Arq (ARQ) 10-Q 12 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 06, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	Advanced Emissions Solutions, Inc.
Entity Central Index Key	0001515156
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		18,588,896

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash, cash equivalents and restricted cash	$ 15,155	$ 18,577
Receivables, net	6,771	9,554
Receivables, related parties	4,382	4,284
Inventories, net	16,917	21,791
Prepaid expenses and other assets	6,070	5,570
Total current assets	49,295	59,776
Restricted cash, long-term	5,000	5,195
Property, plant and equipment, net of accumulated depreciation of $5,651 and $1,499, respectively	44,168	42,697
Intangible assets, net	4,300	4,830
Equity method investments	44,111	6,634
Deferred tax assets, net	13,491	32,539
Other long-term assets, net	18,363	7,993
Total Assets	178,728	159,664
Current liabilities:
Accounts payable	6,838	6,235
Accrued payroll and related liabilities	3,893	8,279
Current portion of long-term debt	24,072	24,067
Other current liabilities	4,287	2,138
Total current liabilities	39,090	40,719
Long-term debt	26,276	50,058
Other long-term liabilities	6,062	940
Total Liabilities	71,428	91,717
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock: par value of $.001 per share, 50,000,000 shares authorized, none outstanding	0	0
Common stock: par value of $.001 per share, 100,000,000 shares authorized, 22,915,429 and 22,640,677 shares issued, and 18,594,498 and 18,576,489 shares outstanding at September 30, 2019 and December 31, 2018, respectively	23	23
Treasury stock, at cost: 4,320,931 and 4,064,188 shares as of September 30, 2019 and December 31, 2018, respectively	(44,666)	(41,740)
Additional paid-in capital	97,706	96,750
Retained earnings	54,237	12,914
Total stockholders’ equity	107,300	67,947
Total Liabilities and Stockholders’ Equity	$ 178,728	$ 159,664

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Accumulated depreciation and amortization	$ 5,651	$ 1,499
Preferred stock par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	22,915,429	22,640,677
Common stock, shares outstanding (in shares)	18,594,498	18,576,489
Treasury stock (in shares)	4,320,931	4,064,188

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Total revenues	$ 19,133	$ 5,147	$ 54,039	$ 13,319
Operating expenses:
Payroll and benefits	2,651	2,555	8,005	7,528
Legal and professional fees	1,755	698	5,300	3,459
General and administrative	3,136	834	7,699	3,098
Depreciation, amortization, depletion and accretion	2,043	74	4,902	262
Total operating expenses	21,524	5,115	64,245	16,568
Operating (loss) income	(2,391)	32	(10,206)	(3,249)
Other income (expense):
Earnings from equity method investments	14,426	9,715	57,051	37,857
Interest expense	(1,729)	(399)	(5,820)	(1,147)
Other	212	86	342	146
Total other income	12,909	9,402	51,573	36,856
Income before income tax expense	10,518	9,434	41,367	33,607
Income tax expense	6,595	3,931	14,928	5,151
Net income	$ 3,923	$ 5,503	$ 26,439	$ 28,456
Earnings per common share (Note 1):
Basic (in dollars per share)	$ 0.22	$ 0.28	$ 1.45	$ 1.41
Diluted (in dollars per share)	$ 0.21	$ 0.28	$ 1.44	$ 1.40
Weighted-average number of common shares outstanding:
Basic (in shares)	18,112	19,726	18,184	20,090
Diluted (in shares)	18,339	19,876	18,394	20,228
Consumables
Revenues:
Total revenues	$ 14,748	$ 1,043	$ 41,243	$ 2,390
Operating expenses:
Cost of revenue	11,939	954	38,339	2,567
License royalties, related party
Revenues:
Total revenues	4,385	4,104	12,796	10,857
Other
Revenues:
Total revenues	0	0	0	72
Operating expenses:
Cost of revenue	$ 0	$ 0	$ 0	$ (346)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings (Deficit)
Beginning Balance (in shares) at Dec. 31, 2017		22,465,821	(1,713,766)
Beginning Balance at Dec. 31, 2017	$ 73,455	$ 22	$ (16,397)	$ 105,308	$ (15,478)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		193,583
Stock-based compensation	336	$ 1		335
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(22,375)
Repurchase of common shares to satisfy minimum tax withholdings	(267)			(267)
Cash dividends declared on common stock, $0.25 per share	(5,189)			(5,189)
Repurchase of common shares (in shares)			(149,217)
Repurchase of common shares	(1,642)		$ (1,642)
Net income	7,662				7,662
Ending Balance (in shares) at Mar. 31, 2018		22,637,029	(1,862,983)
Ending Balance at Mar. 31, 2018	77,305	$ 23	$ (18,039)	100,187	(4,866)
Beginning Balance (in shares) at Dec. 31, 2017		22,465,821	(1,713,766)
Beginning Balance at Dec. 31, 2017	73,455	$ 22	$ (16,397)	105,308	(15,478)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common shares to satisfy minimum tax withholdings		$ (11,200)
Net income	28,456
Ending Balance (in shares) at Sep. 30, 2018		22,646,524	(2,725,396)
Ending Balance at Sep. 30, 2018	79,604	$ 23	$ (27,566)	96,251	10,896
Beginning Balance (in shares) at Mar. 31, 2018		22,637,029	(1,862,983)
Beginning Balance at Mar. 31, 2018	77,305	$ 23	$ (18,039)	100,187	(4,866)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		(1,135)
Stock-based compensation	675			675
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(8,259)
Repurchase of common shares to satisfy minimum tax withholdings	(92)			(92)
Cash dividends declared on common stock, $0.25 per share	(5,090)			(5,090)
Repurchase of common shares (in shares)			(676,201)
Repurchase of common shares	(7,469)		$ (7,469)
Net income	15,291				15,291
Ending Balance (in shares) at Jun. 30, 2018		22,627,635	(2,539,184)
Ending Balance at Jun. 30, 2018	80,620	$ 23	$ (25,508)	95,680	10,425
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		24,726
Stock-based compensation	919			919
Stock issued from exercise of stock options (in shares)		18,667
Stock issued from exercise of stock options	0
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(24,504)
Repurchase of common shares to satisfy minimum tax withholdings	(348)	$ (2,100)		(348)
Cash dividends declared on common stock, $0.25 per share	(5,032)				(5,032)
Repurchase of common shares (in shares)			(186,212)
Repurchase of common shares	(2,058)		$ (2,058)
Net income	5,503				5,503
Ending Balance (in shares) at Sep. 30, 2018		22,646,524	(2,725,396)
Ending Balance at Sep. 30, 2018	79,604	$ 23	$ (27,566)	96,251	10,896
Beginning Balance (in shares) at Dec. 31, 2018		22,640,677	(4,064,188)
Beginning Balance at Dec. 31, 2018	67,947	$ 23	$ (41,740)	96,750	12,914
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		218,465
Stock-based compensation	317			317
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(22,707)
Repurchase of common shares to satisfy minimum tax withholdings	(245)			(245)
Cash dividends declared on common stock, $0.25 per share	(4,629)				(4,629)
Repurchase of common shares (in shares)			(63,876)
Repurchase of common shares	(693)		$ (693)
Net income	14,402				14,402
Ending Balance (in shares) at Mar. 31, 2019		22,836,435	(4,128,064)
Ending Balance at Mar. 31, 2019	105,916	$ 23	$ (42,433)	96,822	51,504
Beginning Balance (in shares) at Dec. 31, 2018		22,640,677	(4,064,188)
Beginning Balance at Dec. 31, 2018	67,947	$ 23	$ (41,740)	96,750	12,914
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common shares to satisfy minimum tax withholdings		$ (2,900)
Net income	26,439
Ending Balance (in shares) at Sep. 30, 2019		22,915,429	(4,320,931)
Ending Balance at Sep. 30, 2019	107,300	$ 23	$ (44,666)	97,706	54,237
Beginning Balance (in shares) at Mar. 31, 2019		22,836,435	(4,128,064)
Beginning Balance at Mar. 31, 2019	105,916	$ 23	$ (42,433)	96,822	51,504
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		31,715
Stock-based compensation	541			541
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(745)
Repurchase of common shares to satisfy minimum tax withholdings	(9)			(9)
Cash dividends declared on common stock, $0.25 per share	(4,663)				(4,663)
Repurchase of common shares (in shares)			(184,715)
Repurchase of common shares	(2,138)		$ (2,138)
Net income	8,114				8,114
Ending Balance (in shares) at Jun. 30, 2019		22,867,405	(4,312,779)
Ending Balance at Jun. 30, 2019	107,761	$ 23	$ (44,571)	97,354	54,955
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)		22,305
Stock-based compensation	468			468
Stock issued from exercise of stock options (in shares)		25,820
Stock issued from exercise of stock options	0
Repurchase of common shares to satisfy minimum tax withholdings (in shares)		(101)
Repurchase of common shares to satisfy minimum tax withholdings	(116)	$ (100)		(116)
Cash dividends declared on common stock, $0.25 per share	(4,641)				(4,641)
Repurchase of common shares (in shares)			(8,152)
Repurchase of common shares	(95)		$ (95)
Net income	3,923				3,923
Ending Balance (in shares) at Sep. 30, 2019		22,915,429	(4,320,931)
Ending Balance at Sep. 30, 2019	$ 107,300	$ 23	$ (44,666)	$ 97,706	$ 54,237

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per common share outstanding (in dollars per share)	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.75	$ 0.75

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities
Net income	$ 26,439	$ 28,456
Adjustments to reconcile net income to net cash provided by operating activities:
Increase in valuation allowance on deferred tax assets	3,822	2,731
Depreciation, amortization, depletion and accretion	4,902	262
Operating lease expense	2,371	0
Amortization of debt discount and debt issuance costs	1,324	0
Stock-based compensation expense	1,326	1,929
Earnings from equity method investments	(57,051)	(37,857)
Other non-cash items, net	697	190
Changes in operating assets and liabilities:
Receivables and related party receivables	2,685	(375)
Prepaid expenses and other assets	(440)	(797)
Costs incurred on uncompleted contracts	0	15,945
Inventories	4,566	0
Deferred tax assets, net	6,812	(966)
Other long-term assets	(43)	0
Accounts payable	1,010	(340)
Accrued payroll and related liabilities	(4,386)	587
Other current liabilities	(278)	(1,974)
Billings on uncompleted contracts	0	(15,945)
Operating lease liabilities	(2,435)	0
Other long-term liabilities	(529)	(157)
Distributions from equity method investees, return on investment	56,806	4,000
Net cash provided by (used in) operating activities	47,598	(4,311)
Cash flows from investing activities
Distributions from equity method investees in excess of cumulative earnings	0	33,575
Acquisition of business	(661)	0
Acquisition of property, plant, equipment, and intangible assets, net	(6,430)	(191)
Mine development costs	(2,083)	0
Contributions to equity method investees	0	750
Net cash (used in) provided by investing activities	(9,174)	32,634
Cash flows from financing activities
Principal payments on term loan	(24,000)	0
Principal payments on finance lease obligations	(1,016)	0
Dividends paid	(13,729)	(15,226)
Repurchase of common shares	(2,926)	(11,169)
Repurchase of common shares to satisfy tax withholdings	(370)	(707)
Net cash used in financing activities	(42,041)	(27,102)
(Decrease) increase in Cash and Cash Equivalents and Restricted Cash	(3,617)	1,221
Cash and Cash Equivalents and Restricted Cash, beginning of period	23,772	30,693
Cash and Cash Equivalents and Restricted Cash, end of period	20,155	31,914
Supplemental disclosure of non-cash investing and financing activities:
Dividends declared, not paid	$ 204	$ 85

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Nature of Operations Advanced Emissions Solutions, Inc. ("ADES" or the "Company") is a Delaware corporation with its principal office located in Highlands Ranch, Colorado and operations located in Louisiana. The Company is principally engaged in consumable mercury control options including powdered activated carbon ("PAC") and chemical technologies. The Company's proprietary environmental technologies in the power generation and industrial ("PGI") market enable customers to reduce emissions of mercury and other pollutants, maximize utilization levels and improve operating efficiencies to meet the challenges of existing and pending emission control regulations. The Company generates substantial earnings and tax credits under Section 45 ("Section 45 tax credits") of the Internal Revenue Code ("IRC") from its equity investments in certain entities and earns royalties for technologies that are licensed to Tinuum Group, LLC, a Colorado limited liability company ("Tinuum Group"). Such technologies allow Tinuum Group to provide their customers with various solutions to enhance combustion and reduced emissions of nitrogen oxide ("NOx") and mercury from coal burned to generate electrical power. The Company’s sales occur principally throughout the United States. See Note 13 for additional information regarding the Company's operating segments. On December 7, 2018 (the "Acquisition Date"), the Company acquired (the "Carbon Solutions Acquisition") 100% of the equity interests of ADA Carbon Solutions, LLC (“Carbon Solutions”). Carbon Solutions is a manufacturer and seller of activated carbon ("AC") used in mercury capture for the coal-fired power plant, industrial and water treatment markets. Carbon Solutions also owns an associated lignite mine that supplies the primary raw material for manufacturing PAC. Carbon Solutions was formed in 2008 as a 50/50 joint venture by the Company and Energy Capital Partners LLC. The Company relinquished its ownership in 2011 as part of a legal settlement agreement as described in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2017. The Company acquired Carbon Solutions primarily to expand the Company's product offerings within the mercury control industry and other complementary PAC markets. Basis of Presentation The accompanying Condensed Consolidated Financial Statements of ADES are unaudited and have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP") and with Article 10 of Regulation S-X of the Securities and Exchange Commission. In compliance with those instructions, certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The unaudited Condensed Consolidated Financial Statements of ADES in this quarterly report ("Quarterly Report") are presented on a consolidated basis and include ADES and its wholly-owned subsidiaries (collectively, the "Company"). Also included within the unaudited Condensed Consolidated Financial Statements are the Company's unconsolidated equity investments; Tinuum Group, Tinuum Services, LLC ("Tinuum Services"), and GWN Manager, LLC ("GWN Manager"), which are accounted for under the equity method of accounting, and Highview Enterprises Limited (the "Highview Investment"), which is accounted for in accordance with U.S. GAAP applicable to equity investments that do not qualify for the equity method of accounting. Results of operations and cash flows for the interim periods are not necessarily indicative of the results that may be expected for the entire year. All significant intercompany transactions and accounts were eliminated for all periods presented in this Quarterly Report. In the opinion of management, these Condensed Consolidated Financial Statements include all normal and recurring adjustments considered necessary for a fair presentation of the results of operations, financial position, stockholders' equity and cash flows for the interim periods presented. These Condensed Consolidated Financial Statements of ADES should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 (the "2018 Form 10-K"). Significant accounting policies disclosed therein have not changed, except as described later in Note 1. Earnings Per Share Basic earnings per share is computed using the two-class method, which is an earnings allocation formula that determines earnings per share for common stock and any participating securities according to dividend and participating rights in undistributed earnings. The Company's restricted stock awards ("RSA's") granted prior to December 31, 2016 contain non-forfeitable rights to dividends or dividend equivalents and are deemed to be participating securities. RSA's granted subsequent to December 31, 2016 do not contain non-forfeitable rights to dividends and are not deemed to be participating securities. Under the two-class method, net income for the period is allocated between common stockholders and the holders of the participating securities based on the weighted-average number of common shares outstanding during the period, excluding participating, unvested RSA's ("common shares"), and the weighted-average number of participating unvested RSA's outstanding during the period, respectively. The allocated, undistributed income for the period is then divided by the weighted-average number of common shares and participating, unvested RSA's outstanding during the period to arrive at basic earnings per common share and participating security for the period, respectively. Pursuant to U.S. GAAP, the Company has elected not to separately present basic or diluted earnings per share attributable to participating securities in the Condensed Consolidated Statements of Operations. Diluted earnings per share is computed in a manner consistent with that of basic earnings per share, while considering other potentially dilutive securities. Potentially dilutive securities consist of both unvested, participating and non-participating RSA's, as well as outstanding options to purchase common stock ("Stock Options") and contingent performance stock units ("PSU's") (collectively, "Potential dilutive shares"). The dilutive effect, if any, for non-participating RSA's, Stock Options and PSU's is determined using the greater of dilution as calculated under the treasury stock method or the two-class method. Potential dilutive shares are excluded from diluted earnings per share when their effect is anti-dilutive. When there is a net loss for a period, all Potential dilutive shares are anti-dilutive and are excluded from the calculation of diluted loss per share for that period. The following table sets forth the calculations of basic and diluted earnings per share: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except per share amounts) 2019 2018 2019 2018 Net income $ 3,923 $ 5,503 $ 26,439 $ 28,456 Less: Dividends and undistributed income allocated to participating securities 5 18 37 94 Income attributable to common stockholders $ 3,918 $ 5,485 $ 26,402 $ 28,362 Basic weighted-average common shares outstanding 18,112 19,726 18,184 20,090 Add: dilutive effect of equity instruments 227 150 210 138 Diluted weighted-average shares outstanding 18,339 19,876 18,394 20,228 Earnings per share - basic $ 0.22 $ 0.28 $ 1.45 $ 1.41 Earnings per share - diluted $ 0.21 $ 0.28 $ 1.44 $ 1.40 For the three and nine months ended September 30, 2019 and 2018 , RSA's and Stock Options convertible to 0.3 million and 0.3 million shares, respectively, and 0.3 million and 0.3 million shares, respectively, of common stock for each of the periods presented were outstanding but were not included in the computation of diluted net income per share because the effect would have been anti-dilutive. For the nine months ended September 30, 2018 , Stock Options to purchase 0.1 million shares, which vest based on the Company achieving specified performance targets, were outstanding, but were not included in the computation of diluted net income per share for a portion of this period because they were determined not to be contingently issuable. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. There have been no changes in the Company’s critical accounting estimates from those that were disclosed in the 2018 Form 10-K. Actual results could differ from these estimates. Risks and Uncertainties The Company’s earnings are significantly affected by equity earnings it receives from Tinuum Group. As of September 30, 2019 , Tinuum Group has 23 invested RC facilities of which 11 are leased to a single customer. A majority of these leases are periodically renewed and the loss of this single customer or material modification to the lease terms of these facilities by this customer would have a significant adverse impact on Tinuum Group's financial position, results of operations and cash flows, which in turn would have material adverse impact on the Company’s financial position, results of operations and cash flows. The Company's revenues, sales volumes, earnings and cash flows are significantly affected by prices of competing power generation sources such as natural gas and renewable energy. Low natural gas prices make it a competitive alternative to coal-fired power generation and therefore, coal consumption may be reduced, which reduces the demand for our products. In addition, coal consumption and demand for our products is also affected by the demand for electricity, which is higher in the warmer and colder months of the year. Abnormal temperatures during the summer and winter months may significantly reduce coal consumption and thus the demand for the Company's products. Reclassifications Certain balances have been reclassified from the prior year to conform to the current year presentation. No reclassifications have any impact to income before income taxes or net income. New Accounting Standards Recently Adopted In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) ("ASU 2016-02"), which created ASC Topic 842 - Leases ("ASC 842"), requiring lessees to recognize a right of use asset and related lease liability for those leases classified as operating leases at the commencement date and have lease terms of more than 12 months. ASC 842 retains the distinction between finance leases (formerly defined as capital leases) and operating leases. On January 1, 2019, the Company adopted ASC 842 retrospectively beginning with the date of adoption. Under this adoption method, the application date is the beginning of the reporting period in which the Company first applies the provisions of ASC 842. Accordingly, the Company’s reporting for the comparative periods presented in the financial statements and related disclosures continues in accordance with legacy U.S. GAAP under ASC Topic 840 - Leases ("ASC 840"). The adoption of ASC 842 had no impact to the opening balance of Retained earnings. As of the adoption date, the Company recorded $7.0 million and $7.0 million of "right of use" ("ROU") assets and incremental lease liabilities, respectively. The cumulative effect of the change from the adoption of ASC 842 to the Consolidated Balance Sheet as of January 1, 2019 is shown in the table that follows: Balance as of Impact of Balance as of (in thousands) December 31, 2018 Adoption January 1, 2019 Balance Sheet Other long-term assets $ 7,993 $ 6,956 $ 14,949 Other liabilities $ 50,058 $ 3,085 $ 53,143 Other long-term liabilities $ 940 $ 3,871 $ 4,811 See Note 6 for additional disclosures required under ASC 842 in the year of adoption. As of January 1, 2019, Tinuum Group adopted ASU 2016-02 and ASU 2014-09 (Topic 606), Revenue from Contracts with Customers and related pronouncements ("ASC 606"). As a result of Tinuum Group’s adoption of these pronouncements, the Company recorded a cumulative effect increase of $28.8 million to Retained earnings as of January 1, 2019, based on the Company's ownership percentage of Tinuum Group's cumulative effect adjustment, and increased its investment balance in Tinuum Group in the amount of $37.2 million and established a deferred tax liability of $8.4 million . As a result of the increase in the investment balance in Tinuum Group, for the nine months ended September 30, 2019 , the Company recognized equity earnings in Tinuum Group based on its pro-rata share of Tinuum Group’s net income rather than based on cash distributions received as had been required in prior periods as a result of the cumulative cash distributions exceeding the cumulative pro-rata share of Tinuum Group's net income. Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). The main objective of ASU 2016-13 is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. To achieve this objective, the amendments in ASU 2016-13 replace the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those years, and must be adopted under a modified retrospective method approach. Entities may adopt ASU 2016-13 earlier as of the fiscal years beginning after December 15, 2018, including interim periods within those years. The Company is currently evaluating the provisions of this guidance and assessing its impact on the Company's financial statements and disclosures. The Company does not believe this standard will have a material impact on the Company's financial statements and disclosures. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement ("ASU 2018-13"). The amendments in ASU 2018-13 improve the effectiveness of fair value measurement disclosures and modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement ("Topic 820"), based on the concepts in FASB Concepts Statement, Conceptual Framework for Financial Reporting - Chapter 8: Notes to Financial Statements, including the consideration of costs and benefits. ASU 2018-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted-average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted upon issuance of this update. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this update and delay adoption of the additional disclosures until their effective date. The Company is currently evaluating the provisions of ASU 2018-13 and assessing its impact on the Company's financial statement disclosures. The Company does not believe this standard will have a material impact on the Company's financial statement disclosures.

