials into the environment, remediation of contaminated soil and groundwater or otherwise protect the environment. This ongoing regulation results in the Company frequently becoming a party to legal or administrative proceedings involving all levels of governmental authorities and other interested parties. The issues involved in such proceedings generally relate to alleged violations of existing permits and licenses or alleged responsibility under federal or state Superfund laws to remediate contamination at properties owned either by the Company or by other parties (“third party sites”) to which either the Company or the prior owners of certain of the Company’s facilities shipped wastes. At March 31, 2017 and December 31, 2016 , the Company had recorded reserves of $21.9 million and $22.0 million , respectively, in the Company's financial statements for actual or probable liabilities related to the legal and administrative proceedings in which the Company was then involved, the principal of which are described below. At March 31, 2017 and December 31, 2016 , the Company also believed that it was reasonably possible that the amount of these potential liabilities could be as much as $1.7 million and $1.9 million more, respectively. The Company periodically adjusts the aggregate amount of these reserves when actual or probable liabilities are paid or otherwise discharged, new claims arise, or additional relevant information about existing or probable claims becomes available. As of March 31, 2017 and December 31, 2016 , the $21.9 million and $22.0 million , respectively, of reserves consisted of (i) $17.7 million and $18.2 million , respectively, related to pending legal or administrative proceedings, including Superfund liabilities, which were included in remedial liabilities on the consolidated balance sheets, and (ii) $4.2 million and $3.8 million , respectively, primarily related to federal, state and provincial enforcement actions, which were included in accrued expenses on the consolidated balance sheets. As of March 31, 2017 , the principal legal and administrative proceedings in which the Company was involved, or which had been terminated during 2017 , were as follows: Ville Mercier. In September 2002, the Company acquired the stock of a subsidiary (the "Mercier Subsidiary") which owns a hazardous waste incinerator in Ville Mercier, Quebec (the "Mercier Facility"). The property adjacent to the Mercier Facility, which is also owned by the Mercier Subsidiary, is now contaminated as a result of actions dating back to 1968, when the Government of Quebec issued to a company unrelated to the Mercier Subsidiary two permits to dump organic liquids into lagoons on the property. In 1999, Ville Mercier and three neighboring municipalities filed separate legal proceedings against the Mercier Subsidiary and the Government of Quebec. In 2012, the municipalities amended their existing statement of claim to seek $2.9 million (Cdn) in general damages and $10.0 million (Cdn) in punitive damages, plus interest and costs, as well as injunctive relief. Both the Government of Quebec and the Company have filed summary judgment motions against the municipalities. The parties are currently attempting to negotiate a resolution and hearings on the motions have been delayed. In September 2007, the Quebec Minister of Sustainable Development, Environment and Parks issued a Notice pursuant to Section 115.1 of the Environment Quality Act, superseding Notices issued in 1992, which are the subject of the pending litigation. The more recent Notice notifies the Mercier Subsidiary that, if the Mercier Subsidiary does not take certain remedial measures at the site, the Minister intends to undertake those measures at the site and claim direct and indirect costs related to such measures. The Company has accrued for costs expected to be incurred relative to the resolution of this matter and believes this matter will not have future material effect on its financial position or results of operations. Safety-Kleen Legal Proceedings. On December 28, 2012, the Company acquired Safety-Kleen, Inc. ("Safety-Kleen") and thereby became subject to the legal proceedings in which Safety-Kleen was a party on that date. In addition to certain Superfund proceedings in which Safety-Kleen has been named as a potentially responsible party as described below under “Superfund Proceedings,” the principal such legal proceedings involving Safety-Kleen which were outstanding as of March 31, 2017 were as follows: Product Liability Cases. Safety-Kleen has been named as a defendant in various lawsuits that are currently pending in various courts and jurisdictions throughout the United States, including approximately 58 proceedings (excluding cases which have been settled but not formally dismissed) as of March 31, 2017 , wherein persons claim personal injury resulting from the use of Safety-Kleen's parts cleaning equipment or cleaning products. These proceedings typically involve allegations that the solvent used in Safety-Kleen's parts cleaning equipment contains contaminants and/or that Safety-Kleen's recycling process does not effectively remove the contaminants that become entrained in the solvent during their use. In addition, certain claimants assert that Safety-Kleen failed to warn adequately the product user of potential risks, including an historic failure to warn that solvent contains trace amounts of toxic or hazardous substances such as benzene. Safety-Kleen maintains insurance that it believes will provide coverage for these product liability claims (over amounts accrued for self-insured retentions and deductibles in certain limited cases), except for punitive damages to the extent not insurable under state law or excluded from insurance coverage. Safety-Kleen also believes that these claims lack merit and has historically vigorously defended, and intends to continue to vigorously defend, itself and the safety of its products against all of these claims. Such matters are subject to many uncertainties and outcomes are not predictable with assurance. Consequently, Safety-Kleen is unable to ascertain the ultimate aggregate amount of monetary liability or financial impact with respect to these matters as of March 31, 2017 . From January 1, 2017 to March 31, 2017 , 9 product liability claims were settled or dismissed. Due to the nature of these claims and the related insurance, the Company did not incur any expense as Safety-Kleen's insurance provided coverage in full for all such claims. Safety-Kleen may be named in similar, additional lawsuits in the future, including claims for which insurance coverage may not be available. Superfund Proceedings The Company has been notified that either the Company (which, since December 28, 2012, includes Safety-Kleen) or the prior owners of certain of the Company's facilities for which the Company may have certain indemnification obligations have been identified as potentially responsible parties ("PRPs") or potential PRPs in connection with 129 sites which are subject to or are proposed to become subject to proceedings under federal or state Superfund laws. Of the 129 sites, three (including the BR Facility described below) involve facilities that are now owned or leased by the Company and 126 involve third party sites to which either the Company or the prior owners of certain of the Company’s facilities shipped wastes. Of the 126 third party sites, 33 are now settled, 16 are currently requiring expenditures on remediation and 77 are not currently requiring expenditures on remediation. In connection with each site, the Company has estimated the extent, if any, to which it may be subject, either directly or as a result of any indemnification obligations, for cleanup and remediation costs, related legal and consulting costs associated with PRP investigations, settlements, and related legal and administrative proceedings. The amount of such actual and potential liability is inherently difficult to estimate because of, among other relevant factors, uncertainties as to the legal liability (if any) of the Company or the prior owners of certain of the Company's facilities to contribute a portion of the cleanup costs, the assumptions that must be made in calculating the estimated cost and timing of remediation, the identification of other PRPs and their respective capability and obligation to contribute to remediation efforts, and the existence and legal standing of indemnification agreements (if any) with prior owners, which may either benefit the Company or subject the Company to potential indemnification obligations. The Company believes its potential liability could exceed $100,000 at 11 of the 126 third party sites. BR Facility. The Company acquired in 2002 a former hazardous waste incinerator and landfill in Baton Rouge (the "BR Facility"), for which operations had been previously discontinued by the prior owner. In September 2007, the EPA issued a special notice letter to the Company related to the Devil's Swamp Lake Site ("Devil's Swamp") in East Baton Rouge Parish, Louisiana. Devil's Swamp includes a lake located downstream of an outfall ditch where wastewater and storm water have been discharged, and Devil's Swamp is proposed to be included on the National Priorities List due to the presence of Contaminants of Concern ("COC") cited by the EPA. These COCs include substances of the kind found in wastewater and storm water discharged from the BR Facility in past operations. The EPA originally requested COC generators to submit a good faith offer to conduct a remedial investigation feasibility study directed towards the eventual remediation of the site. The Company is currently performing corrective actions at the BR Facility under an order issued by the Louisiana Department of Environmental Quality, and has begun conducting the remedial investigation and feasibility study under an order issued by the EPA. The Company cannot presently estimate the potential additional liability for the Devil's Swamp cleanup until a final remedy is selected by the EPA. Third Party Sites. Of the 126 third party sites at which the Company has been notified it is a PRP or potential PRP or may have indemnification obligations, Clean Harbors has an indemnification agreement at 11 of these sites with ChemWaste, a former subsidiary of Waste Management, Inc., and at six additional of these third party sites, Safety-Kleen has a similar indemnification agreement with McKesson Corporation. These agreements indemnify the Company (which now includes Safety-Kleen) with respect to any liability at the 17 sites for waste disposed prior to the Company's (or Safety-Kleen's) acquisition of the former subsidiaries of Waste Management and McKesson which had shipped wastes to those sites. Accordingly, Waste Management or McKesson are paying all costs of defending those subsidiaries in those 17 cases, including legal fees and settlement costs. However, there can be no guarantee that the Company's ultimate liabilities for those sites will not exceed the amount recorded or that indemnities applicable to any of these sites will be available to pay all or a portion of related costs. Except for the indemnification agreements which the Company holds from ChemWaste, McKesson and one other entity, the Company does not have an indemnity agreement with respect to any of the 126 third party sites discussed above. Federal, State and Provincial Enforcement Actions From time to time, the Company pays fines or penalties in regulatory proceedings relating primarily to waste treatment, storage or disposal facilities. As of March 31, 2017 and December 31, 2016 , there were four and five proceedings, respectively, for which the Company reasonably believes that the sanctions could equal or exceed $100,000 . The Company believes that the fines or other penalties in these or any of the other regulatory proceedings will, individually or in the aggregate, not have a material effect on its financial condition, results of operations or cash flows.

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Company records a tax provision or benefit on an interim basis using an estimated annual effective tax rate. This rate is applied to the current period ordinary income or loss to determine the income tax provision or benefit allocated to the interim period. Losses from jurisdictions for which no benefit can be recognized and the income tax effects of unusual or infrequent items are excluded from the estimated annual effective tax rate and are recognized in the impacted interim period. The estimated annual effective tax rate may be significantly impacted by projected earnings mix by tax jurisdiction. Adjustments to the estimated annual effective income tax rate are recognized in the period when such estimates are revised. The Company’s effective tax rate for the three months ended March 31, 2017 was (14.5)% compared to 10.9% for the same periods in 2016 . The variations in the effective income tax rates for the three months ended March 31, 2017 as compared to more customary relationships between pre-tax income and the provision for income taxes were primarily due to the Company not recognizing income tax benefits from current operating losses related to certain Canadian entities. As of both March 31, 2017 and December 31, 2016 , the Company had recorded $1.7 million of liabilities for unrecognized tax benefits and $0.3 million of interest. Due to expiring statute of limitation periods, the Company believes that total unrecognized tax benefits will decrease by $0.5 million within the next 12 months.