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Acquisition	Acquisition As described in Note 1 , on the Acquisition Date, the Company completed the Carbon Solutions Acquisition for a total purchase price of $75.0 million (the "Purchase Price"). The results of Carbon Solutions have been included in the Company’s consolidated financial statements since the Acquisition Date. The fair value of the purchase consideration totaled $66.5 million and consisted of cash of $65.8 million and an additional purchase adjustment amount payable to Carbon Solutions' secured lender of $0.7 million , which was paid in March 2019. The Purchase Price was adjusted by assumed debt and contractual commitments of $11.8 million , less cash acquired of $3.3 million . The Company also paid $4.5 million in acquisition-related costs (or transaction costs) during the year ended December 31, 2018. The Company funded the cash consideration from cash on hand and the proceeds from the Term Loan and Security Agreement (the "Senior Term Loan") in the principal amount of $70.0 million , as more fully described in Note 5 . The following table summarizes the final purchase price allocation. Subsequent to December 31, 2018 , the Company completed additional analysis and adjustments were made to the preliminary purchase price allocations as noted in the table below: Fair value of assets acquired: As Originally Reported Adjustments As Adjusted Cash $ 3,284 $ — $ 3,284 Receivables 6,409 — 6,409 Inventories 22,100 (356 ) 21,744 Prepaid expenses and other current assets 2,992 61 3,053 Spare parts 3,359 — 3,359 Property, plant and equipment 43,033 (377 ) 42,656 Mine leases and development 2,500 200 2,700 Mine reclamation asset — 2,402 2,402 Intangible assets 4,000 100 4,100 Other assets 168 — 168 Amount attributable to assets acquired 87,845 2,030 89,875 Fair value of liabilities assumed: Accounts payable 4,771 — 4,771 Accrued liabilities 7,354 254 7,608 Equipment lease liabilities 8,211 — 8,211 Mine reclamation liability 626 1,776 2,402 Other liabilities 437 — 437 Amount attributable to liabilities assumed 21,399 2,030 23,429 Net assets acquired $ 66,446 $ — $ 66,446 Adjustments to the preliminary purchase price allocation primarily relate to changes in fair values assigned to property, plant and equipment, intangible assets, mine reclamation liability and the related mine reclamation asset as a result of the final valuation report from the Company's third-party valuation firm issued in May 2019. During the three months ended June 30, 2019 based on new information of facts and circumstances that existed as of the Acquisition Date, the Company revised its estimates used as of the Acquisition Date related to the net realizable value of certain finished goods inventory items as well as values assigned to certain prepaid and accrued expense items. The adjustments were recorded as of June 30, 2019 and were included in the Consolidated Balance Sheet as of that date and the resultant impact to the Statement of Operations was reflected for the three months ended June 30, 2019. The following table represents the intangible assets, as adjusted for purchase price adjustments noted above, identified as part of the Carbon Solutions Acquisition: (in thousands) Amount Weighted Average Useful Life (years) Customer relationships $ 2,200 5 Developed technology 1,600 5 Trade name 300 2 Total intangibles acquired $ 4,100 Unaudited Pro Forma Financial Information The following represents the pro forma effects of the Carbon Solutions Acquisition as if it had occurred on January 1, 2017. The pro forma pre-tax income for the period presented has been calculated after applying the Company’s accounting policies in effect for 2017 and 2018. In addition, pro forma net income for the three and nine months ended September 30, 2018 includes: (1) the impact on Carbon Solutions of the adoption of ASC 606 effective January 1, 2018, which resulted in a reclassification of $2.1 million and $5.9 million , respectively, from Revenues to Cost of Revenue for freight costs billed to customers, with no impact to income from operations; (2) the reduction in depletion, depreciation and amortization resulting from the purchase price adjustments to Property, plant and equipment and Mine development costs; (3) the adjustment to interest expense from the combination of the Senior Term Loan that was used to fund the Carbon Solutions Acquisition and the elimination of certain debt of Carbon Solutions as a result of pay-offs by the Company as of the Acquisition Date; and (4) the removal of $1.0 million and $4.2 million in transaction costs incurred for the three and nine months ended September 30, 2018 , respectively, together with the income tax effect on (1) through (4). The pro forma results do not include any anticipated synergies or other expected benefits of the Carbon Solutions Acquisition. The unaudited pro forma financial information below is not necessarily indicative of either future results of operations or results that might have been achieved had the Carbon Solutions Acquisition been consummated as of January 1, 2017. The following table presents the pro forma effects of the Carbon Solutions Acquisition for the three and nine months ended September 30, 2018 : Three Months Ended Nine Months Ended (in thousands) September 30, 2018 September 30, 2018 Revenues $ 22,447 $ 57,597 Net income $ 8,372 $ 24,434

Inventories

Inventories	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories The following table summarizes the Company's inventories recorded at the lower of average cost or net realizable value as of September 30, 2019 and December 31, 2018 : As of (in thousands) September 30, 2019 December 31, 2018 Product inventory (1) $ 14,953 $ 19,403 Raw material inventory 1,964 2,388 $ 16,917 $ 21,791 (1) As of September 30, 2019 and December 31, 2018, Product inventory includes zero and $5.0 million , respectively, attributed to the increase in fair value of inventory acquired from the Carbon Solutions Acquisition.

Equity Method Investments

Equity Method Investments	9 Months Ended
	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Equity Method Investments Tinuum Group, LLC The Company's ownership interest in Tinuum Group was 42.5% as of September 30, 2019 and December 31, 2018 . Tinuum Group supplies technology equipment and technical services at select coal-fired generators, but its primary purpose is to put into operation facilities that produce and sell refined coal ("RC") that lower emissions and also qualify for Section 45 tax credits. Tinuum Group has been determined to be a variable interest entity ("VIE"); however, the Company does not have the power to direct the activities that most significantly impact Tinuum Group's economic performance and has therefore accounted for the investment under the equity method of accounting. The Company determined that the voting partners of Tinuum Group have identical voting rights, equity control interests and board control interests, and therefore, concluded that the power to direct the activities that most significantly impact Tinuum Group's economic performance was shared. The following table summarizes the results of operations of Tinuum Group: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Gross profit $ 16,810 $ 26,530 $ 96,189 $ 81,626 Operating, selling, general and administrative expenses 11,076 5,908 23,421 17,406 Income from operations 5,734 20,622 72,768 64,220 Other expenses (450 ) (577 ) (427 ) (2,801 ) Class B preferred return — — — (12 ) Loss attributable to noncontrolling interest 22,355 17,126 51,022 38,145 Net income available to members $ 27,639 $ 37,171 $ 123,363 $ 99,552 ADES equity earnings from Tinuum Group $ 11,746 $ 8,075 $ 50,757 $ 33,575 For the three and nine months ended September 30, 2018 periods presented in the table below, the difference between the Company's proportionate share of Tinuum Group's net income available to members (at its equity interest of 42.5% ) and the Company's earnings from its Tinuum Group equity method investment as reported in the Condensed Consolidated Statements of Operations relates to the Company receiving distributions in excess of the carrying value of the equity investment, and therefore recognizing such excess distributions as equity method earnings in the period the distributions occur, as discussed below. For the three and nine months ended September 30, 2018 periods presented in the table below, the Company recognized equity earnings from Tinuum Group to the extent that cash distributions were received from Tinuum Group during the period. For the three months ended September 30, 2019 , the Company recognized its pro-rata share of Tinuum Group's net income available to its members for the respective period. For the nine months ended September 30, 2019 , the Company recognized its pro-rata share of Tinuum Group's net income available to its members for the period, less the amount necessary to recover the cumulative earnings short-fall balance as of the end of the immediately preceding period, which was December 31, 2018 . For the three and nine months ended September 30, 2019 , the Company recognized equity earnings from Tinuum Group of $11.7 million and $50.8 million , respectively. For the three and nine months ended September 30, 2018 , the Company recognized equity earnings from Tinuum Group of $8.1 million and $33.6 million , respectively. As of September 30, 2019 and December 31, 2018 , the Company's carrying value in Tinuum Group was $37.7 million and zero , respectively. The following tables present the Company's investment balance, equity earnings and cash distributions in excess of the investment balance, if any, for the three and nine months ended September 30, 2019 and 2018 ( in thousands ): Description Date(s) Investment balance ADES equity earnings (loss) Cash distributions Memorandum Account: Cash distributions and equity earnings in (excess) of investment balance Beginning balance 12/31/2018 $ — $ — $ — $ (1,672 ) Impact of adoption of accounting standards (1) First Quarter 37,232 — — — ADES proportionate share of income from Tinuum Group First Quarter 21,439 21,439 — — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) First Quarter (1,672 ) (1,672 ) — 1,672 Cash distributions from Tinuum Group First Quarter (16,788 ) — 16,788 — Total investment balance, equity earnings (loss) and cash distributions 03/31/2019 $ 40,211 $ 19,767 $ 16,788 $ — ADES proportionate share of income from Tinuum Group Second Quarter $ 19,244 $ 19,244 $ — $ — Cash distributions from Tinuum Group Second Quarter (17,000 ) — 17,000 — Total investment balance, equity earnings (loss) and cash distributions 6/30/2019 $ 42,455 $ 19,244 $ 17,000 $ — ADES proportionate share of income from Tinuum Group Third Quarter $ 11,746 $ 11,746 $ — $ — Cash distributions from Tinuum Group Third Quarter (16,468 ) — 16,468 — Total investment balance, equity earnings (loss) and cash distributions 9/30/2019 $ 37,733 $ 11,746 $ 16,468 $ — Description Date(s) Investment balance ADES equity earnings (loss) Cash distributions Memorandum Account: Cash distributions and equity earnings in (excess) of investment balance Beginning balance 12/31/2017 $ — $ — $ — $ (12,218 ) ADES proportionate share of income from Tinuum Group (2) First Quarter 12,458 12,458 — — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) First Quarter (12,218 ) (12,218 ) — 12,218 Cash distributions from Tinuum Group First Quarter (11,050 ) — 11,050 — Adjustment for current year cash distributions in excess of investment balance First Quarter 10,810 10,810 — (10,810 ) Total investment balance, equity earnings (loss) and cash distributions 3/31/2018 $ — $ 11,050 $ 11,050 $ (10,810 ) ADES proportionate share of income from Tinuum Group (2) Second Quarter $ 14,059 $ 14,059 $ — $ — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) Second Quarter (10,810 ) (10,810 ) — 10,810 Cash distributions from Tinuum Group Second Quarter (14,450 ) — 14,450 — Adjustment for current year cash distributions in excess of investment balance Second Quarter 11,201 11,201 — (11,201 ) Total investment balance, equity earnings (loss) and cash distributions 6/30/2018 $ — $ 14,450 $ 14,450 $ (11,201 ) ADES proportionate share of income from Tinuum Group (2) Third Quarter $ 15,798 $ 15,798 $ — $ — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) Third Quarter (11,201 ) (11,201 ) — 11,201 Cash distributions from Tinuum Group Third Quarter (8,075 ) — 8,075 — Adjustment for current year cash distributions in excess of investment balance Third Quarter 3,478 3,478 — (3,478 ) Total investment balance, equity earnings (loss) and cash distributions 9/30/2018 $ — $ 8,075 $ 8,075 $ (3,478 ) (1) As discussed in Note 1 , Tinuum Group adopted ASC 606 and ASC 842 as of January 1, 2019. As a result of Tinuum Group’s adoption of these standards, the Company recorded a cumulative adjustment of $28.8 million , net of the impact of income taxes, related to the Company's percentage of Tinuum Group's cumulative effect adjustment that increased the Company's Retained earnings as of January 1, 2019. (2) For the three and nine months ended September 30, 2018 , the amount of the Company's 42.5% proportionate share of net income available to members as shown in the table above may differ from mathematical calculations of the Company’s 42.5% equity interest in Tinuum Group multiplied by the amounts of net income available to members as shown in the table above of Tinuum Group's results of operations due to adjustments related to the Class B preferred return. Tinuum Services, LLC The Company has a 50% voting and economic interest in Tinuum Services, which is equivalent to the voting and economic interest of NexGen Refined Coal, LLC ("NexGen"). The Company has determined that Tinuum Services is not a VIE and has evaluated its consolidation analysis under the voting interest model. Because the Company does not own greater than 50% of the outstanding voting shares, either directly or indirectly, it has accounted for its investment in Tinuum Services under the equity method of accounting. The Company’s investment in Tinuum Services as of September 30, 2019 and December 31, 2018 was $6.3 million and $6.6 million , respectively. The following table summarizes the results of operations of Tinuum Services: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Gross loss $ (27,834 ) $ (21,362 ) $ (77,761 ) $ (64,069 ) Operating, selling, general and administrative expenses 51,927 43,947 151,789 127,783 Loss from operations (79,761 ) (65,309 ) (229,550 ) (191,852 ) Other (expenses) income (460 ) 78 (1,018 ) 443 Loss attributable to noncontrolling interest 85,586 68,509 243,163 199,971 Net income $ 5,365 $ 3,278 $ 12,595 $ 8,562 ADES equity earnings from Tinuum Services $ 2,682 $ 1,639 $ 6,297 $ 4,281 Included within the Consolidated Statements of Operations of Tinuum Services for the three and nine months ended September 30, 2019 and 2018 , respectively, were losses related to VIE's of Tinuum Services. These losses do not impact the Company's equity earnings from Tinuum Services as 100% of those losses are attributable to a noncontrolling interest and eliminated in the calculations of Tinuum Services' net income attributable to the Company's interest. The following table details the components of the Company's respective equity method investments included within the Earnings from equity method investments line item on the Condensed Consolidated Statements of Operations : Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Earnings from Tinuum Group $ 11,746 $ 8,075 $ 50,757 $ 33,575 Earnings from Tinuum Services 2,682 1,639 6,297 4,281 (Losses) earnings from other (2 ) 1 (3 ) 1 Earnings from equity method investments $ 14,426 $ 9,715 $ 57,051 $ 37,857 The following table details the components of the cash distributions from the Company's respective equity method investments included in the Condensed Consolidated Statements of Cash Flows . Distributions from equity method investees are reported in the Condensed Consolidated Statements of Cash Flows as " Distributions from equity method investees, return on investment " within Operating cash flows until such time as the carrying value in an equity method investee company is reduced to zero; thereafter, such distributions are reported as " Distributions from equity method investees in excess of cumulative earnings " within Investing cash flows. Nine Months Ended September 30, (in thousands) 2019 2018 Distributions from equity method investees, return on investment Tinuum Group $ 50,256 $ — Tinuum Services 6,550 4,000 $ 56,806 $ 4,000 Distributions from equity method investees in excess of investment basis Tinuum Group $ — $ 33,575 $ — $ 33,575

Debt Obligations

Debt Obligations	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt Obligations	Debt Obligations As of (in thousands) September 30, 2019 December 31, 2018 Senior Term Loan due December 2021, related party $ 46,000 $ 70,000 Less: net unamortized debt issuance costs (1,380 ) (1,990 ) Less: net unamortized debt discount (1,338 ) (2,052 ) Senior Term Loan due December 2021, net 43,282 65,958 Finance lease obligations (1) 7,066 8,167 50,348 74,125 Less: Current maturities (24,072 ) (24,067 ) Total long-term debt $ 26,276 $ 50,058 (1) As of December 31, 2018, obligations related to capital lease obligations as defined in ASC 840. Senior Term Loan On December 7, 2018, the Company, and ADA-ES, Inc. ("ADA"), a wholly-owned subsidiary, and certain other subsidiaries of the Company as guarantors, The Bank of New York Mellon as administrative agent, and Apollo Credit Strategies Master Fund Ltd and Apollo A-N Credit Fund (Delaware) L.P. (collectively "Apollo"), affiliates of a beneficial owner of greater than five percent of the Company's common stock and a related party, entered into the Senior Term Loan in the amount of $70.0 million less original issue discount of $2.1 million . Proceeds from the Senior Term Loan were used to fund the Carbon Solutions Acquisition as disclosed in Note 2 . The Company also paid debt issuance costs of $2.0 million related to the Senior Term Loan. The Senior Term Loan has a term of 36 months and bears interest at a rate equal to 3-month LIBOR (subject to a 1.5% floor) + 4.75% per annum, which is adjusted quarterly to the current 3-month LIBOR rate, and interest is payable quarterly in arrears. Quarterly principal payments of $6.0 million were required beginning in March 2019, and the Company may prepay the Senior Term Loan at any time without penalty. The Senior Term Loan is secured by substantially all of the assets of the Company, including the cash flows from Tinuum Group and Tinuum Services (collectively, the "Tinuum Entities"), but excluding the Company's equity interests in the Tinuum entities. The Senior Term Loan includes, among others, the following covenants: (1) Beginning December 31, 2018 and as of the end of each fiscal quarter thereafter, the Company must maintain a minimum cash balance of $5.0 million and shall not permit "expected future net cash flows from the refined coal business" (as defined in the Senior Term Loan) to be less than 1.75 times the outstanding principal amount of the Senior Term Loan; (2) Beginning in January 2019, annual collective dividends and buybacks of Company shares in an aggregate amount, not to exceed $30.0 million , is permitted so long as (a) no default or event of default exists under the Senior Term Loan and (b) expected future net cash flows from the refined coal business as of the end of the most recent fiscal quarter exceed $100.0 million . Line of Credit On September 30, 2018, ADA, as borrower, the Company, as guarantor, and a bank (the "Lender") entered into an amendment (the "Twelfth Amendment") to the 2013 Loan and Security Agreement (the "Line of Credit"). The Twelfth Amendment decreased the borrowing availability of the Line of Credit to $5.0 million due to decreased collateral requirements, extended the maturity date of the Line of Credit to September 30, 2020 and permitted the Line of Credit to be used as collateral (in place of restricted cash) for letters of credit ("LC's") up to $5.0 million related to equipment projects and certain other agreements. Under the Twelfth Amendment, there was no minimum balance requirement based on the Company meeting certain conditions and maintaining minimum trailing twelve-month EBITDA (earnings before interest, taxes, depreciation and amortization), as previously defined in the "Eleventh Amendment" to the Line of Credit, of $24.0 million . On December 7, 2018, ADA, as borrower, the Company, as guarantor, and the Lender entered into an amendment to the Line of Credit, which provided, among other things, for ADA to be able to enter into the Senior Term Loan as a guarantor so long as the principal amount of the Senior Term Loan did not exceed $70.0 million . Additionally, the financial covenants in the Line of Credit were amended and restated to be consistent with the aforementioned Senior Term Loan covenants, including maintaining a minimum cash balance of $5.0 million . As of September 30, 2019 , there were no outstanding borrowings under the Line of Credit.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases The financial statement impact from the adoption of ASC 842 as of January 1, 2019 is due to recording ROU assets and related lease liabilities for operating lease commitments that were outstanding as of December 31, 2018. The Company has elected the transitional practical expedients allowed under ASC 842, which include among other things that the Company need not reassess: (1) whether any existing contracts are or contain leases, inclusive of land easements; (2) the lease classification or lease term for existing leases; and (3) initial direct costs for any existing leases. In addition, the Company has elected for all classes of underlying assets the practical expedient to not separate nonlease components from lease components and to account for each separate lease component and the nonlease components associated with that lease component as a single lease component. ASC 842 defines a lease as a contract, or part of a contract, that conveys the right to control the use of an identified asset for a period of time in exchange for consideration. Control over the use of an identified asset means that an entity has both the right to obtain substantially all of the economic benefits from the use of an identified asset and the right to direct the use of that identified asset. The determination of whether a contract contains a lease may require significant assumptions and judgments. Historically, Carbon Solutions has used leasing to fund the majority of its capital needs for mining and manufacturing equipment. As of September 30, 2019 , the Company has obligations under finance and operating leases in the amounts of $7.1 million and $5.9 million , respectively. ROU assets under finance leases are mining equipment used at the Company’s lignite mine, which provides the key raw materials for manufacturing the Company’s products. ROU assets under operating leases are primarily plant equipment used at the Company’s manufacturing facility, but also include other office equipment, vehicles and office facilities. As of September 30, 2019 , the Company has ROU assets, net of accumulated amortization, under finance leases and operating leases of $6.4 million and $5.9 million , respectively. Certain of the finance and operating leases have options permitting renewals for additional periods and buy-out options. Renewal and buy-out options for applicable leases have not been included in the measurement of the respective lease liabilities as the Company is not reasonably certain that it will exercise the respective option or the lessor does not have an exclusive right to exercise the option. Variable lease payments represent payments made by a lessee for the right to use an underlying asset that vary because of changes in facts or circumstances occurring after the commencement date of a lease other than the passage of time. Variable lease payments that are based on an index or rate, calculated by using the index or rate that exists on the lease commencement date, are included in the measurement of a lease liability. Certain of the Company’s operating leases for office facilities contain variable lease components that are not based on an index or rate, and the Company recognizes these payments as lease expense in the period in which the obligation for those payments is incurred. The Company calculates lease liabilities based on the present value of lease payments discounted by the rate implicit in the lease or, if not readily determinable, the Company’s incremental borrowing rate. The Company records lease liabilities and related ROU assets for all leases that have a term of greater than one year. For short-term leases (leases with terms of less than one year), the Company expenses lease payments on a straight-line basis over the lease term. Finance leases Leases classified as capital leases under ASC 840 and the related assets and liabilities were recorded and classified as finance leases as of January 1, 2019 based on their carrying values of $8.1 million and $8.2 million , respectively, as of December 31, 2018. ROU assets under finance leases and finance lease liabilities are included in Property, plant and equipment and Current portion and Long-term portion of borrowings, respectively, in the Condensed Consolidated Balance Sheet as of September 30, 2019 . Finance lease liabilities are subsequently measured by increasing the carrying amount to reflect interest expense on the finance lease liability and reducing the carrying amount of the lease liability to reflect lease payments made during the period. Interest on finance lease liabilities is determined in each period during the lease term as the amount that produces a constant periodic discount rate on the remaining balance of the lease liability. ROU assets under finance leases are amortized over the remaining lease term on a straight-line basis. Interest expense related to finance lease liabilities and amortization of ROU assets under finance leases are included in Interest expense and Depreciation, amortization, depletion and accretion, respectively, in the Condensed Consolidated Statement of Operations for the three and nine months ended September 30, 2019 . Operating leases Operating lease liabilities as of January 1, 2019 were calculated at the present value, using a discount rate of the lease, of the remaining minimum rental payments (as defined under ASC 840). As the rate implicit in all of the operating leases was not readily determinable, the Company determined its discount rate as of January 1, 2019 based on an estimate of its incremental borrowing rate. This rate was based on the Company’s effective borrowing rate on the Senior Term Loan, considering the collateral requirements contained therein, in effect as of January 1, 2019. ROU assets under operating leases as of January 1, 2019 were determined as the calculated value of the operating lease liabilities less accrued lease payments and accrued lease incentives. As of December 31, 2018, the total amount of accrued lease payments and accrued lease incentives was approximately $0.1 million . ROU assets under operating leases and operating lease liabilities are included in Other long-term assets and Other liabilities and Other long-term liabilities, respectively, in the Condensed Consolidated Balance Sheet as of September 30, 2019 . Operating lease liabilities are subsequently measured at the present value of the lease payments not yet paid discounted using the discount rate for the lease established at the inception date of the lease (or January 1, 2019 for operating leases in effect as of December 31, 2018). ROU assets under operating leases are subsequently measured at the amounts of the related operating lease liability, adjusted for, as applicable, prepaid or accrued lease payments, the remaining balance of any lease incentives received, unamortized initial direct costs and impairment. Lease expense from operating leases is recognized as a single lease cost over the remaining lease term on a straight-line basis. Variable lease payments not included in operating lease liabilities are recognized as expense in the period in which the obligation for those payments is incurred. Lease expense for operating leases for the three and nine months ended September 30, 2019 was $1.1 million and $3.3 million , respectively, of which $1.0 million and $3.1 million , respectively is included in Consumables - cost of revenue, exclusive of depreciation and amortization, and $0.1 million and $0.3 million , respectively, is included in General and administrative in the Condensed Consolidated Statement of Operations for the three and nine months ended September 30, 2019 . In August 2019, the Company entered into a new lease agreement covering approximately twenty-one thousand square feet of office space for a term of 3.5 years and recorded a ROU asset of $1.2 million and a corresponding operating lease liability of $1.2 million . Lease financial information as of and for the three and nine months ended September 30, 2019 is provided in the following table: (in thousands) Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Finance lease cost: Amortization of right-of-use assets $ 1,277 $ 2,371 Interest on lease liabilities 82 270 Operating lease cost 908 2,764 Short-term lease cost 198 558 Variable lease cost (1) 52 227 Total lease cost $ 2,517 $ 6,190 Other Information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 270 Operating cash flows from operating leases $ 2,435 Financing cash flows from finance leases $ 1,016 Right-of-use assets obtained in exchange for new operating lease liabilities $ 1,309 Weighted-average remaining lease term - finance leases 4.4 years Weighted-average remaining lease term - operating leases 2.5 years Weighted-average discount rate - finance leases 6.1 % Weighted-average discount rate - operating leases 8.6 % (1) Primarily includes common area maintenance, property taxes and insurance payable to lessors. The following table summarizes the Company’s future lease payments under finance and operating leases as of September 30, 2019 : (in thousands) Operating Finance Total Lease Commitments 2019 (remaining three months) $ 873 $ 433 $ 1,306 2020 2,718 1,707 4,425 2021 2,035 1,802 3,837 2022 721 951 1,672 2023 359 951 1,310 Thereafter — 2,482 2,482 Total lease payments 6,706 8,326 15,032 Less: Imputed interest (769 ) (1,260 ) (2,029 ) Present value of lease payments $ 5,937 $ 7,066 $ 13,003 Disclosures under ASC 840 Rent expense for the three and nine months ended September 30, 2018 was $0.1 million and $0.2 million , respectively, and was included in General and administrative expense in the Condensed Consolidated Statement of Operations. As of December 31, 2018, mining equipment financed under capital leases in the amount of $8.1 million , net of accumulated amortization of $0.1 million , was included in Property, plant and equipment in the Condensed Consolidated Balance Sheet. The following table summarizes the Company’s future minimum non-cancellable lease payments due under capital and operating leases as of December 31, 2018: (in thousands) Operating Capital 2019 $ 3,619 $ 1,749 2020 2,273 1,707 2021 1,632 1,802 2022 310 951 2023 221 951 Thereafter — 2,482 Total minimum lease payments $ 8,055 9,642 Less: Imputed interest (1,475 ) Present value of minimum lease payments $ 8,167
Leases	Leases The financial statement impact from the adoption of ASC 842 as of January 1, 2019 is due to recording ROU assets and related lease liabilities for operating lease commitments that were outstanding as of December 31, 2018. The Company has elected the transitional practical expedients allowed under ASC 842, which include among other things that the Company need not reassess: (1) whether any existing contracts are or contain leases, inclusive of land easements; (2) the lease classification or lease term for existing leases; and (3) initial direct costs for any existing leases. In addition, the Company has elected for all classes of underlying assets the practical expedient to not separate nonlease components from lease components and to account for each separate lease component and the nonlease components associated with that lease component as a single lease component. ASC 842 defines a lease as a contract, or part of a contract, that conveys the right to control the use of an identified asset for a period of time in exchange for consideration. Control over the use of an identified asset means that an entity has both the right to obtain substantially all of the economic benefits from the use of an identified asset and the right to direct the use of that identified asset. The determination of whether a contract contains a lease may require significant assumptions and judgments. Historically, Carbon Solutions has used leasing to fund the majority of its capital needs for mining and manufacturing equipment. As of September 30, 2019 , the Company has obligations under finance and operating leases in the amounts of $7.1 million and $5.9 million , respectively. ROU assets under finance leases are mining equipment used at the Company’s lignite mine, which provides the key raw materials for manufacturing the Company’s products. ROU assets under operating leases are primarily plant equipment used at the Company’s manufacturing facility, but also include other office equipment, vehicles and office facilities. As of September 30, 2019 , the Company has ROU assets, net of accumulated amortization, under finance leases and operating leases of $6.4 million and $5.9 million , respectively. Certain of the finance and operating leases have options permitting renewals for additional periods and buy-out options. Renewal and buy-out options for applicable leases have not been included in the measurement of the respective lease liabilities as the Company is not reasonably certain that it will exercise the respective option or the lessor does not have an exclusive right to exercise the option. Variable lease payments represent payments made by a lessee for the right to use an underlying asset that vary because of changes in facts or circumstances occurring after the commencement date of a lease other than the passage of time. Variable lease payments that are based on an index or rate, calculated by using the index or rate that exists on the lease commencement date, are included in the measurement of a lease liability. Certain of the Company’s operating leases for office facilities contain variable lease components that are not based on an index or rate, and the Company recognizes these payments as lease expense in the period in which the obligation for those payments is incurred. The Company calculates lease liabilities based on the present value of lease payments discounted by the rate implicit in the lease or, if not readily determinable, the Company’s incremental borrowing rate. The Company records lease liabilities and related ROU assets for all leases that have a term of greater than one year. For short-term leases (leases with terms of less than one year), the Company expenses lease payments on a straight-line basis over the lease term. Finance leases Leases classified as capital leases under ASC 840 and the related assets and liabilities were recorded and classified as finance leases as of January 1, 2019 based on their carrying values of $8.1 million and $8.2 million , respectively, as of December 31, 2018. ROU assets under finance leases and finance lease liabilities are included in Property, plant and equipment and Current portion and Long-term portion of borrowings, respectively, in the Condensed Consolidated Balance Sheet as of September 30, 2019 . Finance lease liabilities are subsequently measured by increasing the carrying amount to reflect interest expense on the finance lease liability and reducing the carrying amount of the lease liability to reflect lease payments made during the period. Interest on finance lease liabilities is determined in each period during the lease term as the amount that produces a constant periodic discount rate on the remaining balance of the lease liability. ROU assets under finance leases are amortized over the remaining lease term on a straight-line basis. Interest expense related to finance lease liabilities and amortization of ROU assets under finance leases are included in Interest expense and Depreciation, amortization, depletion and accretion, respectively, in the Condensed Consolidated Statement of Operations for the three and nine months ended September 30, 2019 . Operating leases Operating lease liabilities as of January 1, 2019 were calculated at the present value, using a discount rate of the lease, of the remaining minimum rental payments (as defined under ASC 840). As the rate implicit in all of the operating leases was not readily determinable, the Company determined its discount rate as of January 1, 2019 based on an estimate of its incremental borrowing rate. This rate was based on the Company’s effective borrowing rate on the Senior Term Loan, considering the collateral requirements contained therein, in effect as of January 1, 2019. ROU assets under operating leases as of January 1, 2019 were determined as the calculated value of the operating lease liabilities less accrued lease payments and accrued lease incentives. As of December 31, 2018, the total amount of accrued lease payments and accrued lease incentives was approximately $0.1 million . ROU assets under operating leases and operating lease liabilities are included in Other long-term assets and Other liabilities and Other long-term liabilities, respectively, in the Condensed Consolidated Balance Sheet as of September 30, 2019 . Operating lease liabilities are subsequently measured at the present value of the lease payments not yet paid discounted using the discount rate for the lease established at the inception date of the lease (or January 1, 2019 for operating leases in effect as of December 31, 2018). ROU assets under operating leases are subsequently measured at the amounts of the related operating lease liability, adjusted for, as applicable, prepaid or accrued lease payments, the remaining balance of any lease incentives received, unamortized initial direct costs and impairment. Lease expense from operating leases is recognized as a single lease cost over the remaining lease term on a straight-line basis. Variable lease payments not included in operating lease liabilities are recognized as expense in the period in which the obligation for those payments is incurred. Lease expense for operating leases for the three and nine months ended September 30, 2019 was $1.1 million and $3.3 million , respectively, of which $1.0 million and $3.1 million , respectively is included in Consumables - cost of revenue, exclusive of depreciation and amortization, and $0.1 million and $0.3 million , respectively, is included in General and administrative in the Condensed Consolidated Statement of Operations for the three and nine months ended September 30, 2019 . In August 2019, the Company entered into a new lease agreement covering approximately twenty-one thousand square feet of office space for a term of 3.5 years and recorded a ROU asset of $1.2 million and a corresponding operating lease liability of $1.2 million . Lease financial information as of and for the three and nine months ended September 30, 2019 is provided in the following table: (in thousands) Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Finance lease cost: Amortization of right-of-use assets $ 1,277 $ 2,371 Interest on lease liabilities 82 270 Operating lease cost 908 2,764 Short-term lease cost 198 558 Variable lease cost (1) 52 227 Total lease cost $ 2,517 $ 6,190 Other Information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 270 Operating cash flows from operating leases $ 2,435 Financing cash flows from finance leases $ 1,016 Right-of-use assets obtained in exchange for new operating lease liabilities $ 1,309 Weighted-average remaining lease term - finance leases 4.4 years Weighted-average remaining lease term - operating leases 2.5 years Weighted-average discount rate - finance leases 6.1 % Weighted-average discount rate - operating leases 8.6 % (1) Primarily includes common area maintenance, property taxes and insurance payable to lessors. The following table summarizes the Company’s future lease payments under finance and operating leases as of September 30, 2019 : (in thousands) Operating Finance Total Lease Commitments 2019 (remaining three months) $ 873 $ 433 $ 1,306 2020 2,718 1,707 4,425 2021 2,035 1,802 3,837 2022 721 951 1,672 2023 359 951 1,310 Thereafter — 2,482 2,482 Total lease payments 6,706 8,326 15,032 Less: Imputed interest (769 ) (1,260 ) (2,029 ) Present value of lease payments $ 5,937 $ 7,066 $ 13,003 Disclosures under ASC 840 Rent expense for the three and nine months ended September 30, 2018 was $0.1 million and $0.2 million , respectively, and was included in General and administrative expense in the Condensed Consolidated Statement of Operations. As of December 31, 2018, mining equipment financed under capital leases in the amount of $8.1 million , net of accumulated amortization of $0.1 million , was included in Property, plant and equipment in the Condensed Consolidated Balance Sheet. The following table summarizes the Company’s future minimum non-cancellable lease payments due under capital and operating leases as of December 31, 2018: (in thousands) Operating Capital 2019 $ 3,619 $ 1,749 2020 2,273 1,707 2021 1,632 1,802 2022 310 951 2023 221 951 Thereafter — 2,482 Total minimum lease payments $ 8,055 9,642 Less: Imputed interest (1,475 ) Present value of minimum lease payments $ 8,167