SEGMENT REPORTING

SEGMENT REPORTING	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
SEGMENT REPORTING	SEGMENT REPORTING Segment reporting is prepared on the same basis that the Company's chief executive officer, who is the Company's chief operating decision maker, manages its business, makes operating decisions and assesses performance. The Company's operations are managed in six operating segments: Technical Services, Industrial Services, Field Services, Safety-Kleen, Oil and Gas Field Services and Lodging Services. For purposes of segment disclosure the Industrial Services and Field Services operating segments have been aggregated into a single reportable segment based upon their similar economic and other characteristics, and the Oil and Gas Field Services and Lodging Services operating segments have been combined as they do not meet the quantitative thresholds for separate presentation. Third-party revenue is revenue billed to outside customers by a particular segment. Direct revenue is revenue allocated to the segment providing the product or service. Intersegment revenues represent the sharing of third-party revenues among the segments based on products and services provided by each segment as if the products and services were sold directly to the third-party. The intersegment revenues are shown net. The negative intersegment revenues are due to more transfers out of customer revenues to other segments than transfers in of customer revenues from other segments. The operations not managed through the Company’s operating segments described above are recorded as “Corporate Items.” Corporate Items revenues consist of two different operations for which the revenues are insignificant. Corporate Items cost of revenues represents certain central services that are not allocated to the Company's operating segments for internal reporting purposes. Corporate Items selling, general and administrative expenses include typical corporate items such as legal, accounting and other items of a general corporate nature that are not allocated to the Company’s operating segments. The following table reconciles third party revenues to direct revenues for the three months ended March 31, 2017 and 2016 (in thousands): For the Three Months Ended March 31, 2017 For the Three Months Ended March 31, 2016 Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Technical Services $ 230,218 $ 40,044 $ 722 $ 270,984 $ 219,105 $ 34,844 $ 388 $ 254,337 Industrial and Field Services 133,557 (8,359 ) 104 125,302 130,187 (6,675 ) (13 ) 123,499 Safety-Kleen 292,901 (32,069 ) 3 260,835 246,961 (28,521 ) 366 218,806 Oil, Gas and Lodging Services 32,132 384 94 32,610 39,051 352 104 39,507 Corporate Items 133 — (923 ) (790 ) 779 — (845 ) (66 ) Total $ 688,941 $ — $ — $ 688,941 $ 636,083 $ — $ — $ 636,083 The primary financial measure by which the Company evaluates the performance of its segments is Adjusted EBITDA which consists of net loss plus accretion of environmental liabilities, depreciation and amortization, net interest expense, provision (benefit) for income taxes and excludes other expense, net. Transactions between the segments are accounted for at the Company’s best estimate based on similar transactions with outside customers. The following table presents Adjusted EBITDA information used by management by reported segment (in thousands): For the Three Months Ended March 31, 2017 2016 Adjusted EBITDA: Technical Services $ 58,488 $ 60,398 Industrial and Field Services 1,913 433 Safety-Kleen 52,368 40,055 Oil, Gas and Lodging Services (211 ) 1,310 Corporate Items (32,423 ) (34,876 ) Total $ 80,135 $ 67,320 Reconciliation to Consolidated Statements of Operations: Accretion of environmental liabilities 2,290 2,505 Depreciation and amortization 72,412 68,902 Income (loss) from operations 5,433 (4,087 ) Other expense 1,549 350 Interest expense, net of interest income 22,576 18,980 Loss before provision (benefit) for income taxes $ (18,692 ) $ (23,417 ) The following table presents certain assets by reportable segment and in the aggregate (in thousands): March 31, 2017 Technical Industrial and Field Safety-Kleen Oil, Gas and Lodging Corporate Totals Property, plant and equipment, net $ 521,726 $ 245,250 $ 589,782 $ 173,347 $ 79,385 $ 1,609,490 Goodwill 61,158 108,131 300,571 — — 469,860 Permits and other intangibles, net 77,131 17,973 386,125 9,723 — 490,952 Total assets $ 856,324 $ 446,757 $ 1,477,851 $ 246,910 $ 617,811 $ 3,645,653 December 31, 2016 Technical Industrial and Field Safety-Kleen Oil, Gas and Lodging Corporate Totals Property, plant and equipment, net $ 521,134 $ 245,143 $ 584,647 $ 182,038 $ 78,865 $ 1,611,827 Goodwill 61,116 107,968 296,070 — — 465,154 Permits and other intangibles, net 78,625 17,817 391,390 10,889 — 498,721 Total assets $ 862,957 $ 446,826 $ 1,474,755 $ 253,242 $ 644,140 $ 3,681,920 The following table presents total assets by geographical area (in thousands): March 31, 2017 December 31, 2016 United States $ 2,947,064 $ 2,960,337 Canada 698,589 721,583 Total $ 3,645,653 $ 3,681,920

GUARANTOR AND NON-GUARANTOR SUB

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION	3 Months Ended
	Mar. 31, 2017
Guarantor and Non-Guarantor Subsidiaries Financial Information [Abstract]
GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION	GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION The 2020 Notes and the 2021 Notes (collectively, the "Notes") are guaranteed by substantially all of the Company’s subsidiaries organized in the United States. Each guarantor for the Notes is a 100% owned subsidiary of Clean Harbors, Inc. and its guarantee is both full and unconditional and joint and several. The guarantees are, however, subject to customary release provisions under which, in particular, the guarantee of any domestic restricted subsidiary will be released if the Company sells such subsidiary to an unrelated third party in accordance with the terms of the indentures which govern the Notes. The Notes are not guaranteed by the Company’s subsidiaries organized outside the United States. The following supplemental condensed consolidating financial information for the parent company, the guarantor subsidiaries and the non-guarantor subsidiaries, respectively, is presented in conformity with the requirements of Rule 3-10 of SEC Regulation S-X (“Rule 3-10”). Following is the condensed consolidating balance sheet at March 31, 2017 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 51,726 $ 139,160 $ 106,480 $ — $ 297,366 Intercompany receivables 209,410 396,286 40,235 (645,931 ) — Accounts receivable, net — 400,764 79,280 — 480,044 Other current assets 1,033 235,715 59,592 (11,979 ) 284,361 Property, plant and equipment, net — 1,214,176 395,314 — 1,609,490 Investments in subsidiaries 2,849,584 563,331 — (3,412,915 ) — Intercompany debt receivable — 87,215 24,701 (111,916 ) — Goodwill — 417,224 52,636 — 469,860 Permits and other intangibles, net — 429,311 61,641 — 490,952 Other long-term assets 2,421 7,661 4,566 (1,068 ) 13,580 Total assets $ 3,114,174 $ 3,890,843 $ 824,445 $ (4,183,809 ) $ 3,645,653 Liabilities and Stockholders’ Equity: Current liabilities $ 22,063 $ 356,914 $ 121,583 $ (11,979 ) $ 488,581 Intercompany payables 390,812 245,871 9,248 (645,931 ) — Closure, post-closure and remedial liabilities, net — 148,992 16,397 — 165,389 Long-term obligations 1,633,968 — — — 1,633,968 Intercompany debt payable 3,701 21,000 87,215 (111,916 ) — Other long-term liabilities — 276,118 19,035 (1,068 ) 294,085 Total liabilities 2,050,544 1,048,895 253,478 (770,894 ) 2,582,023 Stockholders’ equity 1,063,630 2,841,948 570,967 (3,412,915 ) 1,063,630 Total liabilities and stockholders’ equity $ 3,114,174 $ 3,890,843 $ 824,445 $ (4,183,809 ) $ 3,645,653 Following is the condensed consolidating balance sheet at December 31, 2016 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 51,417 $ 155,943 $ 99,637 $ — $ 306,997 Intercompany receivables 200,337 354,836 49,055 (604,228 ) — Accounts receivables, net — 417,029 79,197 — 496,226 Other current assets 3,096 234,408 69,257 (17,113 ) 289,648 Property, plant and equipment, net — 1,211,210 400,617 — 1,611,827 Investments in subsidiaries 2,851,571 580,124 — (3,431,695 ) — Intercompany debt receivable — 86,409 24,701 (111,110 ) — Goodwill — 412,638 52,516 — 465,154 Permits and other intangibles, net — 435,594 63,127 — 498,721 Other long-term assets 2,446 7,582 4,387 (1,068 ) 13,347 Total assets $ 3,108,867 $ 3,895,773 $ 842,494 $ (4,165,214 ) $ 3,681,920 Liabilities and Stockholders’ Equity: Current liabilities $ 21,805 $ 366,831 $ 133,145 $ (17,113 ) $ 504,668 Intercompany payables 365,848 237,058 1,322 (604,228 ) — Closure, post-closure and remedial liabilities, net — 150,682 15,640 — 166,322 Long-term obligations 1,633,272 — — — 1,633,272 Intercompany debt payable 3,701 21,000 86,409 (111,110 ) — Other long-term liabilities — 275,649 18,836 (1,068 ) 293,417 Total liabilities 2,024,626 1,051,220 255,352 (733,519 ) 2,597,679 Stockholders’ equity 1,084,241 2,844,553 587,142 (3,431,695 ) 1,084,241 Total liabilities and stockholders’ equity $ 3,108,867 $ 3,895,773 $ 842,494 $ (4,165,214 ) $ 3,681,920 Following is the consolidating statement of operations for the three months ended March 31, 2017 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 443,305 $ 131,071 $ (14,162 ) $ 560,214 Product revenues — 116,650 15,331 (3,254 ) 128,727 Total revenues — 559,955 146,402 (17,416 ) 688,941 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 294,145 111,104 (14,162 ) 391,087 Product cost of revenues — 96,505 12,247 (3,254 ) 105,498 Total cost of revenues — 390,650 123,351 (17,416 ) 496,585 Selling, general and administrative expenses 24 92,171 20,026 — 112,221 Accretion of environmental liabilities — 2,055 235 — 2,290 Depreciation and amortization — 51,900 20,512 — 72,412 (Loss) income from operations (24 ) 23,179 (17,722 ) — 5,433 Other expense (146 ) (1,389 ) (14 ) — (1,549 ) Interest (expense) income (22,659 ) 119 (36 ) — (22,576 ) Equity in earnings of subsidiaries, net of taxes (7,637 ) (21,824 ) — 29,461 — Intercompany interest income (expense) — 1,297 (1,297 ) — — (Loss) income before (benefit) provision for income taxes (30,466 ) 1,382 (19,069 ) 29,461 (18,692 ) (Benefit) provision for income taxes (9,073 ) 9,637 2,137 — 2,701 Net loss (21,393 ) (8,255 ) (21,206 ) 29,461 (21,393 ) Other comprehensive income 6,051 6,051 5,032 (11,083 ) 6,051 Comprehensive loss $ (15,342 ) $ (2,204 ) $ (16,174 ) $ 18,378 $ (15,342 ) Following is the consolidating statement of operations for the three months ended March 31, 2016 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 428,477 $ 114,023 $ (12,269 ) $ 530,231 Product revenues — 89,588 18,713 (2,449 ) 105,852 Total revenues — 518,065 132,736 (14,718 ) 636,083 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 282,964 103,291 (12,269 ) 373,986 Product cost of revenues — 79,354 13,388 (2,449 ) 90,293 Total cost of revenues — 362,318 116,679 (14,718 ) 464,279 Selling, general and administrative expenses 24 80,655 23,805 — 104,484 Accretion of environmental liabilities — 2,290 215 — 2,505 Depreciation and amortization — 48,695 20,207 — 68,902 (Loss) income from operations (24 ) 24,107 (28,170 ) — (4,087 ) Other expense — (88 ) (262 ) — (350 ) Interest (expense) income (20,143 ) 1,111 52 — (18,980 ) Equity in earnings of subsidiaries, net of taxes (8,771 ) (26,495 ) — 35,266 — Intercompany interest income (expense) — 5,159 (5,159 ) — — (Loss) income before (benefit) provision for income taxes (28,938 ) 3,794 (33,539 ) 35,266 (23,417 ) (Benefit) provision for income taxes (8,067 ) 12,565 (7,044 ) — (2,546 ) Net loss (20,871 ) (8,771 ) (26,495 ) 35,266 (20,871 ) Other comprehensive income 45,837 45,837 28,927 (74,764 ) 45,837 Comprehensive income $ 24,966 $ 37,066 $ 2,432 $ (39,498 ) $ 24,966 Following is the condensed consolidating statement of cash flows for the three months ended March 31, 2017 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash (used in) from operating activities $ (1,663 ) $ 41,144 $ 17,638 $ — $ 57,119 Cash flows from (used in) investing activities: Additions to property, plant and equipment — (33,136 ) (9,326 ) — (42,462 ) Proceeds from sales of fixed assets — 664 366 — 1,030 Acquisitions, net of cash acquired — (11,946 ) — — (11,946 ) Proceeds on sale of business 1,837 — 181 — 2,018 Costs to obtain or renew permits — (573 ) (178 ) — (751 ) Proceeds from sale of investments 243 — — — 243 Intercompany — (7,771 ) — 7,771 — Net cash from (used in) investing activities 2,080 (52,762 ) (8,957 ) 7,771 (51,868 ) Cash flows used in financing activities: Change in uncashed checks — (5,165 ) (2,392 ) — (7,557 ) Proceeds from exercise of stock options 46 — — — 46 Issuance of restricted shares, net of shares remitted (1,021 ) — — — (1,021 ) Repurchases of common stock (6,796 ) — — — (6,796 ) Deferred financing costs paid (108 ) — — — (108 ) Intercompany 7,771 — — (7,771 ) — Net cash used in financing activities (108 ) (5,165 ) (2,392 ) (7,771 ) (15,436 ) Effect of exchange rate change on cash — — 554 — 554 Increase (decrease) in cash and cash equivalents 309 (16,783 ) 6,843 — (9,631 ) Cash and cash equivalents, beginning of period 51,417 155,943 99,637 — 306,997 Cash and cash equivalents, end of period $ 51,726 $ 139,160 $ 106,480 $ — $ 297,366 Following is the condensed consolidating statement of cash flows for the three months ended March 31, 2016 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash from (used in) operating activities $ 47,201 $ (3,361 ) $ (4,551 ) $ — $ 39,289 Cash flows used in investing activities: Additions to property, plant and equipment — (64,754 ) (11,027 ) — (75,781 ) Proceeds from sales of fixed assets — 277 996 — 1,273 Acquisitions, net of cash acquired — (34,993 ) — — (34,993 ) Costs to obtain or renew permits — (465 ) (47 ) — (512 ) Intercompany — (6,423 ) — 6,423 — Investment in subsidiaries (250,625 ) — — 250,625 — Net cash used in investing activities (250,625 ) (106,358 ) (10,078 ) 257,048 (110,013 ) Cash flows from (used in) financing activities: Change in uncashed checks — (4,529 ) (689 ) — (5,218 ) Issuance of restricted shares, net of shares remitted (1,425 ) — — — (1,425 ) Repurchases of common stock (4,998 ) — — — (4,998 ) Deferred financing costs paid (2,190 ) — — — (2,190 ) Issuance of senior secured notes, including premium 250,625 250,625 — (250,625 ) 250,625 Intercompany 6,423 — — (6,423 ) — Net cash from (used in) financing activities 248,435 246,096 (689 ) (257,048 ) 236,794 Effect of exchange rate change on cash — — 4,567 — 4,567 Increase (decrease) in cash and cash equivalents 45,011 136,377 (10,751 ) — 170,637 Cash and cash equivalents, beginning of period 11,017 83,479 90,212 — 184,708 Cash and cash equivalents, end of period $ 56,028 $ 219,856 $ 79,461 $ — $ 355,345