Revenues

Revenues	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenues	Revenues Contract Assets and Liabilities Contract assets are comprised of unbilled receivables and are included in Receivables, net in the Condensed Consolidated Balance Sheet. Unbilled receivables represent a conditional right to consideration in exchange for goods or services transferred to a customer. Trade receivables represent an unconditional right to consideration in exchange for goods or services transferred to a customer. The Company invoices its customers in accordance with the terms of the contract. Credit terms are generally net 30 from the date of invoice. The timing between the satisfaction of performance obligations and when payment is due from the customer is generally not significant. The Company records allowances for doubtful trade receivables when it is probable that the balances will not be collected. Contract liabilities are comprised of deferred revenue, which represents an obligation to transfer goods or services to a customer for which the Company has received consideration from the customer and, if deliverable within one year or less, is included in Other current liabilities in the Condensed Consolidated Balance Sheet and, if deliverable outside of one year, is included in Other long-term liabilities in the Condensed Consolidated Balance Sheet. Trade receivables, net The following table shows the components of Trade receivables, net: As of (in thousands) September 30, 2019 December 31, 2018 Trade receivables $ 7,338 $ 10,121 Less: Allowance for doubtful accounts (567 ) (567 ) Trade receivables, net $ 6,771 $ 9,554 For the three and nine months ended September 30, 2019 , the Company recognized zero provision for bad debt expense, respectively. Disaggregation of Revenue During the three and nine months ended September 30, 2019 and 2018 , all performance obligations related to revenues recognized were satisfied at a point in time. The Company disaggregates its revenues by major components as well as between its two reportable segments, which are further discussed in Note 13 to the Condensed Consolidated Financial Statements. The following tables disaggregate revenues by major component for the three and nine months ended September 30, 2019 and 2018 (in thousands): Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Segment Segment PGI RC Other Total PGI RC Other Total Revenue component Consumables $ 14,010 $ — $ 738 $ 14,748 $ 39,612 $ — $ 1,631 $ 41,243 License royalties, related party — 4,385 — 4,385 — 12,796 — 12,796 Revenues from customers 14,010 4,385 738 19,133 39,612 12,796 1,631 54,039 Earnings from equity method investments — 14,426 — 14,426 — 57,051 — 57,051 Total revenues from customers and earnings from equity method investments $ 14,010 $ 18,811 $ 738 $ 33,559 $ 39,612 $ 69,847 $ 1,631 $ 111,090 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Segment Segment PGI RC Total PGI RC Total Revenue component Consumables $ 1,043 $ — $ 1,043 $ 2,390 $ — $ 2,390 License royalties, related party — 4,104 4,104 — 10,857 10,857 Other — — — 72 — 72 Revenues from customers 1,043 4,104 5,147 2,462 10,857 13,319 Earnings from equity method investments — 9,715 9,715 — 37,857 37,857 Total revenues from customers and earnings from equity method investments $ 1,043 $ 13,819 $ 14,862 $ 2,462 $ 48,714 $ 51,176

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings The Company is from time to time subject to, and is presently involved in, various pending or threatened legal actions and proceedings, including those that arise in the ordinary course of its business. Such matters are subject to many uncertainties and to outcomes, the financial impacts of which are not predictable with assurance and that may not be known for extended periods of time. The Company records a liability in its consolidated financial statements for costs related to claims, settlements, and judgments where management has assessed that a loss is probable and an amount can be reasonably estimated. There were no significant legal proceedings as of September 30, 2019 . Restricted Cash As of September 30, 2019 and December 31, 2018 , the Company had long-term restricted cash of $5.0 million and $5.2 million , respectively, which primarily consisted of minimum cash balance requirements under the Senior Term Loan. As of September 30, 2019 and December 31, 2018 , the Company had short-term restricted cash of zero and $0.1 million , respectively, related to other commitments. Tinuum Group The Company also has certain limited obligations contingent upon future events in connection with the activities of Tinuum Group. The Company, NexGen and two entities affiliated with NexGen have provided an affiliate of the Goldman Sachs Group, Inc. with limited guaranties (the "Tinuum Group Party Guaranties") related to certain losses it may suffer as a result of inaccuracies or breach of representations and covenants. The Company also is a party to a contribution agreement with NexGen under which any party called upon to pay on a Tinuum Group Party Guaranty is entitled to receive contributions from the other party equal to 50% of the amount paid. No liability or expense provision has been recorded by the Company related to this contingent obligation as the Company believes that it is not probable that a loss will occur with respect to Tinuum Group Party Guaranties.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Stock Repurchase Programs In November 2018, the Company's Board of Directors (the "Board") authorized the Company to purchase up to $20.0 million of its outstanding common stock. This stock repurchase program will remain in effect until December 31, 2019 unless otherwise modified by the Board. Previously, the Board had authorized the Company to purchase up to $20.0 million of its outstanding common stock under a separate repurchase program that was in effect until July 31, 2018. For the three and nine months ended September 30, 2019 , under the respective stock repurchase program authorized by the Board, the Company purchased 8,152 and 256,743 shares of its common stock for cash of $0.1 million and $2.9 million , respectively, inclusive of commissions and fees. For the three and nine months ended September 30, 2018 , under the respective stock repurchase program authorized by the Board, the Company purchased 186,212 and 1,011,630 shares of its common stock for cash of $2.1 million and $11.2 million , respectively, inclusive of commissions and fees. Of these amounts, $2.1 million and $4.3 million were purchased in single blocks through privately negotiated transactions for the three and nine months ended September 30, 2018 , respectively. Quarterly Cash Dividend Dividends per share declared by the Board, and paid quarterly on all outstanding shares of common stock during the three and nine months ended September 30, 2019 and 2018 were as follows: 2019 2018 Per share Date paid Per share Date paid Dividends declared during quarter ended: March 31 $ 0.25 March 7, 2019 $ 0.25 March 8, 2018 June 30 $ 0.25 June 7, 2019 $ 0.25 June 8, 2018 September 30 $ 0.25 September 6, 2019 $ 0.25 September 6, 2018 $ 0.75 $ 0.75 A portion of the dividends declared remains accrued subsequent to the payment dates and represents dividends accumulated on nonvested shares of common stock held by employees and directors of the Company that contain forfeitable dividend rights that are not payable until the underlying shares of common stock vest. These amounts are included in both Other current liabilities and Other long-term liabilities on the Condensed Consolidated Balance Sheet as of September 30, 2019 . Tax Asset Protection Plan U.S. federal income tax rules, and Section 382 of the Internal Revenue Code in particular, could substantially limit the use of net operating losses and other tax assets if the Company experiences an "ownership change" (as defined in the Internal Revenue Code). In general, an ownership change occurs if there is a cumulative change in the ownership of the Company by "5 percent stockholders" that exceeds 50 percentage points over a rolling three-year period. On May 5, 2017, the Board approved the declaration of a dividend of rights to purchase Series B Junior Participating Preferred Stock for each outstanding share of common stock as part of a tax asset protection plan (the "Tax Asset Protection Plan") designed to protect the Company’s ability to utilize its net operating losses and tax credits. The Tax Asset Protection Plan is intended to act as a deterrent to any person acquiring beneficial ownership of 4.99% or more of the Company’s outstanding common stock. On April 6, 2018, the Board approved the First Amendment to the Tax Asset Protection Plan (the "First Amendment") that amends the Tax Asset Protection Plan dated May 5, 2017. The First Amendment amended the definition of "Final Expiration Date" under the Tax Asset Protection Plan to extend the duration of the TAPP and makes associated changes in connection therewith. At the Company's 2018 annual meeting of stockholders, the Company's stockholders approved the First Amendment, thus the Final Expiration Date will be the close of business on December 31, 2019, which was subsequently extended, as described below. On April 5, 2019, the Board approved the Second Amendment to the Tax Asset Protection Plan (the "Second Amendment") that amends the Tax Asset Protection Plan dated May 5, 2017, as amended by the First Amendment to Tax Asset Protection Plan, dated April 6, 2018 (the “TAPP”) between the Company and the Rights Agent. The Second Amendment amends the definition of the “Final Expiration Date” under the TAPP to extend the duration of the TAPP and makes associated changes in connection therewith. At the Company's 2019 annual meeting of stockholders, the Company's stockholders approved the Second Amendment, thus the Final Expiration Date will be the close of business on December 31, 2020.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company grants equity-based awards to employees, non-employee directors, and consultants that may include, but are not limited to, RSA's, restricted stock units ("RSU's") and stock options. Stock-based compensation expense related to manufacturing employees and administrative employees is included within the Cost of goods sold and Payroll and benefits line items, respectively, in the Condensed Consolidated Statements of Operations . Stock-based compensation expense related to non-employee directors and consultants is included within the General and administrative line item in the Condensed Consolidated Statements of Operations . Total stock-based compensation expense for the three and nine months ended September 30, 2019 and 2018 was as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 RSA expense $ 468 $ 919 $ 1,326 $ 1,871 Stock option expense — — — 58 Total stock-based compensation expense $ 468 $ 919 $ 1,326 $ 1,929 The amount of unrecognized compensation cost as of September 30, 2019 , and the expected weighted-average period over which the cost will be recognized is as follows: As of September 30, 2019 (in thousands) Unrecognized Compensation Cost Expected Weighted- RSA expense $ 3,146 1.67 Total unrecognized stock-based compensation expense $ 3,146 1.67 Restricted Stock Restricted stock is typically granted with vesting terms of three years. The fair value of RSA's and RSU's is determined based on the closing price of the Company’s common stock on the authorization date of the grant multiplied by the number of shares subject to the stock award. Compensation expense for RSA's is generally recognized on a straight-line basis over the entire vesting period. Compensation expense for RSU's is generally recognized on a straight-line basis over the service period of the award. A summary of RSA and RSU activity under the Company's various stock compensation plans for the nine months ended September 30, 2019 is presented below: Restricted Stock Weighted-Average Grant Date Fair Value (in thousands, except for share and per share amounts) Awards Units RSA's RSU's Non-vested at January 1, 2019 280,852 20,000 $ 9.92 $ 10.52 Granted 275,983 — $ 11.07 $ — Vested (84,156 ) — $ 9.74 $ — Forfeited (3,498 ) — $ 10.96 $ — Non-vested at September 30, 2019 469,181 20,000 $ 10.62 $ 10.52 Stock Options Stock options generally vest over three years or upon satisfaction of performance-based conditions and have a contractual limit of five years from the date of grant to exercise. The fair value of stock options granted is determined on the date of grant using the Black-Scholes option pricing model and the related expense is recognized on a straight-line basis over the entire vesting period. A summary of stock option activity for the nine months ended September 30, 2019 is presented below: Number of Options Weighted-Average Aggregate Intrinsic Value (in thousands) Weighted-Average Options outstanding, January 1, 2019 529,780 $ 12.23 Options granted — — Options exercised (185,332 ) 9.50 Options expired / forfeited (20,000 ) 20.07 Options outstanding, September 30, 2019 324,448 $ 13.31 $ 497 0.74 Options exercisable, September 30, 2019 324,448 $ 13.31 $ 497 0.74 The Company did no t receive cash from the exercise of stock options during the three months ended September 30, 2019 as 149,715 shares were withheld as payment of the exercise price. The total intrinsic value of options exercised during the three months ended September 30, 2019 was $0.4 million .

Supplemental Financial Informat

Supplemental Financial Information	9 Months Ended
	Sep. 30, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Supplemental Financial Information	Supplemental Financial Information Supplemental Balance Sheet Information The following table summarizes the components of Prepaid expenses and other assets and Other long-term assets, net as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Prepaid expenses and other assets: Prepaid expenses $ 1,635 $ 1,233 Prepaid income taxes 2,753 2,940 Other 1,682 1,397 $ 6,070 $ 5,570 Other long-term assets, net: Highview Investment $ 552 $ 552 Spare parts 3,325 3,278 Mine development costs, net 4,672 2,531 Mine reclamation asset, net 2,291 — Prepaid royalty expense, long-term 955 955 Right of use assets, operating leases, net 5,894 — Other long-term assets 674 677 $ 18,363 $ 7,993 Spare parts include critical spares required to support plant operations. Parts and supply costs are determined using the lower of cost or estimated replacement cost. Parts are recorded as maintenance expenses in the period in which they are consumed. Mine development costs include acquisition costs, the cost of other development work and mitigation costs related to the Company's mining operations which are depleted over the estimated life of the related mine reserves, which is 18 years. The Company performs an evaluation of the recoverability of the carrying value of mine development costs to determine if facts and circumstances indicate that their carrying value may be impaired and if any adjustment is warranted. There were no indicators of impairment as of September 30, 2019 . Mine reclamation asset represents an asset retirement obligation asset and is depreciated over the estimated life of the mine, which is 18 years . The Company holds a long-term investment (the "Highview Investment") in Highview Enterprises Limited ("Highview"), a London, England based developmental stage company specializing in power storage. In November 2014, the Company acquired an 8% ownership interest in the common stock of Highview for $2.8 million in cash. The Company accounts for the Highview Investment as an investment recorded at cost, less impairment, plus or minus observable changes in price for identical or similar investments of the same issuer. The Highview Investment is evaluated for indicators of impairment such as an event or change in circumstances that may have a significant adverse effect on the fair value of the investment. There were no changes to the carrying value of the Highview Investment for the three and nine months ended September 30, 2019 as there were no indicators of impairment or observable price changes for equity issued by Highview. The following table details the components of Other current liabilities and Other long-term liabilities as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Other current liabilities: Current portion of operating lease obligations $ 2,605 $ — Accrued interest 339 407 Income and other taxes payable 420 479 Other 923 1,252 $ 4,287 $ 2,138 Other long-term liabilities: Operating lease obligations, long-term $ 3,332 $ — Mine reclamation liability 2,540 624 Other long-term liabilities 190 316 $ 6,062 $ 940 Supplemental Condensed Consolidated Statements of Operations Information The following table details the components of Interest expense in the Condensed Consolidated Statements of Operations: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Interest on Senior Term Loan $ 940 $ — $ 3,344 $ — Debt discount and debt issuance costs 473 — 1,324 — 453A interest 234 388 882 1,128 Other 82 11 270 19 $ 1,729 $ 399 $ 5,820 $ 1,147

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three and nine months ended September 30, 2019 and 2018 , the Company's income tax expense and effective tax rates based on forecasted pre-tax income were: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except for rate) 2019 2018 2019 2018 Income tax expense $ 6,595 $ 3,931 $ 14,928 $ 5,151 Effective tax rate 63 % 42 % 36 % 15 % The effective tax rate for the three and nine months ended September 30, 2019 was different from the federal statutory rate due to increases of $4.8 million and $3.6 million , respectively, in the valuation allowance on deferred tax assets. These charges were a result of a reduction in forecasts as of September 30, 2019 of future years' taxable income. In addition, the effective rate for both the three and nine months ended September 30, 2019 was increased by state income tax expense, net of federal benefit. The Company assesses the valuation allowance recorded against deferred tax assets at each reporting date. The determination of whether a valuation allowance for deferred tax assets is appropriate requires the evaluation of positive and negative evidence that can be objectively verified. Consideration must be given to all sources of taxable income available to realize the deferred tax asset, including, as applicable, the future reversal of existing temporary differences, future taxable income forecasts exclusive of the reversal of temporary differences and carryforwards, taxable income in carryback years and tax planning strategies. In estimating income taxes, the Company assesses the relative merits and risks of the appropriate income tax treatment of transactions taking into account statutory, judicial, and regulatory guidance.

Business Segment Information

Business Segment Information	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Business Segment Information	Business Segment Information Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by a company's chief operating decision maker ("CODM"), or a decision-making group, in deciding how to allocate resources and in assessing financial performance. As of September 30, 2019 , the Company's CODM was the Company's CEO. The Company's operating and reportable segments are identified by products and services provided. As of September 30, 2019 , the Company has two reportable segments: (1) Refined Coal ("RC"); and (2) Power Generation and Industrials ("PGI"). The business segment measurements provided to and evaluated by the CODM are computed in accordance with the principles listed below: • The accounting policies of the operating segments are the same as those described in the summary of significant accounting policies in the 2018 Form 10-K. • Segment revenues include equity method earnings and losses from the Company's equity method investments. • Segment operating income (loss) includes segment revenues and allocation of certain "Corporate general and administrative expenses," which include Payroll and benefits , Legal and professional fees and General and administrative . • RC segment operating income includes interest expense directly attributable to the RC segment. As of September 30, 2019 and December 31, 2018 , substantially all of the Company's material assets are located in the U.S. and all significant customers are U.S. companies. The following table presents the Company's operating segment results for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Revenues: Refined Coal: Earnings in equity method investments $ 14,426 $ 9,715 $ 57,051 $ 37,857 License royalties, related party 4,385 4,104 12,796 10,857 18,811 13,819 69,847 48,714 Power Generation and Industrials: Consumables 14,010 1,043 39,612 2,390 Other — — — 72 14,010 1,043 39,612 2,462 Total segment reporting revenues 32,821 14,862 109,459 51,176 Adjustments to reconcile to reported revenues: Earnings in equity method investments (14,426 ) (9,715 ) (57,051 ) (37,857 ) Corporate and other 738 — 1,631 — Total reported revenues $ 19,133 $ 5,147 $ 54,039 $ 13,319 Segment operating income (loss): Refined Coal (1) $ 18,158 $ 12,798 $ 68,137 $ 45,775 Power Generation and Industrials (2) (977 ) (1,168 ) (8,301 ) (3,493 ) Total segment operating income $ 17,181 $ 11,630 $ 59,836 $ 42,282 (1) Included in RC segment operating income for the three and nine months ended September 30, 2019 and 2018 is 453A interest expense of $0.2 million and $0.9 million and $0.4 million and $1.1 million , respectively. (2) Included in PGI segment operating loss for the nine months ended September 30, 2019 was $4.7 million of costs recognized as a result of the step-up in inventory fair value recorded from the Carbon Solutions Acquisition. Also included in PGI segment operating loss for the three and nine months ended September 30, 2019 was $1.9 million and $4.5 million , respectively, of depreciation, amortization, and depletion expense on mine and plant long-lived assets. A reconciliation of reportable segment operating income to the Company's consolidated income before income tax expense is as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Total reported segment operating income $ 17,181 $ 11,630 $ 59,836 $ 42,282 Other operating loss (658 ) — (1,409 ) — 16,523 11,630 58,427 42,282 Adjustments to reconcile to income before income tax expense attributable to the Company: Corporate payroll and benefits (768 ) (957 ) (2,004 ) (3,054 ) Corporate legal and professional fees (1,737 ) (634 ) (5,254 ) (3,222 ) Corporate general and administrative (2,278 ) (658 ) (5,427 ) (2,483 ) Corporate depreciation and amortization (21 ) (23 ) (41 ) (97 ) Corporate interest (expense) income, net (1,413 ) (10 ) (4,668 ) (18 ) Other income (expense), net 212 86 334 199 Income before income tax expense $ 10,518 $ 9,434 $ 41,367 $ 33,607 Corporate general and administrative expenses include certain costs that benefit the business as a whole but are not directly related to one of the Company's segments. Such costs include, but are not limited to, accounting and human resources staff, information systems costs, legal fees, facility costs, audit fees and corporate governance expenses. A reconciliation of reportable segment assets to the Company's consolidated assets is as follows: As of (in thousands) September 30, December 31, Assets: Refined Coal (1) $ 49,055 $ 11,468 Power Generation and Industrials 82,121 85,786 Total segment assets 131,176 97,254 All Other and Corporate (2) 47,552 62,410 Consolidated $ 178,728 $ 159,664 (1) Includes $44.1 million and $6.6 million of investments in equity method investees, respectively. (2) Includes the Company's deferred tax assets.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value of financial instruments The carrying amounts of financial instruments, including cash, cash equivalents and restricted cash, accounts receivable, accounts payable and accrued expenses, approximate fair value due to the short maturity of these instruments. Accordingly, these instruments are not presented in the table below. The following table provides the estimated fair values of the remaining financial instruments: As of September 30, 2019 As of December 31, 2018 (in thousands) Carrying Value Fair Value Carrying Value Fair Value Financial Instruments: Highview Investment $ 552 $ 552 $ 552 $ 552 Highview Obligation $ 207 $ 207 $ 213 $ 213 Concentration of credit risk The Company's financial instruments that are exposed to concentrations of credit risk consist primarily of cash and cash equivalents. The Company holds cash and cash equivalents at three financial institutions as of September 30, 2019 . If an institution was unable to perform its obligations, the Company would be at risk regarding the amount of cash and investments in excess of the Federal Deposit Insurance Corporation limits (currently $250 thousand ) that would be returned to the Company. Assets and Liabilities Measured at Fair Value on a Recurring Basis As of September 30, 2019 and December 31, 2018 , the Company had no financial instruments carried and measured at fair value on a recurring basis. Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis The Company completed the Carbon Solutions Acquisition, in which the fair value of the purchase consideration totaled $66.5 million . The Company's allocation of purchase consideration to the estimated fair values of the assets acquired and liabilities assumed is disclosed in Note 2 . The fair value measurements represent Level 3 measurements as they are based on significant inputs not observable in the market.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2019
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring In December 2018, the Company recorded restructuring charges in connection with the departures of certain executives of Carbon Solutions in conjunction with the Carbon Solutions Acquisition. As part of the Carbon Solutions Acquisition, the Company also assumed a salary severance liability for an additional executive of Carbon Solutions in the amount of $0.6 million . Additionally, the Company recorded restructuring charges in 2018 in connection with a reduction in force that commenced in May 2018 as part of the Company's further alignment of the business with strategic objectives, which included the departure of certain executive officers. These charges related to cash severance arrangements with departing employees and executives, as well as stock-based compensation charges related to the acceleration of vesting of certain stock awards. There were no material restructuring activities during the three and nine months ended September 30, 2019 . A summary of the net pretax charges, incurred by segment, for the three and nine months ended September 30, 2018 is as follows: Pretax Charge (in thousands, except employee data) Approximate Number of Employees Refined Coal (1) Power Generation and Industrials (1) All Other and Corporate (1) Total Three Months Ended September 30, 2018 Restructuring charges 7 $ 168 $ 500 $ 434 $ 1,102 Changes in estimates — — — — Total pretax charge, net of reversals $ 168 $ 500 $ 434 $ 1,102 Nine Months Ended September 30, 2018 Restructuring charges 13 $ 448 $ 996 $ 557 $ 2,001 Changes in estimates — — — — Total pretax charge, net of reversals $ 448 $ 996 $ 557 $ 2,001 (1) Restructuring charges were allocated consistent with the allocations made in Note 13 - Business Segment Information The following table summarizes the Company's change in restructuring accruals for the nine months ended September 30, 2019 : (in thousands) Employee Severance Remaining accrual as of December 31, 2018 $ 2,208 Expense provision 233 Cash payments and other (1,758 ) Change in estimates (104 ) Remaining accrual as of September 30, 2019 $ 579 Restructuring accruals are included within the Accrued payroll and related liabilities line item in the Condensed Consolidated Balance Sheets . Restructuring expenses are included within the Payroll and benefits line item in the Condensed Consolidated Statements of Operations .

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Unless disclosed elsewhere within the notes to the Condensed Consolidated Financial Statements, the following are the significant matters that occurred subsequent to September 30, 2019 . Dividends On November 12, 2019 , the Company's Board declared a quarterly dividend of $0.25 per share of common stock, which is payable on December 13, 2019 to stockholders of record as of the close of business on November 26, 2019 . Share repurchase program As disclosed in Note 9 , in November 2018, the Company's Board authorized the Company to purchase up to $20.0 million of its outstanding common stock. This stock repurchase program was to remain in effect until December 31, 2019 unless otherwise modified by the Board. As of September 30, 2019 , the Company had $2.9 million remaining under this program. In November 2019, the Board authorized an incremental $7.1 million to this stock repurchase program and provided that the program will remain in effect until all amounts are utilized or the program is otherwise modified by the Board.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	The accompanying Condensed Consolidated Financial Statements of ADES are unaudited and have been prepared in conformity with accounting principles generally accepted in the United States ("U.S. GAAP") and with Article 10 of Regulation S-X of the Securities and Exchange Commission. In compliance with those instructions, certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The unaudited Condensed Consolidated Financial Statements of ADES in this quarterly report ("Quarterly Report") are presented on a consolidated basis and include ADES and its wholly-owned subsidiaries (collectively, the "Company"). Also included within the unaudited Condensed Consolidated Financial Statements are the Company's unconsolidated equity investments; Tinuum Group, Tinuum Services, LLC ("Tinuum Services"), and GWN Manager, LLC ("GWN Manager"), which are accounted for under the equity method of accounting, and Highview Enterprises Limited (the "Highview Investment"), which is accounted for in accordance with U.S. GAAP applicable to equity investments that do not qualify for the equity method of accounting. Results of operations and cash flows for the interim periods are not necessarily indicative of the results that may be expected for the entire year. All significant intercompany transactions and accounts were eliminated for all periods presented in this Quarterly Report. In the opinion of management, these Condensed Consolidated Financial Statements include all normal and recurring adjustments considered necessary for a fair presentation of the results of operations, financial position, stockholders' equity and cash flows for the interim periods presented. These Condensed Consolidated Financial Statements of ADES should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 (the "2018 Form 10-K").
Earnings Per Share	Basic earnings per share is computed using the two-class method, which is an earnings allocation formula that determines earnings per share for common stock and any participating securities according to dividend and participating rights in undistributed earnings. The Company's restricted stock awards ("RSA's") granted prior to December 31, 2016 contain non-forfeitable rights to dividends or dividend equivalents and are deemed to be participating securities. RSA's granted subsequent to December 31, 2016 do not contain non-forfeitable rights to dividends and are not deemed to be participating securities. Under the two-class method, net income for the period is allocated between common stockholders and the holders of the participating securities based on the weighted-average number of common shares outstanding during the period, excluding participating, unvested RSA's ("common shares"), and the weighted-average number of participating unvested RSA's outstanding during the period, respectively. The allocated, undistributed income for the period is then divided by the weighted-average number of common shares and participating, unvested RSA's outstanding during the period to arrive at basic earnings per common share and participating security for the period, respectively. Pursuant to U.S. GAAP, the Company has elected not to separately present basic or diluted earnings per share attributable to participating securities in the Condensed Consolidated Statements of Operations. Diluted earnings per share is computed in a manner consistent with that of basic earnings per share, while considering other potentially dilutive securities. Potentially dilutive securities consist of both unvested, participating and non-participating RSA's, as well as outstanding options to purchase common stock ("Stock Options") and contingent performance stock units ("PSU's") (collectively, "Potential dilutive shares"). The dilutive effect, if any, for non-participating RSA's, Stock Options and PSU's is determined using the greater of dilution as calculated under the treasury stock method or the two-class method. Potential dilutive shares are excluded from diluted earnings per share when their effect is anti-dilutive. When there is a net loss for a period, all Potential dilutive shares are anti-dilutive and are excluded from the calculation of diluted loss per share for that period.
Use of Estimates	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. There have been no changes in the Company’s critical accounting estimates from those that were disclosed in the 2018 Form 10-K. Actual results could differ from these estimates.
Risks and Uncertainties	The Company’s earnings are significantly affected by equity earnings it receives from Tinuum Group. As of September 30, 2019 , Tinuum Group has 23 invested RC facilities of which 11 are leased to a single customer. A majority of these leases are periodically renewed and the loss of this single customer or material modification to the lease terms of these facilities by this customer would have a significant adverse impact on Tinuum Group's financial position, results of operations and cash flows, which in turn would have material adverse impact on the Company’s financial position, results of operations and cash flows. The Company's revenues, sales volumes, earnings and cash flows are significantly affected by prices of competing power generation sources such as natural gas and renewable energy. Low natural gas prices make it a competitive alternative to coal-fired power generation and therefore, coal consumption may be reduced, which reduces the demand for our products. In addition, coal consumption and demand for our products is also affected by the demand for electricity, which is higher in the warmer and colder months of the year. Abnormal temperatures during the summer and winter months may significantly reduce coal consumption and thus the demand for the Company's products. The Company's financial instruments that are exposed to concentrations of credit risk consist primarily of cash and cash equivalents. The Company holds cash and cash equivalents at three financial institutions as of September 30, 2019 . If an institution was unable to perform its obligations, the Company would be at risk regarding the amount of cash and investments in excess of the Federal Deposit Insurance Corporation limits (currently $250 thousand ) that would be returned to the Company.
Reclassifications	Certain balances have been reclassified from the prior year to conform to the current year presentation. No reclassifications have any impact to income before income taxes or net income.
New Accounting Guidance	Recently Adopted In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) ("ASU 2016-02"), which created ASC Topic 842 - Leases ("ASC 842"), requiring lessees to recognize a right of use asset and related lease liability for those leases classified as operating leases at the commencement date and have lease terms of more than 12 months. ASC 842 retains the distinction between finance leases (formerly defined as capital leases) and operating leases. On January 1, 2019, the Company adopted ASC 842 retrospectively beginning with the date of adoption. Under this adoption method, the application date is the beginning of the reporting period in which the Company first applies the provisions of ASC 842. Accordingly, the Company’s reporting for the comparative periods presented in the financial statements and related disclosures continues in accordance with legacy U.S. GAAP under ASC Topic 840 - Leases ("ASC 840"). The adoption of ASC 842 had no impact to the opening balance of Retained earnings. As of the adoption date, the Company recorded $7.0 million and $7.0 million of "right of use" ("ROU") assets and incremental lease liabilities, respectively. The cumulative effect of the change from the adoption of ASC 842 to the Consolidated Balance Sheet as of January 1, 2019 is shown in the table that follows: Balance as of Impact of Balance as of (in thousands) December 31, 2018 Adoption January 1, 2019 Balance Sheet Other long-term assets $ 7,993 $ 6,956 $ 14,949 Other liabilities $ 50,058 $ 3,085 $ 53,143 Other long-term liabilities $ 940 $ 3,871 $ 4,811 See Note 6 for additional disclosures required under ASC 842 in the year of adoption. As of January 1, 2019, Tinuum Group adopted ASU 2016-02 and ASU 2014-09 (Topic 606), Revenue from Contracts with Customers and related pronouncements ("ASC 606"). As a result of Tinuum Group’s adoption of these pronouncements, the Company recorded a cumulative effect increase of $28.8 million to Retained earnings as of January 1, 2019, based on the Company's ownership percentage of Tinuum Group's cumulative effect adjustment, and increased its investment balance in Tinuum Group in the amount of $37.2 million and established a deferred tax liability of $8.4 million . As a result of the increase in the investment balance in Tinuum Group, for the nine months ended September 30, 2019 , the Company recognized equity earnings in Tinuum Group based on its pro-rata share of Tinuum Group’s net income rather than based on cash distributions received as had been required in prior periods as a result of the cumulative cash distributions exceeding the cumulative pro-rata share of Tinuum Group's net income. Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). The main objective of ASU 2016-13 is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. To achieve this objective, the amendments in ASU 2016-13 replace the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those years, and must be adopted under a modified retrospective method approach. Entities may adopt ASU 2016-13 earlier as of the fiscal years beginning after December 15, 2018, including interim periods within those years. The Company is currently evaluating the provisions of this guidance and assessing its impact on the Company's financial statements and disclosures. The Company does not believe this standard will have a material impact on the Company's financial statements and disclosures. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement ("ASU 2018-13"). The amendments in ASU 2018-13 improve the effectiveness of fair value measurement disclosures and modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement ("Topic 820"), based on the concepts in FASB Concepts Statement, Conceptual Framework for Financial Reporting - Chapter 8: Notes to Financial Statements, including the consideration of costs and benefits. ASU 2018-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted-average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted upon issuance of this update. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this update and delay adoption of the additional disclosures until their effective date. The Company is currently evaluating the provisions of ASU 2018-13 and assessing its impact on the Company's financial statement disclosures. The Company does not believe this standard will have a material impact on the Company's financial statement disclosures.
Fair Value of Financial Instruments	The carrying amounts of financial instruments, including cash, cash equivalents and restricted cash, accounts receivable, accounts payable and accrued expenses, approximate fair value due to the short maturity of these instruments.
Segment Reporting	Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by a company's chief operating decision maker ("CODM"), or a decision-making group, in deciding how to allocate resources and in assessing financial performance. As of September 30, 2019 , the Company's CODM was the Company's CEO. The Company's operating and reportable segments are identified by products and services provided. As of September 30, 2019 , the Company has two reportable segments: (1) Refined Coal ("RC"); and (2) Power Generation and Industrials ("PGI"). The business segment measurements provided to and evaluated by the CODM are computed in accordance with the principles listed below: • The accounting policies of the operating segments are the same as those described in the summary of significant accounting policies in the 2018 Form 10-K. • Segment revenues include equity method earnings and losses from the Company's equity method investments. • Segment operating income (loss) includes segment revenues and allocation of certain "Corporate general and administrative expenses," which include Payroll and benefits , Legal and professional fees and General and administrative . • RC segment operating income includes interest expense directly attributable to the RC segment.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the calculations of basic and diluted earnings per share: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except per share amounts) 2019 2018 2019 2018 Net income $ 3,923 $ 5,503 $ 26,439 $ 28,456 Less: Dividends and undistributed income allocated to participating securities 5 18 37 94 Income attributable to common stockholders $ 3,918 $ 5,485 $ 26,402 $ 28,362 Basic weighted-average common shares outstanding 18,112 19,726 18,184 20,090 Add: dilutive effect of equity instruments 227 150 210 138 Diluted weighted-average shares outstanding 18,339 19,876 18,394 20,228 Earnings per share - basic $ 0.22 $ 0.28 $ 1.45 $ 1.41 Earnings per share - diluted $ 0.21 $ 0.28 $ 1.44 $ 1.40
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	As of the adoption date, the Company recorded $7.0 million and $7.0 million of "right of use" ("ROU") assets and incremental lease liabilities, respectively. The cumulative effect of the change from the adoption of ASC 842 to the Consolidated Balance Sheet as of January 1, 2019 is shown in the table that follows: Balance as of Impact of Balance as of (in thousands) December 31, 2018 Adoption January 1, 2019 Balance Sheet Other long-term assets $ 7,993 $ 6,956 $ 14,949 Other liabilities $ 50,058 $ 3,085 $ 53,143 Other long-term liabilities $ 940 $ 3,871 $ 4,811

Acquisition (Tables)

Acquisition (Tables)	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Summary of Purchase Consideration and Allocation	The following table summarizes the final purchase price allocation. Subsequent to December 31, 2018 , the Company completed additional analysis and adjustments were made to the preliminary purchase price allocations as noted in the table below: Fair value of assets acquired: As Originally Reported Adjustments As Adjusted Cash $ 3,284 $ — $ 3,284 Receivables 6,409 — 6,409 Inventories 22,100 (356 ) 21,744 Prepaid expenses and other current assets 2,992 61 3,053 Spare parts 3,359 — 3,359 Property, plant and equipment 43,033 (377 ) 42,656 Mine leases and development 2,500 200 2,700 Mine reclamation asset — 2,402 2,402 Intangible assets 4,000 100 4,100 Other assets 168 — 168 Amount attributable to assets acquired 87,845 2,030 89,875 Fair value of liabilities assumed: Accounts payable 4,771 — 4,771 Accrued liabilities 7,354 254 7,608 Equipment lease liabilities 8,211 — 8,211 Mine reclamation liability 626 1,776 2,402 Other liabilities 437 — 437 Amount attributable to liabilities assumed 21,399 2,030 23,429 Net assets acquired $ 66,446 $ — $ 66,446
Summary of Finite-Lived Intangible Assets Acquired	The following table represents the intangible assets, as adjusted for purchase price adjustments noted above, identified as part of the Carbon Solutions Acquisition: (in thousands) Amount Weighted Average Useful Life (years) Customer relationships $ 2,200 5 Developed technology 1,600 5 Trade name 300 2 Total intangibles acquired $ 4,100
Business Acquisition, Pro Forma Information	The unaudited pro forma financial information below is not necessarily indicative of either future results of operations or results that might have been achieved had the Carbon Solutions Acquisition been consummated as of January 1, 2017. The following table presents the pro forma effects of the Carbon Solutions Acquisition for the three and nine months ended September 30, 2018 : Three Months Ended Nine Months Ended (in thousands) September 30, 2018 September 30, 2018 Revenues $ 22,447 $ 57,597 Net income $ 8,372 $ 24,434

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory	The following table summarizes the Company's inventories recorded at the lower of average cost or net realizable value as of September 30, 2019 and December 31, 2018 : As of (in thousands) September 30, 2019 December 31, 2018 Product inventory (1) $ 14,953 $ 19,403 Raw material inventory 1,964 2,388 $ 16,917 $ 21,791 (1) As of September 30, 2019 and December 31, 2018, Product inventory includes zero and $5.0 million , respectively, attributed to the increase in fair value of inventory acquired from the Carbon Solutions Acquisition.