SIGNIFICANT ACCOUNTING POLICI29

SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Reclassifications	As disclosed in the Company's Annual Report on Form 10-K for the year ended December 31, 2016 , in the fourth quarter of 2016 the Company changed the manner in which it manages its business, makes operating decisions and assesses the Company's performance. The Company's operations are now managed in six operating segments: Technical Services, Industrial Services, Field Services, Safety-Kleen, Oil and Gas Field Services and Lodging Services. For purposes of segment disclosure the Industrial Services and Field Services operating segments have been aggregated into a single reportable segment based upon their similar economic and other characteristics, and the Oil and Gas Field Services and Lodging Services operating segments have been combined as they do not meet the quantitative thresholds for separate presentation. The amounts presented for the three months ended March 31, 2016 have been recast to reflect the impact of such changes. These reclassifications and adjustments had no effect on consolidated net loss, comprehensive (loss) income, cash flows or stockholders' equity for any of the periods presented.
Recent Accounting Pronouncements	In July 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-11, Inventory (Topic 330). The amendment provides guidance regarding the measurement of inventory. Entities should measure inventory within the scope of this update at the lower of cost and net realizable value. The adoption of ASU 2015-11 was applied prospectively and as of January 1, 2017 did not have an impact on the Company's consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendment simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. Stock-based compensation excess tax benefits or deficiencies are now reflected in the Consolidated Statements of Operations as a component of the provision for income taxes, whereas they previously were recognized in equity. Additionally, the Consolidated Statements of Cash Flows now include excess tax benefits as an operating activity. Previously, income tax benefits at settlement of an award were reported as a reduction to operating cash flows and an increase to financing cash flows to the extent that those benefits exceeded the income tax benefits reported in earnings during the award's vesting period. The Company has elected to apply that change in cash flow classification on a prospective basis, leaving previously reported net cash from operating activities and net cash from financing activities in the accompanying Consolidated Statement of Cash Flows for the period ended March 31, 2016 unchanged. Finally, the Company has elected to account for forfeitures as they occur, rather than estimate expected forfeitures. As a result of the adoption of this update, the Company recorded a cumulative-effect adjustment that reduced beginning retained earnings by $ 0.5 million , net of tax. Standard to be implemented In May 2014, FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) . ASU 2014-09 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and supersedes most current revenue recognition guidance, including industry-specific guidance. In August 2015, FASB issued ASU 2015-14 which deferred the effective date of ASU 2014-09 for all entities by one year. In March 2016, FASB issued ASU 2016-08, which reduces the potential for diversity in practice arising from inconsistent application of the principal versus agent guidance, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In April 2016, FASB issued ASU 2016-10, which reduces the potential for diversity in initial application, as well as the cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In May 2016, FASB issued ASU 2016-12, which provided narrow scope improvements and practical expedients on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. ASU 2014-09 is currently effective for annual reporting periods (including interim reporting periods within those periods) beginning after December 15, 2017. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the cumulative catch-up transition method). The Company expects that it will adopt ASU 2014‑09 beginning in the first quarter of 2018 and continues its evaluation of the impact of the new standard on its accounting policies, processes, and system requirements. The Company has assigned internal resources to assist in this implementation project and believes that the project is progressing timely. A final decision regarding the adoption method has not been finalized at this time. The Company’s final determination will depend on a number of factors, such as the significance of the impact of the new standard on its financial results, system readiness, and its ability to accumulate and analyze the information necessary to assess the impact on prior period financial statements, as necessary. In February 2017, the FASB issued ASU 2017-05, Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets . The amendments in this Update are meant to clarify the scope of ASC Subtopic 610-20, Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets and to add guidance for partial sales of nonfinancial assets. The amendments in this Update should be applied using a full retrospective method or a modified retrospective method and are effective at the same time as ASU 2014-09. Further, the Company is required to adopt ASU 2017-05 at the same time that it adopts the guidance in ASU 2014-09. Adoption is not expected to have a material impact on the Company's consolidated financial statements.

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The components and preliminary allocation of the purchase price consist of the following amounts (in thousands): At Acquisition Dates As Reported Measurement Period Adjustments At Acquisition Dates As Reported Accounts receivable $ 15,767 $ 629 $ 16,396 Inventories and supplies 12,515 173 12,688 Prepaid expenses and other current assets 777 (25 ) 752 Property, plant and equipment 143,025 625 143,650 Permits and other intangibles 28,856 — 28,856 Current liabilities (20,258 ) 392 (19,866 ) Closure and post-closure liabilities (2,408 ) (596 ) (3,004 ) Remedial liabilities, less current portion (2,041 ) 16 (2,025 ) Deferred taxes, unrecognized tax benefits and other long-term liabilities (17,019 ) (456 ) (17,475 ) Total identifiable net assets 159,214 758 159,972 Goodwill 45,791 (731 ) 45,060 Total purchase price, net of cash acquired $ 205,005 $ 27 $ 205,032

DISPOSITION OF BUSINESS (Tables

DISPOSITION OF BUSINESS (Tables)	3 Months Ended
	Mar. 31, 2017
Discontinued Operations and Disposal Groups [Abstract]
Disposition of Business	The following table presents the loss before benefit for income taxes attributable to the Catalyst Services business included in the Company's consolidated results of operations for three months ended March 31, 2016 (in thousands): Three Months Ended March 31, 2016 Loss before benefit for income taxes 1,099

INVENTORIES AND SUPPLIES (Table

INVENTORIES AND SUPPLIES (Tables)	3 Months Ended
	Mar. 31, 2017
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventories and supplies consisted of the following (in thousands): March 31, 2017 December 31, 2016 Oil and oil products $ 55,872 $ 52,158 Supplies and drums 91,210 90,610 Solvent and solutions 8,865 8,566 Modular camp accommodations 14,859 15,255 Other 11,232 11,839 Total inventories and supplies $ 182,038 $ 178,428

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment consisted of the following (in thousands): March 31, 2017 December 31, 2016 Land $ 122,184 $ 120,575 Asset retirement costs (non-landfill) 15,173 14,567 Landfill assets 140,518 139,708 Buildings and improvements 406,562 373,160 Camp equipment 151,561 152,740 Vehicles 558,175 541,022 Equipment 1,591,511 1,483,736 Furniture and fixtures 5,507 5,492 Construction in progress 42,305 146,904 3,033,496 2,977,904 Less - accumulated depreciation and amortization 1,424,006 1,366,077 Total property, plant and equipment, net $ 1,609,490 $ 1,611,827

GOODWILL AND OTHER INTANGIBLE34

GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes to goodwill	The changes in goodwill for the three months ended March 31, 2017 were as follows (in thousands): Technical Services Industrial & Field Services Safety-Kleen Oil, Gas and Lodging Services Totals Balance at January 1, 2017 $ 61,116 $ 107,968 $ 296,070 $ — $ 465,154 Increase from current period acquisitions — — 4,938 — 4,938 Measurement period adjustments from prior period acquisitions — — (731 ) — (731 ) Foreign currency translation and other 42 163 294 — 499 Balance at March 31, 2017 $ 61,158 $ 108,131 $ 300,571 $ — $ 469,860
Summary of indefinite-lived intangible assets	As of March 31, 2017 and December 31, 2016 , the Company's total finite-lived and indefinite-lived intangible assets consisted of the following (in thousands): March 31, 2017 December 31, 2016 Cost Accumulated Net Weighted Cost Accumulated Net Weighted Permits $ 172,666 $ 69,151 $ 103,515 19.8 $ 171,637 $ 67,301 $ 104,336 18.9 Customer and supplier relationships 394,086 134,599 259,487 11.9 393,426 127,462 265,964 12.2 Other intangible assets 34,463 29,228 5,235 7.1 34,254 28,456 5,798 7.1 Total amortizable permits and other intangible assets 601,215 232,978 368,237 14.9 599,317 223,219 376,098 13.9 Trademarks and trade names 122,715 — 122,715 Indefinite 122,623 — 122,623 Indefinite Total permits and other intangible assets $ 723,930 $ 232,978 $ 490,952 $ 721,940 $ 223,219 $ 498,721
Schedule of finite-Lived intangible assets	As of March 31, 2017 and December 31, 2016 , the Company's total finite-lived and indefinite-lived intangible assets consisted of the following (in thousands): March 31, 2017 December 31, 2016 Cost Accumulated Net Weighted Cost Accumulated Net Weighted Permits $ 172,666 $ 69,151 $ 103,515 19.8 $ 171,637 $ 67,301 $ 104,336 18.9 Customer and supplier relationships 394,086 134,599 259,487 11.9 393,426 127,462 265,964 12.2 Other intangible assets 34,463 29,228 5,235 7.1 34,254 28,456 5,798 7.1 Total amortizable permits and other intangible assets 601,215 232,978 368,237 14.9 599,317 223,219 376,098 13.9 Trademarks and trade names 122,715 — 122,715 Indefinite 122,623 — 122,623 Indefinite Total permits and other intangible assets $ 723,930 $ 232,978 $ 490,952 $ 721,940 $ 223,219 $ 498,721
Schedule of expected amortization for the net carrying amount of finite lived intangible assets	The expected amortization of the net carrying amount of finite-lived intangible assets at March 31, 2017 was as follows (in thousands): Years Ending December 31, Expected Amortization 2017 (nine months) $ 27,392 2018 34,072 2019 31,275 2020 29,067 2021 26,640 Thereafter 219,791 $ 368,237