Equity Method Investments (Tabl

Equity Method Investments (Tables)	9 Months Ended
	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Equity Method Investments	The following table details the components of the Company's respective equity method investments included within the Earnings from equity method investments line item on the Condensed Consolidated Statements of Operations : Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Earnings from Tinuum Group $ 11,746 $ 8,075 $ 50,757 $ 33,575 Earnings from Tinuum Services 2,682 1,639 6,297 4,281 (Losses) earnings from other (2 ) 1 (3 ) 1 Earnings from equity method investments $ 14,426 $ 9,715 $ 57,051 $ 37,857 The following table details the components of the cash distributions from the Company's respective equity method investments included in the Condensed Consolidated Statements of Cash Flows . Distributions from equity method investees are reported in the Condensed Consolidated Statements of Cash Flows as " Distributions from equity method investees, return on investment " within Operating cash flows until such time as the carrying value in an equity method investee company is reduced to zero; thereafter, such distributions are reported as " Distributions from equity method investees in excess of cumulative earnings " within Investing cash flows. Nine Months Ended September 30, (in thousands) 2019 2018 Distributions from equity method investees, return on investment Tinuum Group $ 50,256 $ — Tinuum Services 6,550 4,000 $ 56,806 $ 4,000 Distributions from equity method investees in excess of investment basis Tinuum Group $ — $ 33,575 $ — $ 33,575 The following tables present the Company's investment balance, equity earnings and cash distributions in excess of the investment balance, if any, for the three and nine months ended September 30, 2019 and 2018 ( in thousands ): Description Date(s) Investment balance ADES equity earnings (loss) Cash distributions Memorandum Account: Cash distributions and equity earnings in (excess) of investment balance Beginning balance 12/31/2018 $ — $ — $ — $ (1,672 ) Impact of adoption of accounting standards (1) First Quarter 37,232 — — — ADES proportionate share of income from Tinuum Group First Quarter 21,439 21,439 — — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) First Quarter (1,672 ) (1,672 ) — 1,672 Cash distributions from Tinuum Group First Quarter (16,788 ) — 16,788 — Total investment balance, equity earnings (loss) and cash distributions 03/31/2019 $ 40,211 $ 19,767 $ 16,788 $ — ADES proportionate share of income from Tinuum Group Second Quarter $ 19,244 $ 19,244 $ — $ — Cash distributions from Tinuum Group Second Quarter (17,000 ) — 17,000 — Total investment balance, equity earnings (loss) and cash distributions 6/30/2019 $ 42,455 $ 19,244 $ 17,000 $ — ADES proportionate share of income from Tinuum Group Third Quarter $ 11,746 $ 11,746 $ — $ — Cash distributions from Tinuum Group Third Quarter (16,468 ) — 16,468 — Total investment balance, equity earnings (loss) and cash distributions 9/30/2019 $ 37,733 $ 11,746 $ 16,468 $ — Description Date(s) Investment balance ADES equity earnings (loss) Cash distributions Memorandum Account: Cash distributions and equity earnings in (excess) of investment balance Beginning balance 12/31/2017 $ — $ — $ — $ (12,218 ) ADES proportionate share of income from Tinuum Group (2) First Quarter 12,458 12,458 — — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) First Quarter (12,218 ) (12,218 ) — 12,218 Cash distributions from Tinuum Group First Quarter (11,050 ) — 11,050 — Adjustment for current year cash distributions in excess of investment balance First Quarter 10,810 10,810 — (10,810 ) Total investment balance, equity earnings (loss) and cash distributions 3/31/2018 $ — $ 11,050 $ 11,050 $ (10,810 ) ADES proportionate share of income from Tinuum Group (2) Second Quarter $ 14,059 $ 14,059 $ — $ — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) Second Quarter (10,810 ) (10,810 ) — 10,810 Cash distributions from Tinuum Group Second Quarter (14,450 ) — 14,450 — Adjustment for current year cash distributions in excess of investment balance Second Quarter 11,201 11,201 — (11,201 ) Total investment balance, equity earnings (loss) and cash distributions 6/30/2018 $ — $ 14,450 $ 14,450 $ (11,201 ) ADES proportionate share of income from Tinuum Group (2) Third Quarter $ 15,798 $ 15,798 $ — $ — Recovery of prior cash distributions in excess of investment balance (prior to cash distributions) Third Quarter (11,201 ) (11,201 ) — 11,201 Cash distributions from Tinuum Group Third Quarter (8,075 ) — 8,075 — Adjustment for current year cash distributions in excess of investment balance Third Quarter 3,478 3,478 — (3,478 ) Total investment balance, equity earnings (loss) and cash distributions 9/30/2018 $ — $ 8,075 $ 8,075 $ (3,478 ) (1) As discussed in Note 1 , Tinuum Group adopted ASC 606 and ASC 842 as of January 1, 2019. As a result of Tinuum Group’s adoption of these standards, the Company recorded a cumulative adjustment of $28.8 million , net of the impact of income taxes, related to the Company's percentage of Tinuum Group's cumulative effect adjustment that increased the Company's Retained earnings as of January 1, 2019. (2) For the three and nine months ended September 30, 2018 , the amount of the Company's 42.5% proportionate share of net income available to members as shown in the table above may differ from mathematical calculations of the Company’s 42.5% equity interest in Tinuum Group multiplied by the amounts of net income available to members as shown in the table above of Tinuum Group's results of operations due to adjustments related to the Class B preferred return. The following table summarizes the results of operations of Tinuum Group: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Gross profit $ 16,810 $ 26,530 $ 96,189 $ 81,626 Operating, selling, general and administrative expenses 11,076 5,908 23,421 17,406 Income from operations 5,734 20,622 72,768 64,220 Other expenses (450 ) (577 ) (427 ) (2,801 ) Class B preferred return — — — (12 ) Loss attributable to noncontrolling interest 22,355 17,126 51,022 38,145 Net income available to members $ 27,639 $ 37,171 $ 123,363 $ 99,552 ADES equity earnings from Tinuum Group $ 11,746 $ 8,075 $ 50,757 $ 33,575 The following table summarizes the results of operations of Tinuum Services: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Gross loss $ (27,834 ) $ (21,362 ) $ (77,761 ) $ (64,069 ) Operating, selling, general and administrative expenses 51,927 43,947 151,789 127,783 Loss from operations (79,761 ) (65,309 ) (229,550 ) (191,852 ) Other (expenses) income (460 ) 78 (1,018 ) 443 Loss attributable to noncontrolling interest 85,586 68,509 243,163 199,971 Net income $ 5,365 $ 3,278 $ 12,595 $ 8,562 ADES equity earnings from Tinuum Services $ 2,682 $ 1,639 $ 6,297 $ 4,281

Debt Obligations (Tables)

Debt Obligations (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Borrowings	As of (in thousands) September 30, 2019 December 31, 2018 Senior Term Loan due December 2021, related party $ 46,000 $ 70,000 Less: net unamortized debt issuance costs (1,380 ) (1,990 ) Less: net unamortized debt discount (1,338 ) (2,052 ) Senior Term Loan due December 2021, net 43,282 65,958 Finance lease obligations (1) 7,066 8,167 50,348 74,125 Less: Current maturities (24,072 ) (24,067 ) Total long-term debt $ 26,276 $ 50,058 (1) As of December 31, 2018, obligations related to capital lease obligations as defined in ASC 840.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Lease, Cost	Lease financial information as of and for the three and nine months ended September 30, 2019 is provided in the following table: (in thousands) Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Finance lease cost: Amortization of right-of-use assets $ 1,277 $ 2,371 Interest on lease liabilities 82 270 Operating lease cost 908 2,764 Short-term lease cost 198 558 Variable lease cost (1) 52 227 Total lease cost $ 2,517 $ 6,190 Other Information: Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 270 Operating cash flows from operating leases $ 2,435 Financing cash flows from finance leases $ 1,016 Right-of-use assets obtained in exchange for new operating lease liabilities $ 1,309 Weighted-average remaining lease term - finance leases 4.4 years Weighted-average remaining lease term - operating leases 2.5 years Weighted-average discount rate - finance leases 6.1 % Weighted-average discount rate - operating leases 8.6 % (1) Primarily includes common area maintenance, property taxes and insurance payable to lessors.
Operating Lease Maturity	The following table summarizes the Company’s future lease payments under finance and operating leases as of September 30, 2019 : (in thousands) Operating Finance Total Lease Commitments 2019 (remaining three months) $ 873 $ 433 $ 1,306 2020 2,718 1,707 4,425 2021 2,035 1,802 3,837 2022 721 951 1,672 2023 359 951 1,310 Thereafter — 2,482 2,482 Total lease payments 6,706 8,326 15,032 Less: Imputed interest (769 ) (1,260 ) (2,029 ) Present value of lease payments $ 5,937 $ 7,066 $ 13,003
Finance Leases Maturity	The following table summarizes the Company’s future lease payments under finance and operating leases as of September 30, 2019 : (in thousands) Operating Finance Total Lease Commitments 2019 (remaining three months) $ 873 $ 433 $ 1,306 2020 2,718 1,707 4,425 2021 2,035 1,802 3,837 2022 721 951 1,672 2023 359 951 1,310 Thereafter — 2,482 2,482 Total lease payments 6,706 8,326 15,032 Less: Imputed interest (769 ) (1,260 ) (2,029 ) Present value of lease payments $ 5,937 $ 7,066 $ 13,003
Future Minimum Rental Payments for Operating Leases	The following table summarizes the Company’s future minimum non-cancellable lease payments due under capital and operating leases as of December 31, 2018: (in thousands) Operating Capital 2019 $ 3,619 $ 1,749 2020 2,273 1,707 2021 1,632 1,802 2022 310 951 2023 221 951 Thereafter — 2,482 Total minimum lease payments $ 8,055 9,642 Less: Imputed interest (1,475 ) Present value of minimum lease payments $ 8,167
Future Minimum Lease Payments for Capital Leases	The following table summarizes the Company’s future minimum non-cancellable lease payments due under capital and operating leases as of December 31, 2018: (in thousands) Operating Capital 2019 $ 3,619 $ 1,749 2020 2,273 1,707 2021 1,632 1,802 2022 310 951 2023 221 951 Thereafter — 2,482 Total minimum lease payments $ 8,055 9,642 Less: Imputed interest (1,475 ) Present value of minimum lease payments $ 8,167

Revenues (Tables)

Revenues (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Accounts Receivable	The following table shows the components of Trade receivables, net: As of (in thousands) September 30, 2019 December 31, 2018 Trade receivables $ 7,338 $ 10,121 Less: Allowance for doubtful accounts (567 ) (567 ) Trade receivables, net $ 6,771 $ 9,554
Schedule of Disaggregation of Revenue	The following tables disaggregate revenues by major component for the three and nine months ended September 30, 2019 and 2018 (in thousands): Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Segment Segment PGI RC Other Total PGI RC Other Total Revenue component Consumables $ 14,010 $ — $ 738 $ 14,748 $ 39,612 $ — $ 1,631 $ 41,243 License royalties, related party — 4,385 — 4,385 — 12,796 — 12,796 Revenues from customers 14,010 4,385 738 19,133 39,612 12,796 1,631 54,039 Earnings from equity method investments — 14,426 — 14,426 — 57,051 — 57,051 Total revenues from customers and earnings from equity method investments $ 14,010 $ 18,811 $ 738 $ 33,559 $ 39,612 $ 69,847 $ 1,631 $ 111,090 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Segment Segment PGI RC Total PGI RC Total Revenue component Consumables $ 1,043 $ — $ 1,043 $ 2,390 $ — $ 2,390 License royalties, related party — 4,104 4,104 — 10,857 10,857 Other — — — 72 — 72 Revenues from customers 1,043 4,104 5,147 2,462 10,857 13,319 Earnings from equity method investments — 9,715 9,715 — 37,857 37,857 Total revenues from customers and earnings from equity method investments $ 1,043 $ 13,819 $ 14,862 $ 2,462 $ 48,714 $ 51,176

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Schedule of Dividends Declared	Dividends per share declared by the Board, and paid quarterly on all outstanding shares of common stock during the three and nine months ended September 30, 2019 and 2018 were as follows: 2019 2018 Per share Date paid Per share Date paid Dividends declared during quarter ended: March 31 $ 0.25 March 7, 2019 $ 0.25 March 8, 2018 June 30 $ 0.25 June 7, 2019 $ 0.25 June 8, 2018 September 30 $ 0.25 September 6, 2019 $ 0.25 September 6, 2018 $ 0.75 $ 0.75

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Allocation of Compensation Expense	Total stock-based compensation expense for the three and nine months ended September 30, 2019 and 2018 was as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 RSA expense $ 468 $ 919 $ 1,326 $ 1,871 Stock option expense — — — 58 Total stock-based compensation expense $ 468 $ 919 $ 1,326 $ 1,929
Schedule of Unrecognized Compensation Cost	The amount of unrecognized compensation cost as of September 30, 2019 , and the expected weighted-average period over which the cost will be recognized is as follows: As of September 30, 2019 (in thousands) Unrecognized Compensation Cost Expected Weighted- RSA expense $ 3,146 1.67 Total unrecognized stock-based compensation expense $ 3,146 1.67
Summary of Restricted Stock Activity	A summary of RSA and RSU activity under the Company's various stock compensation plans for the nine months ended September 30, 2019 is presented below: Restricted Stock Weighted-Average Grant Date Fair Value (in thousands, except for share and per share amounts) Awards Units RSA's RSU's Non-vested at January 1, 2019 280,852 20,000 $ 9.92 $ 10.52 Granted 275,983 — $ 11.07 $ — Vested (84,156 ) — $ 9.74 $ — Forfeited (3,498 ) — $ 10.96 $ — Non-vested at September 30, 2019 469,181 20,000 $ 10.62 $ 10.52
Summary of Option Activity	A summary of stock option activity for the nine months ended September 30, 2019 is presented below: Number of Options Weighted-Average Aggregate Intrinsic Value (in thousands) Weighted-Average Options outstanding, January 1, 2019 529,780 $ 12.23 Options granted — — Options exercised (185,332 ) 9.50 Options expired / forfeited (20,000 ) 20.07 Options outstanding, September 30, 2019 324,448 $ 13.31 $ 497 0.74 Options exercisable, September 30, 2019 324,448 $ 13.31 $ 497 0.74

Supplemental Financial Inform_2

Supplemental Financial Information (Tables)	9 Months Ended
	Sep. 30, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Prepaid Expenses and Other Assets and Other assets	The following table summarizes the components of Prepaid expenses and other assets and Other long-term assets, net as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Prepaid expenses and other assets: Prepaid expenses $ 1,635 $ 1,233 Prepaid income taxes 2,753 2,940 Other 1,682 1,397 $ 6,070 $ 5,570 Other long-term assets, net: Highview Investment $ 552 $ 552 Spare parts 3,325 3,278 Mine development costs, net 4,672 2,531 Mine reclamation asset, net 2,291 — Prepaid royalty expense, long-term 955 955 Right of use assets, operating leases, net 5,894 — Other long-term assets 674 677 $ 18,363 $ 7,993
Schedule of Other Liabilities	The following table details the components of Other current liabilities and Other long-term liabilities as presented in the Condensed Consolidated Balance Sheets: As of (in thousands) September 30, December 31, Other current liabilities: Current portion of operating lease obligations $ 2,605 $ — Accrued interest 339 407 Income and other taxes payable 420 479 Other 923 1,252 $ 4,287 $ 2,138 Other long-term liabilities: Operating lease obligations, long-term $ 3,332 $ — Mine reclamation liability 2,540 624 Other long-term liabilities 190 316 $ 6,062 $ 940
Schedule of Statement of Operations, Supplemental Disclosures	The following table details the components of Interest expense in the Condensed Consolidated Statements of Operations: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Interest on Senior Term Loan $ 940 $ — $ 3,344 $ — Debt discount and debt issuance costs 473 — 1,324 — 453A interest 234 388 882 1,128 Other 82 11 270 19 $ 1,729 $ 399 $ 5,820 $ 1,147

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense and Effective Tax Rates	For the three and nine months ended September 30, 2019 and 2018 , the Company's income tax expense and effective tax rates based on forecasted pre-tax income were: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except for rate) 2019 2018 2019 2018 Income tax expense $ 6,595 $ 3,931 $ 14,928 $ 5,151 Effective tax rate 63 % 42 % 36 % 15 %

Business Segment Information (T

Business Segment Information (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Operating Results	The following table presents the Company's operating segment results for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Revenues: Refined Coal: Earnings in equity method investments $ 14,426 $ 9,715 $ 57,051 $ 37,857 License royalties, related party 4,385 4,104 12,796 10,857 18,811 13,819 69,847 48,714 Power Generation and Industrials: Consumables 14,010 1,043 39,612 2,390 Other — — — 72 14,010 1,043 39,612 2,462 Total segment reporting revenues 32,821 14,862 109,459 51,176 Adjustments to reconcile to reported revenues: Earnings in equity method investments (14,426 ) (9,715 ) (57,051 ) (37,857 ) Corporate and other 738 — 1,631 — Total reported revenues $ 19,133 $ 5,147 $ 54,039 $ 13,319 Segment operating income (loss): Refined Coal (1) $ 18,158 $ 12,798 $ 68,137 $ 45,775 Power Generation and Industrials (2) (977 ) (1,168 ) (8,301 ) (3,493 ) Total segment operating income $ 17,181 $ 11,630 $ 59,836 $ 42,282 (1) Included in RC segment operating income for the three and nine months ended September 30, 2019 and 2018 is 453A interest expense of $0.2 million and $0.9 million and $0.4 million and $1.1 million , respectively. (2) Included in PGI segment operating loss for the nine months ended September 30, 2019 was $4.7 million of costs recognized as a result of the step-up in inventory fair value recorded from the Carbon Solutions Acquisition. Also included in PGI segment operating loss for the three and nine months ended September 30, 2019 was $1.9 million and $4.5 million , respectively, of depreciation, amortization, and depletion expense on mine and plant long-lived assets.
Reconciliation of Reportable Segment Amounts to Consolidated Balances	A reconciliation of reportable segment operating income to the Company's consolidated income before income tax expense is as follows: Three Months Ended September 30, Nine Months Ended September 30, (in thousands) 2019 2018 2019 2018 Total reported segment operating income $ 17,181 $ 11,630 $ 59,836 $ 42,282 Other operating loss (658 ) — (1,409 ) — 16,523 11,630 58,427 42,282 Adjustments to reconcile to income before income tax expense attributable to the Company: Corporate payroll and benefits (768 ) (957 ) (2,004 ) (3,054 ) Corporate legal and professional fees (1,737 ) (634 ) (5,254 ) (3,222 ) Corporate general and administrative (2,278 ) (658 ) (5,427 ) (2,483 ) Corporate depreciation and amortization (21 ) (23 ) (41 ) (97 ) Corporate interest (expense) income, net (1,413 ) (10 ) (4,668 ) (18 ) Other income (expense), net 212 86 334 199 Income before income tax expense $ 10,518 $ 9,434 $ 41,367 $ 33,607
Reconciliation of Assets from Segment to Consolidated	A reconciliation of reportable segment assets to the Company's consolidated assets is as follows: As of (in thousands) September 30, December 31, Assets: Refined Coal (1) $ 49,055 $ 11,468 Power Generation and Industrials 82,121 85,786 Total segment assets 131,176 97,254 All Other and Corporate (2) 47,552 62,410 Consolidated $ 178,728 $ 159,664 (1) Includes $44.1 million and $6.6 million of investments in equity method investees, respectively. (2) Includes the Company's deferred tax assets.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Estimated Fair Values of Remaining Financial Instruments	The following table provides the estimated fair values of the remaining financial instruments: As of September 30, 2019 As of December 31, 2018 (in thousands) Carrying Value Fair Value Carrying Value Fair Value Financial Instruments: Highview Investment $ 552 $ 552 $ 552 $ 552 Highview Obligation $ 207 $ 207 $ 213 $ 213