ACCRUED EXPENSES (Tables)

ACCRUED EXPENSES (Tables)	3 Months Ended
	Mar. 31, 2017
Payables and Accruals [Abstract]
Accrued expenses	Accrued expenses consisted of the following at March 31, 2017 and December 31, 2016 (in thousands): March 31, 2017 December 31, 2016 Insurance $ 56,603 $ 63,061 Interest 21,770 21,536 Accrued compensation and benefits 41,109 34,641 Income, real estate, sales and other taxes 29,814 35,083 Other 34,661 36,400 $ 183,957 $ 190,721

CLOSURE AND POST-CLOSURE LIAB36

CLOSURE AND POST-CLOSURE LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2017
Asset Retirement Obligation Disclosure [Abstract]
Schedule of closure and post-closure liabilities	The changes to closure and post-closure liabilities (also referred to as “asset retirement obligations”) from January 1, 2017 through March 31, 2017 were as follows (in thousands): Landfill Non-Landfill Total Balance at January 1, 2017 $ 30,630 $ 27,701 $ 58,331 Measurement period adjustments from prior period acquisitions — 596 596 New asset retirement obligations 431 — 431 Accretion 534 623 1,157 Changes in estimates recorded to statement of operations — (6 ) (6 ) Expenditures (119 ) (73 ) (192 ) Currency translation and other 20 14 34 Balance at March 31, 2017 $ 31,496 $ 28,855 $ 60,351

REMEDIAL LIABILITIES (Tables)

REMEDIAL LIABILITIES (Tables)	3 Months Ended
	Mar. 31, 2017
Environmental Remediation Obligations [Abstract]
Changes to remedial liabilities	The changes to remedial liabilities for the three months ended March 31, 2017 were as follows (in thousands): Remedial Liabilities for Landfill Sites Remedial Liabilities for Inactive Sites Remedial Liabilities (Including Superfund) for Non-Landfill Operations Total Balance at January 1, 2017 $ 1,777 $ 64,151 $ 62,079 $ 128,007 Measurement period adjustments from prior period acquisitions — — (16 ) (16 ) Accretion 21 615 497 1,133 Changes in estimates recorded to statement of operations (38 ) (94 ) 240 108 Expenditures (7 ) (720 ) (2,019 ) (2,746 ) Currency translation and other — 8 113 121 Balance at March 31, 2017 $ 1,753 $ 63,960 $ 60,894 $ 126,607

FINANCING ARRANGEMENTS (Tables)

FINANCING ARRANGEMENTS (Tables)	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Summary of the entity's financial arrangements	The following table is a summary of the Company’s financing arrangements (in thousands): March 31, 2017 December 31, 2016 Senior unsecured notes, at 5.25%, due August 1, 2020 ("2020 Notes") $ 800,000 $ 800,000 Senior unsecured notes, at 5.125%, due June 1, 2021 ("2021 Notes") 845,000 845,000 Long-term obligations, at par $ 1,645,000 $ 1,645,000 Unamortized debt issuance costs and premium, net (11,032 ) (11,728 ) Long-term obligations, at carrying value $ 1,633,968 $ 1,633,272

LOSS PER SHARE (Tables)

LOSS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Reconciliation of basic and diluted earnings per share computations	The following are computations of basic and diluted loss per share (in thousands except for per share amounts): Three Months Ended March 31, 2017 2016 Numerator for basic and diluted loss per share: Net loss $ (21,393 ) $ (20,871 ) Denominator: Basic shares outstanding 57,262 57,617 Dilutive effect of equity-based compensation awards — — Dilutive shares outstanding 57,262 57,617 Basic loss per share: $ (0.37 ) $ (0.36 ) Diluted loss per share: $ (0.37 ) $ (0.36 )

ACCUMULATED OTHER COMPREHENSI40

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Schedule of accumulated other comprehensive loss	The changes in accumulated other comprehensive loss by component and related tax effects for the three months ended March 31, 2017 were as follows (in thousands): Foreign Currency Translation Unrealized Gains on Available-For-Sale Securities Unfunded Pension Liability Total Balance at January 1, 2017 $ (212,211 ) $ (321 ) $ (1,794 ) $ (214,326 ) Other comprehensive income before reclassifications 5,823 234 — 6,057 Amounts reclassified out of accumulated other comprehensive loss — 146 — 146 Tax effects — (152 ) — (152 ) Other comprehensive income $ 5,823 $ 228 $ — $ 6,051 Balance at March 31, 2017 $ (206,388 ) $ (93 ) $ (1,794 ) $ (208,275 )

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of restricted stock awards	The following table summarizes information about restricted stock awards for the three months ended March 31, 2017 : Restricted Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2017 510,041 $ 52.65 Granted 22,794 $ 55.64 Vested (26,963 ) $ 54.45 Forfeited (29,218 ) $ 50.97 Balance at March 31, 2017 476,654 $ 52.80
Summary of performance stock awards	The following table summarizes information about performance stock awards for the three months ended March 31, 2017 : Performance Stock Number of Shares Weighted Average Grant-Date Fair Value Balance at January 1, 2017 220,882 $ 54.69 Granted 588 $ 54.44 Vested (25,168 ) $ 54.84 Forfeited (13,398 ) $ 56.26 Balance at March 31, 2017 182,904 $ 54.69

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Reconciliation of third party revenues to direct revenues	The following table reconciles third party revenues to direct revenues for the three months ended March 31, 2017 and 2016 (in thousands): For the Three Months Ended March 31, 2017 For the Three Months Ended March 31, 2016 Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Third party revenues Intersegment revenues, net Corporate Items, net Direct revenues Technical Services $ 230,218 $ 40,044 $ 722 $ 270,984 $ 219,105 $ 34,844 $ 388 $ 254,337 Industrial and Field Services 133,557 (8,359 ) 104 125,302 130,187 (6,675 ) (13 ) 123,499 Safety-Kleen 292,901 (32,069 ) 3 260,835 246,961 (28,521 ) 366 218,806 Oil, Gas and Lodging Services 32,132 384 94 32,610 39,051 352 104 39,507 Corporate Items 133 — (923 ) (790 ) 779 — (845 ) (66 ) Total $ 688,941 $ — $ — $ 688,941 $ 636,083 $ — $ — $ 636,083
Reconciliation to consolidated statements of income from adjusted EBITDA	The following table presents Adjusted EBITDA information used by management by reported segment (in thousands): For the Three Months Ended March 31, 2017 2016 Adjusted EBITDA: Technical Services $ 58,488 $ 60,398 Industrial and Field Services 1,913 433 Safety-Kleen 52,368 40,055 Oil, Gas and Lodging Services (211 ) 1,310 Corporate Items (32,423 ) (34,876 ) Total $ 80,135 $ 67,320 Reconciliation to Consolidated Statements of Operations: Accretion of environmental liabilities 2,290 2,505 Depreciation and amortization 72,412 68,902 Income (loss) from operations 5,433 (4,087 ) Other expense 1,549 350 Interest expense, net of interest income 22,576 18,980 Loss before provision (benefit) for income taxes $ (18,692 ) $ (23,417 )
PP&E, intangible assets and total assets by segment	The following table presents certain assets by reportable segment and in the aggregate (in thousands): March 31, 2017 Technical Industrial and Field Safety-Kleen Oil, Gas and Lodging Corporate Totals Property, plant and equipment, net $ 521,726 $ 245,250 $ 589,782 $ 173,347 $ 79,385 $ 1,609,490 Goodwill 61,158 108,131 300,571 — — 469,860 Permits and other intangibles, net 77,131 17,973 386,125 9,723 — 490,952 Total assets $ 856,324 $ 446,757 $ 1,477,851 $ 246,910 $ 617,811 $ 3,645,653 December 31, 2016 Technical Industrial and Field Safety-Kleen Oil, Gas and Lodging Corporate Totals Property, plant and equipment, net $ 521,134 $ 245,143 $ 584,647 $ 182,038 $ 78,865 $ 1,611,827 Goodwill 61,116 107,968 296,070 — — 465,154 Permits and other intangibles, net 78,625 17,817 391,390 10,889 — 498,721 Total assets $ 862,957 $ 446,826 $ 1,474,755 $ 253,242 $ 644,140 $ 3,681,920
Total assets by geographical area	The following table presents total assets by geographical area (in thousands): March 31, 2017 December 31, 2016 United States $ 2,947,064 $ 2,960,337 Canada 698,589 721,583 Total $ 3,645,653 $ 3,681,920

GUARANTOR AND NON-GUARANTOR S43

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2017
Guarantor and Non-Guarantor Subsidiaries Financial Information [Abstract]
Schedule of condensed consolidating balance sheet	Following is the condensed consolidating balance sheet at March 31, 2017 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 51,726 $ 139,160 $ 106,480 $ — $ 297,366 Intercompany receivables 209,410 396,286 40,235 (645,931 ) — Accounts receivable, net — 400,764 79,280 — 480,044 Other current assets 1,033 235,715 59,592 (11,979 ) 284,361 Property, plant and equipment, net — 1,214,176 395,314 — 1,609,490 Investments in subsidiaries 2,849,584 563,331 — (3,412,915 ) — Intercompany debt receivable — 87,215 24,701 (111,916 ) — Goodwill — 417,224 52,636 — 469,860 Permits and other intangibles, net — 429,311 61,641 — 490,952 Other long-term assets 2,421 7,661 4,566 (1,068 ) 13,580 Total assets $ 3,114,174 $ 3,890,843 $ 824,445 $ (4,183,809 ) $ 3,645,653 Liabilities and Stockholders’ Equity: Current liabilities $ 22,063 $ 356,914 $ 121,583 $ (11,979 ) $ 488,581 Intercompany payables 390,812 245,871 9,248 (645,931 ) — Closure, post-closure and remedial liabilities, net — 148,992 16,397 — 165,389 Long-term obligations 1,633,968 — — — 1,633,968 Intercompany debt payable 3,701 21,000 87,215 (111,916 ) — Other long-term liabilities — 276,118 19,035 (1,068 ) 294,085 Total liabilities 2,050,544 1,048,895 253,478 (770,894 ) 2,582,023 Stockholders’ equity 1,063,630 2,841,948 570,967 (3,412,915 ) 1,063,630 Total liabilities and stockholders’ equity $ 3,114,174 $ 3,890,843 $ 824,445 $ (4,183,809 ) $ 3,645,653 Following is the condensed consolidating balance sheet at December 31, 2016 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Assets: Cash and cash equivalents $ 51,417 $ 155,943 $ 99,637 $ — $ 306,997 Intercompany receivables 200,337 354,836 49,055 (604,228 ) — Accounts receivables, net — 417,029 79,197 — 496,226 Other current assets 3,096 234,408 69,257 (17,113 ) 289,648 Property, plant and equipment, net — 1,211,210 400,617 — 1,611,827 Investments in subsidiaries 2,851,571 580,124 — (3,431,695 ) — Intercompany debt receivable — 86,409 24,701 (111,110 ) — Goodwill — 412,638 52,516 — 465,154 Permits and other intangibles, net — 435,594 63,127 — 498,721 Other long-term assets 2,446 7,582 4,387 (1,068 ) 13,347 Total assets $ 3,108,867 $ 3,895,773 $ 842,494 $ (4,165,214 ) $ 3,681,920 Liabilities and Stockholders’ Equity: Current liabilities $ 21,805 $ 366,831 $ 133,145 $ (17,113 ) $ 504,668 Intercompany payables 365,848 237,058 1,322 (604,228 ) — Closure, post-closure and remedial liabilities, net — 150,682 15,640 — 166,322 Long-term obligations 1,633,272 — — — 1,633,272 Intercompany debt payable 3,701 21,000 86,409 (111,110 ) — Other long-term liabilities — 275,649 18,836 (1,068 ) 293,417 Total liabilities 2,024,626 1,051,220 255,352 (733,519 ) 2,597,679 Stockholders’ equity 1,084,241 2,844,553 587,142 (3,431,695 ) 1,084,241 Total liabilities and stockholders’ equity $ 3,108,867 $ 3,895,773 $ 842,494 $ (4,165,214 ) $ 3,681,920
Schedule of condensed consolidating statement of income	Following is the consolidating statement of operations for the three months ended March 31, 2017 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 443,305 $ 131,071 $ (14,162 ) $ 560,214 Product revenues — 116,650 15,331 (3,254 ) 128,727 Total revenues — 559,955 146,402 (17,416 ) 688,941 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 294,145 111,104 (14,162 ) 391,087 Product cost of revenues — 96,505 12,247 (3,254 ) 105,498 Total cost of revenues — 390,650 123,351 (17,416 ) 496,585 Selling, general and administrative expenses 24 92,171 20,026 — 112,221 Accretion of environmental liabilities — 2,055 235 — 2,290 Depreciation and amortization — 51,900 20,512 — 72,412 (Loss) income from operations (24 ) 23,179 (17,722 ) — 5,433 Other expense (146 ) (1,389 ) (14 ) — (1,549 ) Interest (expense) income (22,659 ) 119 (36 ) — (22,576 ) Equity in earnings of subsidiaries, net of taxes (7,637 ) (21,824 ) — 29,461 — Intercompany interest income (expense) — 1,297 (1,297 ) — — (Loss) income before (benefit) provision for income taxes (30,466 ) 1,382 (19,069 ) 29,461 (18,692 ) (Benefit) provision for income taxes (9,073 ) 9,637 2,137 — 2,701 Net loss (21,393 ) (8,255 ) (21,206 ) 29,461 (21,393 ) Other comprehensive income 6,051 6,051 5,032 (11,083 ) 6,051 Comprehensive loss $ (15,342 ) $ (2,204 ) $ (16,174 ) $ 18,378 $ (15,342 ) Following is the consolidating statement of operations for the three months ended March 31, 2016 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Revenues Service revenues $ — $ 428,477 $ 114,023 $ (12,269 ) $ 530,231 Product revenues — 89,588 18,713 (2,449 ) 105,852 Total revenues — 518,065 132,736 (14,718 ) 636,083 Cost of revenues (exclusive of items shown separately below) Service cost of revenues — 282,964 103,291 (12,269 ) 373,986 Product cost of revenues — 79,354 13,388 (2,449 ) 90,293 Total cost of revenues — 362,318 116,679 (14,718 ) 464,279 Selling, general and administrative expenses 24 80,655 23,805 — 104,484 Accretion of environmental liabilities — 2,290 215 — 2,505 Depreciation and amortization — 48,695 20,207 — 68,902 (Loss) income from operations (24 ) 24,107 (28,170 ) — (4,087 ) Other expense — (88 ) (262 ) — (350 ) Interest (expense) income (20,143 ) 1,111 52 — (18,980 ) Equity in earnings of subsidiaries, net of taxes (8,771 ) (26,495 ) — 35,266 — Intercompany interest income (expense) — 5,159 (5,159 ) — — (Loss) income before (benefit) provision for income taxes (28,938 ) 3,794 (33,539 ) 35,266 (23,417 ) (Benefit) provision for income taxes (8,067 ) 12,565 (7,044 ) — (2,546 ) Net loss (20,871 ) (8,771 ) (26,495 ) 35,266 (20,871 ) Other comprehensive income 45,837 45,837 28,927 (74,764 ) 45,837 Comprehensive income $ 24,966 $ 37,066 $ 2,432 $ (39,498 ) $ 24,966
Schedule of condensed consolidating statement of cash flows	Following is the condensed consolidating statement of cash flows for the three months ended March 31, 2017 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash (used in) from operating activities $ (1,663 ) $ 41,144 $ 17,638 $ — $ 57,119 Cash flows from (used in) investing activities: Additions to property, plant and equipment — (33,136 ) (9,326 ) — (42,462 ) Proceeds from sales of fixed assets — 664 366 — 1,030 Acquisitions, net of cash acquired — (11,946 ) — — (11,946 ) Proceeds on sale of business 1,837 — 181 — 2,018 Costs to obtain or renew permits — (573 ) (178 ) — (751 ) Proceeds from sale of investments 243 — — — 243 Intercompany — (7,771 ) — 7,771 — Net cash from (used in) investing activities 2,080 (52,762 ) (8,957 ) 7,771 (51,868 ) Cash flows used in financing activities: Change in uncashed checks — (5,165 ) (2,392 ) — (7,557 ) Proceeds from exercise of stock options 46 — — — 46 Issuance of restricted shares, net of shares remitted (1,021 ) — — — (1,021 ) Repurchases of common stock (6,796 ) — — — (6,796 ) Deferred financing costs paid (108 ) — — — (108 ) Intercompany 7,771 — — (7,771 ) — Net cash used in financing activities (108 ) (5,165 ) (2,392 ) (7,771 ) (15,436 ) Effect of exchange rate change on cash — — 554 — 554 Increase (decrease) in cash and cash equivalents 309 (16,783 ) 6,843 — (9,631 ) Cash and cash equivalents, beginning of period 51,417 155,943 99,637 — 306,997 Cash and cash equivalents, end of period $ 51,726 $ 139,160 $ 106,480 $ — $ 297,366 Following is the condensed consolidating statement of cash flows for the three months ended March 31, 2016 (in thousands): Clean Harbors, Inc. Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating Adjustments Total Net cash from (used in) operating activities $ 47,201 $ (3,361 ) $ (4,551 ) $ — $ 39,289 Cash flows used in investing activities: Additions to property, plant and equipment — (64,754 ) (11,027 ) — (75,781 ) Proceeds from sales of fixed assets — 277 996 — 1,273 Acquisitions, net of cash acquired — (34,993 ) — — (34,993 ) Costs to obtain or renew permits — (465 ) (47 ) — (512 ) Intercompany — (6,423 ) — 6,423 — Investment in subsidiaries (250,625 ) — — 250,625 — Net cash used in investing activities (250,625 ) (106,358 ) (10,078 ) 257,048 (110,013 ) Cash flows from (used in) financing activities: Change in uncashed checks — (4,529 ) (689 ) — (5,218 ) Issuance of restricted shares, net of shares remitted (1,425 ) — — — (1,425 ) Repurchases of common stock (4,998 ) — — — (4,998 ) Deferred financing costs paid (2,190 ) — — — (2,190 ) Issuance of senior secured notes, including premium 250,625 250,625 — (250,625 ) 250,625 Intercompany 6,423 — — (6,423 ) — Net cash from (used in) financing activities 248,435 246,096 (689 ) (257,048 ) 236,794 Effect of exchange rate change on cash — — 4,567 — 4,567 Increase (decrease) in cash and cash equivalents 45,011 136,377 (10,751 ) — 170,637 Cash and cash equivalents, beginning of period 11,017 83,479 90,212 — 184,708 Cash and cash equivalents, end of period $ 56,028 $ 219,856 $ 79,461 $ — $ 355,345

SIGNIFICANT ACCOUNTING POLICI44

SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017segment	Dec. 31, 2016USD ($)
Accounting Policies [Abstract]
Number of operating segments | segment	6
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting for Stock based compensation		$ 231
Accumulated Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting for Stock based compensation		(450)
Accumulated Earnings | Accounting Standards Updated 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting for Stock based compensation		$ (500)

BUSINESS COMBINATIONS (Narrativ

BUSINESS COMBINATIONS (Narrative) (Details) $ in Thousands	Jan. 31, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)aquisitionrerefinery
Business Acquisition [Line Items]
Goodwill recognized		$ 4,938
2017 Acquisitions
Business Acquisition [Line Items]
Purchase price	$ 11,900
Goodwill recognized	$ 4,900
2016 Acquisitions
Business Acquisition [Line Items]
Purchase price			$ 205,000
Number of acquisitions | aquisition			7
Number of re-refineries acquired | rerefinery			3

BUSINESS COMBINATIONS (Assets A

BUSINESS COMBINATIONS (Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 469,860	$ 465,154
2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	16,396
Measurement period adjustments, accounts receivable	629
Inventories and supplies	12,688
Measurement period adjustment, inventories and supplies	173
Prepaid and other current assets	752
Measurement period adjustment, prepaid and other current assets	(25)
Property, plant and equipment	143,650
Measurement period adjustments, property, plant and equipment	625
Permits and other intangibles	28,856
Measurement period adjustments, permits and other intangibles	0
Current liabilities	(19,866)
Measurement period adjustments, current liabilities	392
Closure and post-closure liabilities	(3,004)
Measurement period adjustments, closure and post-closure liabilities	(596)
Remedial liabilities, less current portion	(2,025)
Measurement period adjustments, remedial liabilities, less current portion	16
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(17,475)
Measurement period adjustments, deferred taxes, unrecognized tax benefits and other long-term liabilities	(456)
Total identifiable net assets	159,972
Measurement period adjustments, total identifiable net assets	758
Goodwill	45,060
Measurement period adjustments, goodwill	(731)
Total purchase price, net of cash acquired	205,032
Measurement period adjustments, total purchase price, net of cash acquired	$ 27
At Acquisition Dates As Reported December 31, 2016 | 2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable		15,767
Inventories and supplies		12,515
Prepaid and other current assets		777
Property, plant and equipment		143,025
Permits and other intangibles		28,856
Current liabilities		(20,258)
Closure and post-closure liabilities		(2,408)
Remedial liabilities, less current portion		(2,041)
Deferred taxes, unrecognized tax benefits and other long-term liabilities		(17,019)
Total identifiable net assets		159,214
Goodwill		45,791
Total purchase price, net of cash acquired		$ 205,005

DISPOSITION OF BUSINESS (Income

DISPOSITION OF BUSINESS (Income (Loss) Attributable to Catalyst Services) (Details) - Catalyst Services - Disposal Group, Disposed of by Sale, Not Discontinued Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Final sale proceeds		$ 2,000
Loss before benefit for income taxes	$ 1,099