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	A summary of the net pretax charges, incurred by segment, for the three and nine months ended September 30, 2018 is as follows: Pretax Charge (in thousands, except employee data) Approximate Number of Employees Refined Coal (1) Power Generation and Industrials (1) All Other and Corporate (1) Total Three Months Ended September 30, 2018 Restructuring charges 7 $ 168 $ 500 $ 434 $ 1,102 Changes in estimates — — — — Total pretax charge, net of reversals $ 168 $ 500 $ 434 $ 1,102 Nine Months Ended September 30, 2018 Restructuring charges 13 $ 448 $ 996 $ 557 $ 2,001 Changes in estimates — — — — Total pretax charge, net of reversals $ 448 $ 996 $ 557 $ 2,001 (1) Restructuring charges were allocated consistent with the allocations made in Note 13 - Business Segment Information
Schedule of Restructuring Reserve by Type of Cost	The following table summarizes the Company's change in restructuring accruals for the nine months ended September 30, 2019 : (in thousands) Employee Severance Remaining accrual as of December 31, 2018 $ 2,208 Expense provision 233 Cash payments and other (1,758 ) Change in estimates (104 ) Remaining accrual as of September 30, 2019 $ 579

Basis of Presentation - Nature

Basis of Presentation - Nature of Operations and Risks (Details) - debt_instrument	Sep. 30, 2019	Dec. 07, 2018
Tinuum Group, LLC
Concentration Risk [Line Items]
Number of instruments held	23
Tinuum Group, LLC | Customer Concentration Risk
Concentration Risk [Line Items]
Number of instruments held	11
ADA Carbon Solutions, LLC
Concentration Risk [Line Items]
Ownership interest		100.00%

Basis of Presentation - Calcula

Basis of Presentation - Calculations of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Accounting Policies [Abstract]
Net income	$ 3,923	$ 8,114	$ 14,402	$ 5,503	$ 15,291	$ 7,662	$ 26,439	$ 28,456
Less: Dividends and undistributed income allocated to participating securities	5			18			37	94
Income attributable to common stockholders	$ 3,918			$ 5,485			$ 26,402	$ 28,362
Basic weighted-average common shares outstanding (in shares)	18,112			19,726			18,184	20,090
Add: dilutive effect of equity instruments (in shares)	227			150			210	138
Diluted weighted-average shares outstanding (in shares)	18,339			19,876			18,394	20,228
Earnings per share - basic (in dollars per share)	$ 0.22			$ 0.28			$ 1.45	$ 1.41
Earnings per share - diluted (in dollars per share)	$ 0.21			$ 0.28			$ 1.44	$ 1.40
Restricted Sock and Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares excluded from diluted shares outstanding (in shares)	300			300			300	300
Performance share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares excluded from diluted shares outstanding (in shares)								100

Basis of Presentation - Adjustm

Basis of Presentation - Adjustments for Adoption (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Aug. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right of use asset	$ 5,894	$ 1,200		$ 0
Operating lease, liability	5,937	$ 1,200
Other long-term assets	18,363		$ 14,949	7,993
Other liabilities			53,143	50,058
Other long-term liabilities	$ 6,062		4,811	$ 940
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right of use asset			7,000
Operating lease, liability			7,000
Other long-term assets			6,956
Other liabilities			3,085
Other long-term liabilities			$ 3,871

Basis of Presentation - Recentl

Basis of Presentation - Recently Adopted (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 54,237		$ 12,914
Tinuum Group, LLC
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investments		$ 37,200
Deferred tax liabilities		8,400
Difference between Revenue Guidance in Effect before and after Topic 606 | ASU No. 2014-09 | Tinuum Group, LLC
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ 28,800

Acquisition - Additional Inform

Acquisition - Additional Information (Details) - USD ($) $ in Thousands	Dec. 07, 2018	Jan. 01, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Revenues			$ (19,133)	$ (5,147)
Power Generation and Industrials | ASU No. 2014-09 | Calculated under Revenue Guidance in Effect before Topic 606
Business Acquisition [Line Items]
Revenues		$ 2,100
Cost of revenue		$ 5,900
ADA Carbon Solutions, LLC
Business Acquisition [Line Items]
Purchase price	$ 75,000
Consideration transferred	66,500
Cash paid	65,800
Purchase adjustments payable	700
Assumed debt and contractual commitments	11,800
Cash acquired	3,300
Acquisition related costs						$ 4,500
Removal of transaction costs			$ 1,000		$ 4,200
ADA Carbon Solutions, LLC | Senior Term Loan due December 2021, net | Term Loan
Business Acquisition [Line Items]
Proceeds from issuance of debt	$ 70,000

Acquisition - Allocation (Detai

Acquisition - Allocation (Details) - ADA Carbon Solutions, LLC - USD ($) $ in Thousands	3 Months Ended	10 Months Ended
	Jun. 30, 2019	Sep. 30, 2019	Dec. 07, 2018
Fair value of assets acquired:
Cash		$ 3,284	$ 3,284
Receivables		6,409	6,409
Inventories		21,744	22,100
Prepaid expenses and other current assets		3,053	2,992
Spare parts		3,359	3,359
Property, plant and equipment		42,656	43,033
Mine leases and development		2,700	2,500
Mine reclamation asset		2,402	0
Intangible assets	$ 4,100	4,100	4,000
Other assets		168	168
Amount attributable to assets acquired		89,875	87,845
Fair value of liabilities assumed:
Accounts payable		4,771	4,771
Accrued liabilities		7,608	7,354
Equipment lease liabilities		8,211	8,211
Mine reclamation liability		2,402	626
Other liabilities		437	437
Amount attributable to liabilities assumed		23,429	21,399
Adjustments
Cash		0
Receivables		0
Inventories		(356)
Prepaid expenses and other current assets		61
Spare parts		0
Property, plant and equipment		(377)
Mine leases and development		200
Mine reclamation asset		2,402
Intangible assets		100
Other assets		0
Amount attributable to assets acquired		2,030
Accounts payable		0
Accrued liabilities		254
Equipment lease liabilities		0
Mine reclamation liability		1,776
Other liabilities		0
Amount attributable to liabilities assumed		2,030
Net assets acquired		66,446	$ 66,446
Net assets acquired		$ 0
Customer relationships
Fair value of assets acquired:
Intangible assets	$ 2,200
Adjustments
Weighted Average Useful Life (years)	5 years
Developed technology
Fair value of assets acquired:
Intangible assets	$ 1,600
Adjustments
Weighted Average Useful Life (years)	5 years
Trade name
Fair value of assets acquired:
Intangible assets	$ 300
Adjustments
Weighted Average Useful Life (years)	2 years

Acquisition - Pro Forma (Detail

Acquisition - Pro Forma (Details) - ADA Carbon Solutions, LLC - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Business Acquisition [Line Items]
Revenues	$ 22,447	$ 57,597
Net income	$ 8,372	$ 24,434

Inventories (Details)

Inventories (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Product inventory	$ 14,953,000	$ 19,403,000
Raw material inventory	1,964,000	2,388,000
Inventories	16,917,000	21,791,000
Inventory acquired	$ 0	$ 5,000,000

Equity Method Investments - Nar

Equity Method Investments - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 44,111,000		$ 44,111,000				$ 6,634,000
Earnings from equity method investments	$ 14,426,000	$ 9,715,000	$ 57,051,000	$ 37,857,000
Tinuum Group, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest, percent	42.50%	42.50%	42.50%	42.50%			42.50%
Equity method investments	$ 37,733,000	$ 0	$ 37,733,000	$ 0	$ 42,455,000	$ 40,211,000	$ 0	$ 0	$ 0	$ 0
Earnings from equity method investments	$ 11,746,000	8,075,000	$ 50,757,000	33,575,000
Tinuum Services, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest, percent	50.00%		50.00%
Equity method investments	$ 6,300,000		$ 6,300,000				$ 6,600,000
Earnings from equity method investments	$ 2,682,000	$ 1,639,000	$ 6,297,000	$ 4,281,000
Percent of losses removed from net income, attributable to noncontrolling interest	100.00%		100.00%

Equity Method Investments - Res

Equity Method Investments - Results of Operations and Summary of Distributions (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
ADES equity earnings	$ 14,426			$ 9,715			$ 57,051	$ 37,857
Equity Method Investment, Financial Statement, Reported Amounts [Abstract]
Distributions from equity method investees, return on investment							56,806	4,000
Included in investing cash flows							0	33,575
Tinuum Group, LLC
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Gross profit (loss)	16,810			26,530			96,189	81,626
Operating, selling, general and administrative expenses	11,076			5,908			23,421	17,406
Income (loss) from operations	5,734			20,622			72,768	64,220
Other expenses	(450)			(577)			(427)	(2,801)
Class B preferred return	0			0			0	(12)
Loss attributable to noncontrolling interest	22,355			17,126			51,022	38,145
Net income available to members	27,639			37,171			123,363	99,552
ADES equity earnings	11,746			8,075			50,757	33,575
Equity Method Investment, Financial Statement, Reported Amounts [Abstract]
Distributions from equity method investees, return on investment							50,256	0
Distributions from equity method investees in excess of investment basis							0	33,575
Included in investing cash flows	16,468	$ 17,000	$ 16,788	8,075	$ 14,450	$ 11,050
Tinuum Services, LLC
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Gross profit (loss)	(27,834)			(21,362)			(77,761)	(64,069)
Operating, selling, general and administrative expenses	51,927			43,947			151,789	127,783
Income (loss) from operations	(79,761)			(65,309)			(229,550)	(191,852)
Other expenses	(460)			78			(1,018)	443
Loss attributable to noncontrolling interest	85,586			68,509			243,163	199,971
Net income available to members	5,365			3,278			12,595	8,562
ADES equity earnings	2,682			1,639			6,297	4,281
Equity Method Investment, Financial Statement, Reported Amounts [Abstract]
Distributions from equity method investees, return on investment							6,550	4,000
(Losses) earnings from other
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
ADES equity earnings	$ (2)			$ 1			$ (3)	$ 1

Equity Method Investments - Rol

Equity Method Investments - Rollforward of CCS Investment (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Equity Method Investments [Roll Forward]
Beginning balance			$ 6,634,000				$ 6,634,000
Cash distributions from Tinuum Group							0	$ 33,575,000
Total investment balance, equity earnings (loss) and cash distributions	$ 44,111,000						44,111,000
Retained earnings	54,237,000						54,237,000			$ 12,914,000
Tinuum Group, LLC
Equity Method Investments [Roll Forward]
Beginning balance	42,455,000	$ 40,211,000	0	$ 0	$ 0	$ 0	0	0
Impact of adoption of accounting standards									$ 37,232,000
ADES proportionate share of income from Tinuum Group	11,746,000	19,244,000	21,439,000	15,798,000	14,059,000	12,458,000
Recovery of prior cash distributions in excess of investment balance (prior to cash distributions)			1,672,000	11,201,000	10,810,000	12,218,000
Cash distributions from Tinuum Group	16,468,000	17,000,000	16,788,000	8,075,000	14,450,000	11,050,000
Adjustment for current year cash distributions in excess of investment balance				3,478,000	11,201,000	10,810,000
Total investment balance, equity earnings (loss) and cash distributions	$ 37,733,000	42,455,000	40,211,000	$ 0	0	0	$ 37,733,000	$ 0
Ownership interest, percent	42.50%			42.50%			42.50%	42.50%		42.50%
Ownership interest multiplied by net income available to members, percent				42.50%				42.50%
Tinuum Group, LLC | Difference between Revenue Guidance in Effect before and after Topic 606 | ASU No. 2014-09
Equity Method Investments [Roll Forward]
Retained earnings									28,800,000
Tinuum Group, LLC | ADES equity earnings (loss)
Equity Method Investments [Roll Forward]
Beginning balance	$ 19,244,000	19,767,000	0	$ 14,450,000	11,050,000	0	$ 0	$ 0
Impact of adoption of accounting standards									0
ADES proportionate share of income from Tinuum Group	11,746,000	19,244,000	21,439,000	15,798,000	14,059,000	12,458,000
Recovery of prior cash distributions in excess of investment balance (prior to cash distributions)			1,672,000	11,201,000	10,810,000	12,218,000
Cash distributions from Tinuum Group	0		0	0	0	0
Adjustment for current year cash distributions in excess of investment balance		0		3,478,000	11,201,000	10,810,000
Total investment balance, equity earnings (loss) and cash distributions	11,746,000	19,244,000	19,767,000	8,075,000	14,450,000	11,050,000	11,746,000	8,075,000
Tinuum Group, LLC | Cash distributions
Equity Method Investments [Roll Forward]
Beginning balance	17,000,000	16,788,000	0	14,450,000	11,050,000	0	0	0
Impact of adoption of accounting standards									0
ADES proportionate share of income from Tinuum Group	0	0	0	0	0	0
Recovery of prior cash distributions in excess of investment balance (prior to cash distributions)			0	0	0	0
Cash distributions from Tinuum Group	16,468,000	17,000,000	16,788,000	8,075,000	14,450,000	11,050,000
Adjustment for current year cash distributions in excess of investment balance				0	0	0
Total investment balance, equity earnings (loss) and cash distributions	16,468,000	17,000,000	16,788,000	8,075,000	14,450,000	11,050,000	16,468,000	8,075,000
Tinuum Group, LLC | Memorandum Account: Cash distributions and equity loss in (excess) of investment balance
Equity Method Investments [Roll Forward]
Beginning balance	0	0	1,672,000	11,201,000	10,810,000	12,218,000	1,672,000	12,218,000
Impact of adoption of accounting standards									$ 0
ADES proportionate share of income from Tinuum Group	0	0	0	0	0	0
Recovery of prior cash distributions in excess of investment balance (prior to cash distributions)			1,672,000	11,201,000	10,810,000	12,218,000
Cash distributions from Tinuum Group	0		0	0	0	0
Adjustment for current year cash distributions in excess of investment balance		0		3,478,000	11,201,000	10,810,000
Total investment balance, equity earnings (loss) and cash distributions	$ 0	$ 0	$ 0	$ 3,478,000	$ 11,201,000	$ 10,810,000	$ 0	$ 3,478,000

Debt Obligations - Schedule of

Debt Obligations - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 07, 2018
Debt Instrument [Line Items]
Finance lease obligations	$ 7,066
Finance lease obligations		$ 8,167
Long-term Debt	50,348	74,125
Less: Current maturities	(24,072)	(24,067)
Total long-term debt	26,276	50,058
Senior Term Loan due December 2021, net
Debt Instrument [Line Items]
Less: net unamortized debt issuance costs	(1,380)	(1,990)	$ (2,000)
Less: net unamortized debt discount	(1,338)	(2,052)	$ (2,100)
Senior Term Loan due December 2021, net	43,282	65,958
Senior Term Loan due December 2021, net | Senior Term Loan due December 2021, related party
Debt Instrument [Line Items]
Senior Term Loan due December 2021, related party	$ 46,000	$ 70,000

Debt Obligations - Senior Term

Debt Obligations - Senior Term Loan (Details)	Dec. 07, 2018USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2018USD ($)
Senior Term Loan
Debt Instrument [Line Items]
Less: net unamortized debt discount	$ 2,100,000	$ 1,338,000	$ 2,052,000
Debt issuance costs	$ 2,000,000	1,380,000	$ 1,990,000
Term	36 months
Interest rate, stated percentage	4.75%
Minimum cash balance required		$ 5,000,000
Expected future net cash flows from refined coal business		1.75
Maximum annual collective dividends and buybacks		$ 30,000,000
Minimum requirement from future net cash flows from refined coal business		$ 100,000,000
Senior Term Loan | Beginning on March 1, 2019
Debt Instrument [Line Items]
Periodic payment, principal	$ 6,000,000
Senior Term Loan | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%
ADA Carbon Solutions, LLC | Term Loan | Senior Term Loan
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 70,000,000
Senior Term Loan due December 2021, related party | Minimum
Debt Instrument [Line Items]
Percent of common stock owned	5.00%

Debt Obligations - Line of Cred

Debt Obligations - Line of Credit (Details) - USD ($)	Sep. 30, 2019	Dec. 07, 2018	Sep. 30, 2018
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 5,000,000
Line of credit	$ 0
Line of Credit
Debt Instrument [Line Items]
Minimum cash balance required		$ 5,000,000
Senior Term Loan
Debt Instrument [Line Items]
Face amount		$ 70,000,000
Minimum cash balance required	$ 5,000,000
Maximum
Debt Instrument [Line Items]
Line of credit facility, used as collateral			5,000,000
Minimum
Debt Instrument [Line Items]
Requirements for EBITDA			$ 24,000,000

Leases - Narrative (Details)

Leases - Narrative (Details) ft² in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2019USD ($)ft²	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Lessee, Lease, Description [Line Items]
Long-term lease liabilities		$ 7,066,000		$ 7,066,000
Finance lease, right of use asset		6,400,000		6,400,000
Operating lease, right of use asset	$ 1,200,000	5,894,000		5,894,000		$ 0
Operating lease, expense		1,100,000		3,300,000
Amortization of right-of-use assets		1,277,000		2,371,000
Square feet under lease | ft²	21
Operating leases, term of contract	3 years 6 months
Operating lease, liability	$ 1,200,000	5,937,000		5,937,000
Capital leased assets						8,100,000
Capital lease obligations						8,167,000
Accrued lease payments and accrued lease incentives						100,000
Property and equipment		44,168,000		44,168,000		42,697,000
Accumulated depreciation and amortization		5,651,000		5,651,000		1,499,000
Assets Held under Capital Leases
Lessee, Lease, Description [Line Items]
Property and equipment						8,100,000
Accumulated depreciation and amortization						$ 100,000
General and Administrative Expense
Lessee, Lease, Description [Line Items]
Amortization of right-of-use assets		104,000		300,000
Rent expense			$ 100,000		$ 200,000
Consumables
Lessee, Lease, Description [Line Items]
Operating lease, expense		$ 1,000,000		$ 3,100,000