INVENTORIES AND SUPPLIES (Detai

INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Oil and oil products	$ 55,872	$ 52,158
Supplies and drums	91,210	90,610
Solvent and solutions	8,865	8,566
Modular camp accommodations	14,859	15,255
Other	11,232	11,839
Total inventories and supplies	$ 182,038	$ 178,428

PROPERTY, PLANT AND EQUIPMENT49

PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 3,033,496		$ 2,977,904
Less - accumulated depreciation and amortization	1,424,006		1,366,077
Total property, plant and equipment, net	1,609,490		1,611,827
Interest costs capitalized adjustment	100	$ 1,200
Depreciation inclusive of amortization	63,300	$ 59,300
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	122,184		120,575
Asset retirement costs (non-landfill)
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	15,173		14,567
Landfill assets
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	140,518		139,708
Buildings and improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	406,562		373,160
Camp equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	151,561		152,740
Vehicles
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	558,175		541,022
Equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	1,591,511		1,483,736
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	5,507		5,492
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 42,305		$ 146,904

GOODWILL AND OTHER INTANGIBLE50

GOODWILL AND OTHER INTANGIBLE ASSETS (Rollforward of Goodwill) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Goodwill [Roll Forward]
Balance at beginning of year	$ 465,154
Increase from current period acquisitions	4,938
Measurement period adjustments from prior period acquisitions	(731)
Foreign currency translation and other	499
Balance at end of year	469,860
Technical Services
Goodwill [Roll Forward]
Balance at beginning of year	61,116
Balance at end of year	61,158
Industrial and Field Services
Goodwill [Roll Forward]
Balance at beginning of year	107,968
Balance at end of year	108,131
Safety-Kleen
Goodwill [Roll Forward]
Balance at beginning of year	296,070
Balance at end of year	300,571
Oil, Gas and Lodging Services
Goodwill [Roll Forward]
Balance at beginning of year	0
Balance at end of year	0
Operating Segments | Technical Services
Goodwill [Roll Forward]
Balance at beginning of year	61,116
Increase from current period acquisitions	0
Measurement period adjustments from prior period acquisitions	0
Foreign currency translation and other	42
Balance at end of year	61,158
Operating Segments | Industrial and Field Services
Goodwill [Roll Forward]
Balance at beginning of year	107,968
Increase from current period acquisitions	0
Measurement period adjustments from prior period acquisitions	0
Foreign currency translation and other	163
Balance at end of year	108,131
Operating Segments | Safety-Kleen
Goodwill [Roll Forward]
Balance at beginning of year	296,070
Increase from current period acquisitions	4,938
Measurement period adjustments from prior period acquisitions	(731)
Foreign currency translation and other	294
Balance at end of year	300,571
Operating Segments | Oil, Gas and Lodging Services
Goodwill [Roll Forward]
Balance at beginning of year	0
Increase from current period acquisitions	0
Measurement period adjustments from prior period acquisitions	0
Foreign currency translation and other	0
Balance at end of year	$ 0

GOODWILL AND OTHER INTANGIBLE51

GOODWILL AND OTHER INTANGIBLE ASSETS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of permits and other intangible assets	$ 9.1	$ 9.6

GOODWILL AND OTHER INTANGIBLE52

GOODWILL AND OTHER INTANGIBLE ASSETS (Amortizable Other Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	$ 601,215	$ 599,317
Accumulated Amortization	232,978	223,219
Net	$ 368,237	$ 376,098
Weighted Average Remaining Amortization Period (in years)	14 years 329 days	13 years 9 months 40 days
Total permits and other intangible assets, Cost	$ 723,930	$ 721,940
Total permits and other intangible assets, Net	490,952	498,721
Trademarks and trade names
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Trademarks and trade names	122,715	122,623
Permits
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	172,666	171,637
Accumulated Amortization	69,151	67,301
Net	$ 103,515	$ 104,336
Weighted Average Remaining Amortization Period (in years)	19 years 277 days	18 years 9 months 40 days
Customer and supplier relationships
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	$ 394,086	$ 393,426
Accumulated Amortization	134,599	127,462
Net	$ 259,487	$ 265,964
Weighted Average Remaining Amortization Period (in years)	11 years 318 days	12 years 2 months
Other intangible assets
Schedule of Finite-lived and Indefinite-lived Intangible Assets [Line Items]
Cost	$ 34,463	$ 34,254
Accumulated Amortization	29,228	28,456
Net	$ 5,235	$ 5,798
Weighted Average Remaining Amortization Period (in years)	7 years 36 days	7 years 1 month

GOODWILL AND OTHER INTANGIBLE53

GOODWILL AND OTHER INTANGIBLE ASSETS (Expected Future Amortization) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
2017 (nine months)	$ 27,392
2,018	34,072
2,019	31,275
2,020	29,067
2,021	26,640
Thereafter	219,791
Net	$ 368,237	$ 376,098

ACCRUED EXPENSES (Details)

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Insurance	$ 56,603	$ 63,061
Interest	21,770	21,536
Accrued compensation and benefits	41,109	34,641
Income, real estate, sales and other taxes	29,814	35,083
Other	34,661	36,400
Total accrued expenses	183,957	190,721
Accrued legal matters	4,200	3,800
Accrued severance charges	$ 2,300	$ 2,900

CLOSURE AND POST-CLOSURE LIAB55

CLOSURE AND POST-CLOSURE LIABILITIES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Changes to post-closure liabilities
Beginning balance	$ 58,331
Measurement period adjustments from prior period acquisitions	596
New asset retirement obligations	431
Accretion	1,157
Changes in estimates recorded to statement of operations	(6)
Expenditures	(192)
Currency translation and other	34
Ending balance	$ 60,351
Credit-adjusted risk-free rate	6.12%
Landfill Retirement Liability
Changes to post-closure liabilities
Beginning balance	$ 30,630
Measurement period adjustments from prior period acquisitions	0
New asset retirement obligations	431
Accretion	534
Changes in estimates recorded to statement of operations	0
Expenditures	(119)
Currency translation and other	20
Ending balance	31,496
Non-Landfill Retirement Liability
Changes to post-closure liabilities
Beginning balance	27,701
Measurement period adjustments from prior period acquisitions	596
New asset retirement obligations	0
Accretion	623
Changes in estimates recorded to statement of operations	(6)
Expenditures	(73)
Currency translation and other	14
Ending balance	$ 28,855

REMEDIAL LIABILITIES (Details)

REMEDIAL LIABILITIES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	$ 128,007
Measurement period adjustments from prior period acquisitions	(16)
Accretion	1,133
Changes in estimates recorded to statement of operations	108
Expenditures	(2,746)
Currency translation and other	121
Balance at end of year	126,607
Remedial Liabilities for Landfill Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	1,777
Measurement period adjustments from prior period acquisitions	0
Accretion	21
Changes in estimates recorded to statement of operations	(38)
Expenditures	(7)
Currency translation and other	0
Balance at end of year	1,753
Remedial Liabilities for Inactive Sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	64,151
Measurement period adjustments from prior period acquisitions	0
Accretion	615
Changes in estimates recorded to statement of operations	(94)
Expenditures	(720)
Currency translation and other	8
Balance at end of year	63,960
Remedial Liabilities (Including Superfund) for Non-Landfill Operations
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at beginning of year	62,079
Measurement period adjustments from prior period acquisitions	(16)
Accretion	497
Changes in estimates recorded to statement of operations	240
Expenditures	(2,019)
Currency translation and other	113
Balance at end of year	$ 60,894

FINANCING ARRANGEMENTS (Details

FINANCING ARRANGEMENTS (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Financing arrangements
Long-term obligations, at par	$ 1,645,000,000	$ 1,645,000,000
Unamortized debt issuance costs and premium, net	(11,032,000)	(11,728,000)
Long-term obligations, at carrying value	1,633,968,000	1,633,272,000
Revolving credit facility, amount outstanding	0	0
Revolving credit facility, available borrowing capacity	194,000,000	195,200,000
Letters of credit amount outstanding	126,000,000	132,600,000
Unsecured debt | Senior unsecured notes, at 5.25%, due August 1, 2020 (2020 Notes)
Financing arrangements
Long-term obligations, at par	$ 800,000,000	800,000,000
Stated interest rate	5.25%
Fair value	$ 814,000,000	820,000,000
Unsecured debt | Senior unsecured notes, at 5.125%, due June 1, 2021 (2021 Notes)
Financing arrangements
Long-term obligations, at par	$ 845,000,000	845,000,000
Stated interest rate	5.125%
Fair value	$ 861,900,000	$ 861,900,000

LOSS PER SHARE (Computation of

LOSS PER SHARE (Computation of Basic and Diluted Earnings Per Share)(Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator for basic and diluted loss per share:
Net loss	$ (21,393)	$ (20,871)
Denominator:
Basic shares outstanding (in shares)	57,262	57,617
Dilutive effect of equity-based compensation awards (in shares)	0	0
Dilutive shares outstanding (in shares)	57,262	57,617
Basic loss per share (in USD per share)	$ (0.37)	$ (0.36)
Diluted loss per share (in USD per share)	$ (0.37)	$ (0.36)

LOSS PER SHARE (Narrative) (Det

LOSS PER SHARE (Narrative) (Details) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Shares excluded from computation of earning per share (in shares)	659,558	474,318

ACCUMULATED OTHER COMPREHENSI60

ACCUMULATED OTHER COMPREHENSIVE LOSS (Changes in Accumulated Other Comprehensive Loss by Component) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,084,241,000
Other comprehensive income before reclassifications	6,057,000
Amounts reclassified out of accumulated other comprehensive loss	146,000	$ 0
Tax effects	(152,000)
Other comprehensive income	6,051,000
Balance at end of period	1,063,630,000
Foreign Currency Translation
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(212,211,000)
Other comprehensive income before reclassifications	5,823,000
Amounts reclassified out of accumulated other comprehensive loss	0
Tax effects	0
Other comprehensive income	5,823,000
Balance at end of period	(206,388,000)
Unrealized Gains on Available-For-Sale Securities
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(321,000)
Other comprehensive income before reclassifications	234,000
Amounts reclassified out of accumulated other comprehensive loss	146,000
Tax effects	(152,000)
Other comprehensive income	228,000
Balance at end of period	(93,000)
Unfunded Pension Liability
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(1,794,000)
Other comprehensive income before reclassifications	0
Amounts reclassified out of accumulated other comprehensive loss	0
Tax effects	0
Other comprehensive income	0
Balance at end of period	(1,794,000)
Total
Components of Other Accumulated Income, Net of Tax [Roll Forward]
Balance at beginning of period	(214,326,000)
Balance at end of period	$ (208,275,000)

ACCUMULATED OTHER COMPREHENSI61

ACCUMULATED OTHER COMPREHENSIVE LOSS (Amount Reclassified Out of Accumulated Other Comprehensive Loss) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Equity [Abstract]
Amounts reclassified out of accumulated other comprehensive loss	$ (146,000)	$ 0

STOCK-BASED COMPENSATION (Narra

STOCK-BASED COMPENSATION (Narrative) (Details) - USD ($) shares in Millions	3 Months Ended		25 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 13, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,300,000	$ 2,100,000
Income tax benefit	$ 800,000	500,000
Share repurchase program authorized				$ 300,000,000
Repurchases of common stock (in shares)	0.1		4
Repurchases of common stock	$ 6,796,000		$ 206,700,000
Stock repurchase program, remaining authorized repurchase amount	93,300,000		93,300,000
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 18,500,000		18,500,000
Period for recognition	3 years
Fair value restricted stock	$ 1,500,000	3,800,000
Performance stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	1,000,000		$ 1,000,000
Fair value restricted stock	$ 1,400,000	$ 400,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years

STOCK-BASED COMPENSATION (Restr

STOCK-BASED COMPENSATION (Restricted Stock) (Details) - Restricted stock awards	3 Months Ended
	Mar. 31, 2017$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	510,041
Granted (in shares) | shares	22,794
Vested (in shares) | shares	(26,963)
Forfeited (in shares) | shares	(29,218)
Ending balance (in shares) | shares	476,654
Weighted Average Grant-Date Fair Value
Beginning of period (in USD per share) | $ / shares	$ 52.65
Granted (in USD per share) | $ / shares	55.64
Vested (in USD per share) | $ / shares	54.45
Forfeited (in USD per share) | $ / shares	50.97
End of period (in USD per share) | $ / shares	$ 52.80

STOCK-BASED COMPENSATION (Perfo

STOCK-BASED COMPENSATION (Performance Stock Awards (Details) - Performance stock awards	3 Months Ended
	Mar. 31, 2017$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	220,882
Granted (in shares) | shares	588
Vested (in shares) | shares	(25,168)
Forfeited (in shares) | shares	(13,398)
Ending balance (in shares) | shares	182,904
Weighted Average Grant-Date Fair Value
Beginning of period (in USD per share) | $ / shares	$ 54.69
Granted (in USD per share) | $ / shares	54.44
Vested (in USD per share) | $ / shares	54.84
Forfeited (in USD per share) | $ / shares	56.26
End of period (in USD per share) | $ / shares	$ 54.69

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) CAD in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2017USD ($)siteproceedingclaim	Dec. 31, 2012CAD	Dec. 31, 1999municipality	Dec. 31, 1968permit	Dec. 31, 2016USD ($)proceeding
Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $	$ 21,900,000				$ 22,000,000
Number of pending personal injury claims allegedly resulting from the use of Safety-Kleen's products | proceeding	58
Number of product liability claims settled or dismissed | claim	9
Legal and Administrative Proceedings
Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $	$ 17,700,000				18,200,000
Possible increase in legal and administrative proceedings | $	$ 1,700,000				1,900,000
Ville Mercier
Contingencies [Line Items]
Number of permits issued by government, for dumping organic liquid | permit				2
Number of neighboring municipalities filing separate legal proceedings against the Mercier Subsidiary and the Government of Quebec | municipality			3
General damages sought | CAD		CAD 2.9
Punitive damages sought | CAD		CAD 10
Superfund Proceedings
Contingencies [Line Items]
Number of sites owned by third party excluded from cleanup or related liabilities	129
Number of sites owned by the entity subject to proceedings under federal or state superfund laws	3
Notices received from owners of third party sites seeking indemnification from the company	126
Number of sites for which environmental remediation expense is settled	33
Third party sites requiring expenditure on remediation	16
Number of sites not currently requiring expenditures on remediation	77
Number of sites which potential liability could exceed $100,000	11
Notices received from owners of third party sites seeking indemnification from the company	17
Superfund Proceedings | Minimum
Contingencies [Line Items]
Minimum potential liability | $	$ 100,000
ChemWaste
Contingencies [Line Items]
Indemnification agreement with third party sites	11
Safety-Kleen
Contingencies [Line Items]
Notices received from owners of third party sites seeking indemnification from the company	6
Federal and State Enforcement Actions
Contingencies [Line Items]
Recorded reserves for actual or probable liabilities | $	$ 4,200,000				$ 3,800,000
Number of pending personal injury claims allegedly resulting from the use of Safety-Kleen's products | proceeding	4				5
Federal and State Enforcement Actions | Minimum
Contingencies [Line Items]
Minimum potential liability | $	$ 100,000				$ 100,000

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	(14.50%)	10.90%
Unrecognized tax benefits	$ 1.7		$ 1.7
Interest on unrecognized tax benefits	0.3		$ 0.3
Reduction in unrecognized tax benefits from expiring statue of limitations	$ 0.5

SEGMENT REPORTING (Narrative) (

SEGMENT REPORTING (Narrative) (Details)	3 Months Ended
	Mar. 31, 2017segment
Segment Reporting [Abstract]
Number of operating segments	6

SEGMENT REPORTING (Third Party

SEGMENT REPORTING (Third Party Revenues to Direct Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 688,941	$ 636,083
Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	0	0
Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	0	0
Direct revenues
Segment Reporting Information [Line Items]
Total revenues	688,941	636,083
Technical Services
Segment Reporting Information [Line Items]
Total revenues	230,218	219,105
Technical Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	40,044	34,844
Technical Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	722	388
Technical Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	270,984	254,337
Industrial and Field Services
Segment Reporting Information [Line Items]
Total revenues	133,557	130,187
Industrial and Field Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(8,359)	(6,675)
Industrial and Field Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	104	(13)
Industrial and Field Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	125,302	123,499
Safety-Kleen
Segment Reporting Information [Line Items]
Total revenues	292,901	246,961
Safety-Kleen | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(32,069)	(28,521)
Safety-Kleen | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	3	366
Safety-Kleen | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	260,835	218,806
Oil, Gas and Lodging Services
Segment Reporting Information [Line Items]
Total revenues	32,132	39,051
Oil, Gas and Lodging Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	384	352
Oil, Gas and Lodging Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	94	104
Oil, Gas and Lodging Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	32,610	39,507
Corporate Items
Segment Reporting Information [Line Items]
Total revenues	133	779
Corporate Items | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	0	0
Corporate Items | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	(923)	(845)
Corporate Items | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	$ (790)	$ (66)

SEGMENT REPORTING (Adjusted EBI

SEGMENT REPORTING (Adjusted EBITDA Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 80,135	$ 67,320
Reconciliation to Consolidated Statements of Operations:
Accretion of environmental liabilities	2,290	2,505
Depreciation and amortization	72,412	68,902
Income (loss) from operations	5,433	(4,087)
Other expense	1,549	350
Interest expense, net of interest income	22,576	18,980
(Loss) income before (benefit) provision for income taxes	(18,692)	(23,417)
Technical Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	58,488	60,398
Industrial and Field Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	1,913	433
Safety-Kleen
Segment Reporting Information [Line Items]
Adjusted EBITDA	52,368	40,055
Oil, Gas and Lodging Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	(211)	1,310
Corporate Items
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ (32,423)	$ (34,876)

SEGMENT REPORTING (Assets by Re

SEGMENT REPORTING (Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 1,609,490	$ 1,611,827
Goodwill	469,860	465,154
Permits and other intangibles, net	490,952	498,721
Total assets	3,645,653	3,681,920
Technical Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	521,726	521,134
Goodwill	61,158	61,116
Permits and other intangibles, net	77,131	78,625
Total assets	856,324	862,957
Industrial and Field Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	245,250	245,143
Goodwill	108,131	107,968
Permits and other intangibles, net	17,973	17,817
Total assets	446,757	446,826
Safety-Kleen
Segment Reporting Information [Line Items]
Property, plant and equipment, net	589,782	584,647
Goodwill	300,571	296,070
Permits and other intangibles, net	386,125	391,390
Total assets	1,477,851	1,474,755
Oil, Gas and Lodging Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	173,347	182,038
Goodwill	0	0
Permits and other intangibles, net	9,723	10,889
Total assets	246,910	253,242
Corporate Items
Segment Reporting Information [Line Items]
Property, plant and equipment, net	79,385	78,865
Goodwill	0	0
Permits and other intangibles, net	0	0
Total assets	$ 617,811	$ 644,140

SEGMENT REPORTING (Total Assets

SEGMENT REPORTING (Total Assets by Geographical Area) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 3,645,653	$ 3,681,920
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	2,947,064	2,960,337
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 698,589	$ 721,583

GUARANTOR AND NON-GUARANTOR S72

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Narrative) (Details)	3 Months Ended
	Mar. 31, 2017
Guarantor and Non-Guarantor Subsidiaries Financial Information [Abstract]
Ownership percentage of U.S. guarantor subsidiaries	100.00%

GUARANTOR AND NON-GUARANTOR S73

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 297,366	$ 306,997	$ 355,345	$ 184,708
Intercompany receivables	0	0
Accounts receivable, net	480,044	496,226
Other current assets	284,361	289,648
Property, plant and equipment, net	1,609,490	1,611,827
Investments in subsidiaries	0	0
Intercompany debt receivable	0	0
Goodwill	469,860	465,154
Permits and other intangibles, net	490,952	498,721
Other long-term assets	13,580	13,347
Total assets	3,645,653	3,681,920
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	488,581	504,668
Intercompany payables	0	0
Closure, post-closure and remedial liabilities, net	165,389	166,322
Long-term obligations	1,633,968	1,633,272
Intercompany debt payable	0	0
Other long-term liabilities	294,085	293,417
Total liabilities	2,582,023	2,597,679
Stockholders’ equity	1,063,630	1,084,241
Total liabilities and stockholders’ equity	3,645,653	3,681,920
Reportable Legal Entities | Clean Harbors, Inc.
ASSETS
Cash and cash equivalents	51,726	51,417	56,028	11,017
Intercompany receivables	209,410	200,337
Accounts receivable, net	0	0
Other current assets	1,033	3,096
Property, plant and equipment, net	0	0
Investments in subsidiaries	2,849,584	2,851,571
Intercompany debt receivable	0	0
Goodwill	0	0
Permits and other intangibles, net	0	0
Other long-term assets	2,421	2,446
Total assets	3,114,174	3,108,867
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	22,063	21,805
Intercompany payables	390,812	365,848
Closure, post-closure and remedial liabilities, net	0	0
Long-term obligations	1,633,968	1,633,272
Intercompany debt payable	3,701	3,701
Other long-term liabilities	0	0
Total liabilities	2,050,544	2,024,626
Stockholders’ equity	1,063,630	1,084,241
Total liabilities and stockholders’ equity	3,114,174	3,108,867
Reportable Legal Entities | Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	139,160	155,943	219,856	83,479
Intercompany receivables	396,286	354,836
Accounts receivable, net	400,764	417,029
Other current assets	235,715	234,408
Property, plant and equipment, net	1,214,176	1,211,210
Investments in subsidiaries	563,331	580,124
Intercompany debt receivable	87,215	86,409
Goodwill	417,224	412,638
Permits and other intangibles, net	429,311	435,594
Other long-term assets	7,661	7,582
Total assets	3,890,843	3,895,773
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	356,914	366,831
Intercompany payables	245,871	237,058
Closure, post-closure and remedial liabilities, net	148,992	150,682
Long-term obligations	0	0
Intercompany debt payable	21,000	21,000
Other long-term liabilities	276,118	275,649
Total liabilities	1,048,895	1,051,220
Stockholders’ equity	2,841,948	2,844,553
Total liabilities and stockholders’ equity	3,890,843	3,895,773
Reportable Legal Entities | Non-Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	106,480	99,637	79,461	90,212
Intercompany receivables	40,235	49,055
Accounts receivable, net	79,280	79,197
Other current assets	59,592	69,257
Property, plant and equipment, net	395,314	400,617
Investments in subsidiaries	0	0
Intercompany debt receivable	24,701	24,701
Goodwill	52,636	52,516
Permits and other intangibles, net	61,641	63,127
Other long-term assets	4,566	4,387
Total assets	824,445	842,494
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	121,583	133,145
Intercompany payables	9,248	1,322
Closure, post-closure and remedial liabilities, net	16,397	15,640
Long-term obligations	0	0
Intercompany debt payable	87,215	86,409
Other long-term liabilities	19,035	18,836
Total liabilities	253,478	255,352
Stockholders’ equity	570,967	587,142
Total liabilities and stockholders’ equity	824,445	842,494
Consolidating Adjustments
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Intercompany receivables	(645,931)	(604,228)
Accounts receivable, net	0	0
Other current assets	(11,979)	(17,113)
Property, plant and equipment, net	0	0
Investments in subsidiaries	(3,412,915)	(3,431,695)
Intercompany debt receivable	(111,916)	(111,110)
Goodwill	0	0
Permits and other intangibles, net	0	0
Other long-term assets	(1,068)	(1,068)
Total assets	(4,183,809)	(4,165,214)
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities	(11,979)	(17,113)
Intercompany payables	(645,931)	(604,228)
Closure, post-closure and remedial liabilities, net	0	0
Long-term obligations	0	0
Intercompany debt payable	(111,916)	(111,110)
Other long-term liabilities	(1,068)	(1,068)
Total liabilities	(770,894)	(733,519)
Stockholders’ equity	(3,412,915)	(3,431,695)
Total liabilities and stockholders’ equity	$ (4,183,809)	$ (4,165,214)

GUARANTOR AND NON-GUARANTOR S74

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Consolidating Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues:
Service revenues	$ 560,214	$ 530,231
Product revenues	128,727	105,852
Total revenues	688,941	636,083
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	391,087	373,986
Product cost of revenues	105,498	90,293
Total cost of revenues	496,585	464,279
Selling, general and administrative expenses	112,221	104,484
Accretion of environmental liabilities	2,290	2,505
Depreciation and amortization	72,412	68,902
(Loss) income from operations	5,433	(4,087)
Other expense	(1,549)	(350)
Interest (expense) income	(22,576)	(18,980)
Equity in earnings of subsidiaries, net of taxes	0	0
Intercompany interest income (expense)	0	0
(Loss) income before (benefit) provision for income taxes	(18,692)	(23,417)
(Benefit) provision for income taxes	2,701	(2,546)
Net loss	(21,393)	(20,871)
Other comprehensive income	6,051	45,837
Comprehensive (loss) income	(15,342)	24,966
Reportable Legal Entities | Clean Harbors, Inc.
Revenues:
Service revenues	0	0
Product revenues	0	0
Total revenues	0	0
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	0	0
Product cost of revenues	0	0
Total cost of revenues	0	0
Selling, general and administrative expenses	24	24
Accretion of environmental liabilities	0	0
Depreciation and amortization	0	0
(Loss) income from operations	(24)	(24)
Other expense	(146)	0
Interest (expense) income	(22,659)	(20,143)
Equity in earnings of subsidiaries, net of taxes	(7,637)	(8,771)
Intercompany interest income (expense)	0	0
(Loss) income before (benefit) provision for income taxes	(30,466)	(28,938)
(Benefit) provision for income taxes	(9,073)	(8,067)
Net loss	(21,393)	(20,871)
Other comprehensive income	6,051	45,837
Comprehensive (loss) income	(15,342)	24,966
Reportable Legal Entities | Guarantor Subsidiaries
Revenues:
Service revenues	443,305	428,477
Product revenues	116,650	89,588
Total revenues	559,955	518,065
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	294,145	282,964
Product cost of revenues	96,505	79,354
Total cost of revenues	390,650	362,318
Selling, general and administrative expenses	92,171	80,655
Accretion of environmental liabilities	2,055	2,290
Depreciation and amortization	51,900	48,695
(Loss) income from operations	23,179	24,107
Other expense	(1,389)	(88)
Interest (expense) income	119	1,111
Equity in earnings of subsidiaries, net of taxes	(21,824)	(26,495)
Intercompany interest income (expense)	1,297	5,159
(Loss) income before (benefit) provision for income taxes	1,382	3,794
(Benefit) provision for income taxes	9,637	12,565
Net loss	(8,255)	(8,771)
Other comprehensive income	6,051	45,837
Comprehensive (loss) income	(2,204)	37,066
Reportable Legal Entities | Non-Guarantor Subsidiaries
Revenues:
Service revenues	131,071	114,023
Product revenues	15,331	18,713
Total revenues	146,402	132,736
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	111,104	103,291
Product cost of revenues	12,247	13,388
Total cost of revenues	123,351	116,679
Selling, general and administrative expenses	20,026	23,805
Accretion of environmental liabilities	235	215
Depreciation and amortization	20,512	20,207
(Loss) income from operations	(17,722)	(28,170)
Other expense	(14)	(262)
Interest (expense) income	(36)	52
Equity in earnings of subsidiaries, net of taxes	0	0
Intercompany interest income (expense)	(1,297)	(5,159)
(Loss) income before (benefit) provision for income taxes	(19,069)	(33,539)
(Benefit) provision for income taxes	2,137	(7,044)
Net loss	(21,206)	(26,495)
Other comprehensive income	5,032	28,927
Comprehensive (loss) income	(16,174)	2,432
Consolidating Adjustments
Revenues:
Service revenues	(14,162)	(12,269)
Product revenues	(3,254)	(2,449)
Total revenues	(17,416)	(14,718)
Cost of revenues (exclusive of items shown separately below)
Service cost of revenues	(14,162)	(12,269)
Product cost of revenues	(3,254)	(2,449)
Total cost of revenues	(17,416)	(14,718)
Selling, general and administrative expenses	0	0
Accretion of environmental liabilities	0	0
Depreciation and amortization	0	0
(Loss) income from operations	0	0
Other expense	0	0
Interest (expense) income	0	0
Equity in earnings of subsidiaries, net of taxes	29,461	35,266
Intercompany interest income (expense)	0	0
(Loss) income before (benefit) provision for income taxes	29,461	35,266
(Benefit) provision for income taxes	0	0
Net loss	29,461	35,266
Other comprehensive income	(11,083)	(74,764)
Comprehensive (loss) income	$ 18,378	$ (39,498)

GUARANTOR AND NON-GUARANTOR S75

GUARANTOR AND NON-GUARANTOR SUBSIDIARIES FINANCIAL INFORMATION (Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed consolidating statement of cash flows
Net cash (used in) from operating activities	$ 57,119	$ 39,289
Cash flows from (used in) investing activities:
Additions to property, plant and equipment	(42,462)	(75,781)
Proceeds from sales of fixed assets	1,030	1,273
Acquisitions, net of cash acquired	(11,946)	(34,993)
Proceeds on sale of business	2,018	0
Costs to obtain or renew permits	(751)	(512)
Proceeds from sale of investments	243	0
Intercompany	0	0
Investment in subsidiaries		0
Net cash used in investing activities	(51,868)	(110,013)
Cash flows used in financing activities:
Change in uncashed checks	(7,557)	(5,218)
Proceeds from exercise of stock options	46	0
Issuance of restricted shares, net of shares remitted	(1,021)	(1,425)
Repurchases of common stock	(6,796)	(4,998)
Deferred financing costs paid	(108)	(2,190)
Issuance of senior secured notes, including premium	0	250,625
Intercompany	0	0
Net cash (used in) from financing activities	(15,436)	236,794
Effect of exchange rate change on cash	554	4,567
Increase (decrease) in cash and cash equivalents	(9,631)	170,637
Cash and cash equivalents, beginning of period	306,997	184,708
Cash and cash equivalents, end of period	297,366	355,345
Consolidating Adjustments
Condensed consolidating statement of cash flows
Net cash (used in) from operating activities	0	0
Cash flows from (used in) investing activities:
Additions to property, plant and equipment	0	0
Proceeds from sales of fixed assets	0	0
Acquisitions, net of cash acquired	0	0
Proceeds on sale of business	0
Costs to obtain or renew permits	0	0
Proceeds from sale of investments	0
Intercompany	7,771	6,423
Investment in subsidiaries		250,625
Net cash used in investing activities	7,771	257,048
Cash flows used in financing activities:
Change in uncashed checks	0	0
Proceeds from exercise of stock options	0
Issuance of restricted shares, net of shares remitted	0	0
Repurchases of common stock	0	0
Deferred financing costs paid	0	0
Issuance of senior secured notes, including premium		(250,625)
Intercompany	(7,771)	(6,423)
Net cash (used in) from financing activities	(7,771)	(257,048)
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Clean Harbors, Inc. | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash (used in) from operating activities	(1,663)	47,201
Cash flows from (used in) investing activities:
Additions to property, plant and equipment	0	0
Proceeds from sales of fixed assets	0	0
Acquisitions, net of cash acquired	0	0
Proceeds on sale of business	1,837
Costs to obtain or renew permits	0	0
Proceeds from sale of investments	243
Intercompany	0	0
Investment in subsidiaries		(250,625)
Net cash used in investing activities	2,080	(250,625)
Cash flows used in financing activities:
Change in uncashed checks	0	0
Proceeds from exercise of stock options	46
Issuance of restricted shares, net of shares remitted	(1,021)	(1,425)
Repurchases of common stock	(6,796)	(4,998)
Deferred financing costs paid	(108)	(2,190)
Issuance of senior secured notes, including premium		250,625
Intercompany	7,771	6,423
Net cash (used in) from financing activities	(108)	248,435
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	309	45,011
Cash and cash equivalents, beginning of period	51,417	11,017
Cash and cash equivalents, end of period	51,726	56,028
Guarantor Subsidiaries | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash (used in) from operating activities	41,144	(3,361)
Cash flows from (used in) investing activities:
Additions to property, plant and equipment	(33,136)	(64,754)
Proceeds from sales of fixed assets	664	277
Acquisitions, net of cash acquired	(11,946)	(34,993)
Proceeds on sale of business	0
Costs to obtain or renew permits	(573)	(465)
Proceeds from sale of investments	0
Intercompany	(7,771)	(6,423)
Investment in subsidiaries		0
Net cash used in investing activities	(52,762)	(106,358)
Cash flows used in financing activities:
Change in uncashed checks	(5,165)	(4,529)
Proceeds from exercise of stock options	0
Issuance of restricted shares, net of shares remitted	0	0
Repurchases of common stock	0	0
Deferred financing costs paid	0	0
Issuance of senior secured notes, including premium		250,625
Intercompany	0	0
Net cash (used in) from financing activities	(5,165)	246,096
Effect of exchange rate change on cash	0	0
Increase (decrease) in cash and cash equivalents	(16,783)	136,377
Cash and cash equivalents, beginning of period	155,943	83,479
Cash and cash equivalents, end of period	139,160	219,856
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed consolidating statement of cash flows
Net cash (used in) from operating activities	17,638	(4,551)
Cash flows from (used in) investing activities:
Additions to property, plant and equipment	(9,326)	(11,027)
Proceeds from sales of fixed assets	366	996
Acquisitions, net of cash acquired	0	0
Proceeds on sale of business	181
Costs to obtain or renew permits	(178)	(47)
Proceeds from sale of investments	0
Intercompany	0	0
Investment in subsidiaries		0
Net cash used in investing activities	(8,957)	(10,078)
Cash flows used in financing activities:
Change in uncashed checks	(2,392)	(689)
Proceeds from exercise of stock options	0
Issuance of restricted shares, net of shares remitted	0	0
Repurchases of common stock	0	0
Deferred financing costs paid	0	0
Issuance of senior secured notes, including premium		0
Intercompany	0	0
Net cash (used in) from financing activities	(2,392)	(689)
Effect of exchange rate change on cash	554	4,567
Increase (decrease) in cash and cash equivalents	6,843	(10,751)
Cash and cash equivalents, beginning of period	99,637	90,212
Cash and cash equivalents, end of period	$ 106,480	$ 79,461