Leases - Lease Liabilities (Det

Leases - Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Lease, cost
Amortization of right-of-use assets	$ 1,277	$ 2,371
Interest on lease liabilities	82	270
Operating lease cost	908	2,764
Short-term lease cost	198	558
Variable lease cost	52	227
Total lease cost	$ 2,517	6,190
Operating cash flows from finance leases		270
Operating cash flows from operating leases		2,435
Financing cash flows from finance leases		1,016	$ 0
Right-of-use assets obtained in exchange for new operating lease liabilities		$ 1,309
Weighted-average remaining lease term - finance leases	4 years 5 months 6 days	4 years 5 months 6 days
Weighted-average remaining lease term - operating leases	2 years 6 months	2 years 6 months
Weighted-average discount rate - finance leases	6.10%	6.10%
Weighted-average discount rate - operating leases	8.60%	8.60%

Leases - Disclosures under ASC

Leases - Disclosures under ASC 840 (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Aug. 31, 2019	Dec. 31, 2018
Operating Leases ASC 842
2019 (remaining three months)	$ 873
2020	2,718
2021	2,035
2022	721
2023	359
Thereafter	0
Total minimum lease payments	6,706
Less: Imputed interest	(769)
Present value of minimum lease payments	5,937	$ 1,200
Finance Leases ASC 842
2019 (remaining three months)	433
2020	1,707
2021	1,802
2022	951
2023	951
Thereafter	2,482
Total minimum lease payments	8,326
Less: Imputed interest	(1,260)
Present value of minimum lease payments	7,066
Leases ASC 842
2019 (remaining three months)	1,306
2020	4,425
2021	3,837
2022	1,672
2023	1,310
Thereafter	2,482
Total lease payments	15,032
Less: Imputed interest	(2,029)
Present value of lease payments	$ 13,003
Operating Leases, Future Minimum Payments
2019			$ 3,619
2020			2,273
2021			1,632
2022			310
2023			221
Thereafter			0
Total minimum lease payments			8,055
Capital Leases, Future Minimum Payments
2019			1,749
2020			1,707
2021			1,802
2022			951
2023			951
Thereafter			2,482
Total minimum lease payments			9,642
Less: Imputed interest			(1,475)
Present value of minimum lease payments			$ 8,167

Revenues - Narrative (Details)

Revenues - Narrative (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)segment
Revenue from Contract with Customer [Abstract]
Collection terms		Credit terms are generally net 30 from the date of invoice.
Provision for debt expense | $	$ 0	$ 0
Number of operating segments | segment		2

Revenues - Trade Receivables (D

Revenues - Trade Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Trade receivables	$ 7,338	$ 10,121
Less: Allowance for doubtful accounts	(567)	(567)
Total	$ 6,771	$ 9,554

Revenues - Disaggregation of Re

Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue component	$ 19,133	$ 5,147	$ 54,039	$ 13,319
Earnings from equity method investments	14,426	9,715	57,051	37,857
Total revenues from customers and earnings from equity method investments	19,133	5,147
Total revenues from customers and earnings from equity method investments	33,559		111,090
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues from customers and earnings from equity method investments	32,821	14,862	109,459	51,176
Consumables
Disaggregation of Revenue [Line Items]
Revenue component	14,748	1,043	41,243	2,390
License royalties, related party
Disaggregation of Revenue [Line Items]
Revenue component	4,385	4,104	12,796	10,857
Other
Disaggregation of Revenue [Line Items]
Revenue component	0	0	0	72
Power Generation and Industrials
Disaggregation of Revenue [Line Items]
Revenue component	14,010	1,043	39,612	2,462
Earnings from equity method investments	0	0	0	0
Power Generation and Industrials | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues from customers and earnings from equity method investments	14,010	1,043	39,612	2,462
Power Generation and Industrials | Consumables
Disaggregation of Revenue [Line Items]
Revenue component	14,010	1,043	39,612	2,390
Power Generation and Industrials | Consumables | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue component	14,010	1,043	39,612	2,390
Power Generation and Industrials | License royalties, related party
Disaggregation of Revenue [Line Items]
Revenue component	0	0	0	0
Power Generation and Industrials | Other
Disaggregation of Revenue [Line Items]
Revenue component		0		72
Power Generation and Industrials | Other | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue component	0	0	0	72
Refined Coal
Disaggregation of Revenue [Line Items]
Revenue component	4,385	4,104	12,796	10,857
Earnings from equity method investments	14,426	9,715	57,051	37,857
Refined Coal | Operating Segments
Disaggregation of Revenue [Line Items]
Earnings from equity method investments	14,426	9,715	57,051	37,857
Total revenues from customers and earnings from equity method investments	18,811	13,819	69,847	48,714
Refined Coal | Consumables
Disaggregation of Revenue [Line Items]
Revenue component	0	0	0	0
Refined Coal | License royalties, related party
Disaggregation of Revenue [Line Items]
Revenue component	4,385	4,104	12,796	10,857
Refined Coal | Other
Disaggregation of Revenue [Line Items]
Revenue component		$ 0		$ 0
Other
Disaggregation of Revenue [Line Items]
Revenue component	738		1,631
Earnings from equity method investments	0		0
Other | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues from customers and earnings from equity method investments	738		1,631
Other | Consumables
Disaggregation of Revenue [Line Items]
Revenue component	738		1,631
Other | License royalties, related party
Disaggregation of Revenue [Line Items]
Revenue component	$ 0		$ 0

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Restricted cash, long-term	$ 5,000,000	$ 5,195,000
Restricted cash, short term	$ 0	$ 100,000
Tinuum Group, LLC
Related Party Transaction [Line Items]
Limited guarantees. percent	50.00%

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Nov. 30, 2018	May 05, 2017
Class of Stock [Line Items]
Stock repurchased	$ 116,000	$ 9,000	$ 245,000	$ 348,000	$ 92,000	$ 267,000
Maximum
Class of Stock [Line Items]
Requirement to own shares outstanding as percent										4.99%
Common Stock
Class of Stock [Line Items]
Stock repurchased (in shares)	8,152			186,212			256,743	1,011,630
Stock repurchased	$ 100,000			$ 2,100,000			$ 2,900,000	$ 11,200,000
Common Stock | Single Block through a Privately Negotiated Transaction
Class of Stock [Line Items]
Stock repurchased				$ 2,100,000				$ 4,300,000
Common Stock | Maximum
Class of Stock [Line Items]
Authorized amount									$ 20,000,000

Stockholders' Equity - Dividend

Stockholders' Equity - Dividends (Details) - $ / shares	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity [Abstract]
Dividends declared (in dollars per share)	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.75	$ 0.75

Stock-Based Compensation - Allo

Stock-Based Compensation - Allocation of Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 468	$ 919	$ 1,326	$ 1,929
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	468	919	1,326	1,871
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 0	$ 0	$ 0	$ 58

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Unrecognized Compensation Cost (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 3,146
Expected Weighted- Average Period of Recognition (in years)	1 year 8 months 1 day
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 3,146
Expected Weighted- Average Period of Recognition (in years)	1 year 8 months 1 day

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock options exercised	$ 0
Intrinsic value of options exercised	$ 400,000
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Expected term (in years)		5 years
Shares withheld as payment of exercise price	149,715

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Non-vested Restricted Stock Activity (Details)	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Restricted stock awards
Number of SAR's Outstanding and Exercisable
Non-vested shares, Beginning balance (in shares) | shares	280,852
Granted (in shares) | shares	275,983
Vested (in shares) | shares	(84,156)
Forfeited (in shares) | shares	(3,498)
Non-vested shares, Ending balance (in shares) | shares	469,181
Units
Non-vested shares, Weighted-Average Grant Date Fair Value, Beginning Balance (in dollars per share) | $ / shares	$ 9.92
Granted, Weighted-Average Grant Date Fair Value (in dollars per share) | $ / shares	11.07
Vested in period, Weighted-Average Grant Date Fair Value (in dollars per share) | $ / shares	9.74
Forfeited, Weighted-Average Grant Date Fair Value (in dollars per share) | $ / shares	10.96
Non-vested shares, Weighted-Average Grant Date Fair Value, Ending Balance (in dollars per share) | $ / shares	$ 10.62
RSUs
Number of SAR's Outstanding and Exercisable
Non-vested shares, Beginning balance (in shares) | shares	20,000
Granted (in shares) | shares	0
Vested (in shares) | shares	0
Forfeited (in shares) | shares	0
Non-vested shares, Ending balance (in shares) | shares	20,000
Units
Non-vested shares, Weighted-Average Grant Date Fair Value, Beginning Balance (in dollars per share) | $ / shares	$ 10.52
Granted, Weighted-Average Grant Date Fair Value (in dollars per share) | $ / shares	0
Vested in period, Weighted-Average Grant Date Fair Value (in dollars per share) | $ / shares	0
Forfeited, Weighted-Average Grant Date Fair Value (in dollars per share) | $ / shares	0
Non-vested shares, Weighted-Average Grant Date Fair Value, Ending Balance (in dollars per share) | $ / shares	$ 10.52

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Option Activity (Details) - Stock options - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2019
Employee and Director Options
Options outstanding, start of year (in shares)	529,780
Options granted (in shares)	0
Options exercised (in shares)	(185,332)
Options expired / forfeited (in shares)	(20,000)
Options outstanding, end of year (in shares)	324,448
Options vested and exercisable (in shares)	324,448
Weighted Average Exercise Price
Options outstanding, start of year (in dollars per share)	$ 12.23
Options granted (in dollars per share)	0
Options exercised (in dollars per share)	9.50
Options expired / forfeited (in dollars per share)	20.07
Options outstanding, end of year (in dollars per share)	13.31
Options vested and exercisable, weighted average exercise price (in dollars per share)	$ 13.31
Options outstanding, intrinsic value	$ 497
Options exercisable, intrinsic value	$ 497
Options outstanding, weighted average remaining contractual term	8 months 26 days
Options exercisable, weighted average remaining contractual term	8 months 26 days

Supplemental Financial Inform_3

Supplemental Financial Information - Prepaid expenses and other assets and Other assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Aug. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Prepaid expenses and other assets:
Prepaid expenses	$ 1,635			$ 1,233
Prepaid income taxes	2,753			2,940
Other	1,682			1,397
Other current assets	6,070			5,570
Other long-term assets, net:
Highview Investment	552			552
Spare parts	3,325			3,278
Mine development costs, net	4,672			2,531
Mine reclamation asset, net	2,291			0
Prepaid royalty expense, long-term	955			955
Right of use assets, operating leases, net	5,894	$ 1,200		0
Other long-term assets	674			677
Total	$ 18,363		$ 14,949	$ 7,993

Supplemental Financial Inform_4

Supplemental Financial Information - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Nov. 30, 2014	Sep. 30, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Mine reserves, amortization period		18 years
Mine
Investment [Line Items]
Useful life		18 years
Highview Enterprises Limited
Investment [Line Items]
Ownership interest, percent	8.00%
Payments to acquire investments	$ 2.8

Supplemental Financial Inform_5

Supplemental Financial Information - Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Other current liabilities:
Current portion of operating lease obligations	$ 2,605		$ 0
Accrued interest	339		407
Income and other taxes payable	420		479
Other	923		1,252
Other current liabilities	4,287		2,138
Other long-term liabilities:
Operating lease obligations, long-term	3,332		0
Mine reclamation liability	2,540		624
Other long-term liabilities	190		316
Other long-term liabilities	$ 6,062	$ 4,811	$ 940

Supplemental Financial Inform_6

Supplemental Financial Information - Supplemental Income Statement, Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Interest on Senior Term Loan	$ 940	$ 0	$ 3,344	$ 0
Debt discount and debt issuance costs	473	0	1,324	0
453A interest	234	388	882	1,128
Other	82	11	270	19
Interest expense	$ 1,729	$ 399	$ 5,820	$ 1,147

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income tax expense	$ 6,595	$ 3,931	$ 14,928	$ 5,151
Effective tax rate	63.00%	42.00%	36.00%	15.00%
Increase in valuation allowance	$ 4,800		$ 3,600

Business Segment Information -

Business Segment Information - Segment Operating Results (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)segment	Sep. 30, 2018USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			2
Revenues:
Earnings in equity method investments	$ 14,426	$ 9,715	$ 57,051	$ 37,857
Total revenues	19,133	5,147	54,039	13,319
Total reported revenues	19,133	5,147
Segment operating income (loss):
Total segment operating income	(2,391)	32	(10,206)	(3,249)
453A interest	234	388	882	1,128
Decrease in inventories			4,566	0
Refined Coal
Revenues:
Earnings in equity method investments	14,426	9,715	57,051	37,857
Total revenues	4,385	4,104	12,796	10,857
Refined Coal | RMC6, LLC (RCM6)
Segment operating income (loss):
453A interest	200	400	900	1,100
Power Generation and Industrials
Revenues:
Earnings in equity method investments	0	0	0	0
Total revenues	14,010	1,043	39,612	2,462
Consumables
Revenues:
Total revenues	14,748	1,043	41,243	2,390
Consumables | Refined Coal
Revenues:
Total revenues	0	0	0	0
Consumables | Power Generation and Industrials
Revenues:
Total revenues	14,010	1,043	39,612	2,390
Other
Revenues:
Total revenues	0	0	0	72
Other | Refined Coal
Revenues:
Total revenues		0		0
Other | Power Generation and Industrials
Revenues:
Total revenues		0		72
Operating Segments
Revenues:
Total reported revenues	32,821	14,862	109,459	51,176
Segment operating income (loss):
Total segment operating income	17,181	11,630	59,836	42,282
Operating Segments | Refined Coal
Revenues:
Earnings in equity method investments	14,426	9,715	57,051	37,857
License royalties, related party	4,385	4,104	12,796	10,857
Total reported revenues	18,811	13,819	69,847	48,714
Segment operating income (loss):
Total segment operating income	18,158	12,798	68,137	45,775
Operating Segments | Power Generation and Industrials
Revenues:
Total reported revenues	14,010	1,043	39,612	2,462
Segment operating income (loss):
Total segment operating income	(977)	(1,168)	(8,301)	(3,493)
Decrease in inventories			4,700
Severance costs	1,900		4,500
Operating Segments | Consumables | Power Generation and Industrials
Revenues:
Total revenues	14,010	1,043	39,612	2,390
Operating Segments | Other | Power Generation and Industrials
Revenues:
Total revenues	0	0	0	72
Intersegment Eliminations | Refined Coal
Revenues:
Earnings in equity method investments	(14,426)	(9,715)	(57,051)	(37,857)
Corporate and Other
Revenues:
Total reported revenues	738	0	1,631	0
Segment operating income (loss):
Total segment operating income	$ (658)	$ 0	$ (1,409)	$ 0

Business Segment Information _2

Business Segment Information - Reconciliation of Reportable Segment Amounts (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Consolidated operating income	$ (2,391)			$ 32			$ (10,206)	$ (3,249)
Corporate payroll and benefits	(2,651)			(2,555)			(8,005)	(7,528)
Corporate legal and professional fees	(1,755)			(698)			(5,300)	(3,459)
Corporate general and administrative	(3,136)			(834)			(7,699)	(3,098)
Corporate depreciation and amortization	(2,043)			(74)			(4,902)	(262)
Other income (expense), net	212			86			342	146
Net income	3,923	$ 8,114	$ 14,402	5,503	$ 15,291	$ 7,662	26,439	28,456
Operating Segments
Segment Reporting Information [Line Items]
Consolidated operating income	17,181			11,630			59,836	42,282
All Other and Corporate
Segment Reporting Information [Line Items]
Consolidated operating income	(658)			0			(1,409)	0
Segment Reconciling Items
Segment Reporting Information [Line Items]
Consolidated operating income	16,523			11,630			58,427	42,282
Corporate payroll and benefits	(768)			(957)			(2,004)	(3,054)
Corporate legal and professional fees	(1,737)			(634)			(5,254)	(3,222)
Corporate general and administrative	(2,278)			(658)			(5,427)	(2,483)
Corporate depreciation and amortization	(21)			(23)			(41)	(97)
Corporate interest (expense) income, net	(1,413)			(10)			(4,668)	(18)
Other income (expense), net	212			86			334	199
Net income	$ 10,518			$ 9,434			$ 41,367	$ 33,607

Business Segment Information _3

Business Segment Information - Segment Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Assets:	$ 178,728	$ 159,664
Equity method investments	44,111	6,634
Operating Segments
Segment Reporting Information [Line Items]
Assets:	131,176	97,254
Operating Segments | Refined Coal
Segment Reporting Information [Line Items]
Assets:	49,055	11,468
Operating Segments | Power Generation and Industrials
Segment Reporting Information [Line Items]
Assets:	82,121	85,786
All Other and Corporate
Segment Reporting Information [Line Items]
Assets:	$ 47,552	$ 62,410

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cost method investment	$ 552	$ 552
Highview Obligation	207	213
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cost method investment	552	552
Highview Obligation	$ 207	$ 213

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	Dec. 07, 2018	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Time deposits, $250,000 or more		$ 250
ADA Carbon Solutions, LLC
Business Combination, Separately Recognized Transactions [Line Items]
Consideration transferred	$ 66,500

Restructuring - Narrative (Deta

Restructuring - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 0	$ 1,102	$ 0	$ 2,001
Employee Severance | ADA Carbon Solutions, LLC
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 600

Restructuring - Net Pretax Bene

Restructuring - Net Pretax Benefits (Charges), Incurred by Segment (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)employee	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)employee
Restructuring Cost and Reserve [Line Items]
Approximate Number of Employees | employee		7		13
Restructuring charges	$ 0	$ 1,102	$ 0	$ 2,001
Changes in estimates		0		0
Total pretax charge, net of reversals		1,102		2,001
Operating Segments | Refined Coal
Restructuring Cost and Reserve [Line Items]
Restructuring charges		168		448
Changes in estimates		0		0
Total pretax charge, net of reversals		168		448
Operating Segments | Power Generation and Industrials
Restructuring Cost and Reserve [Line Items]
Restructuring charges		500		996
Changes in estimates		0		0
Total pretax charge, net of reversals		500		996
All Other and Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring charges		434		557
Changes in estimates		0		0
Total pretax charge, net of reversals		$ 434		$ 557

Restructuring - Utilization of

Restructuring - Utilization of Restructuring Accruals (Details) - Employee Severance $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Restructuring Reserve [Roll Forward]
Remaining accrual as of December 31, 2017	$ 2,208
Expense provision	233
Cash payments and other	(1,758)
Change in estimates	(104)
Remaining accrual as of September 30, 2019	$ 579

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	Nov. 12, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Nov. 30, 2018
Subsequent Event [Line Items]
Dividends declared (in dollars per share)		$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.75	$ 0.75
Common Stock
Subsequent Event [Line Items]
Remaining authorized amount		$ 2,900,000						$ 2,900,000
Maximum | Common Stock
Subsequent Event [Line Items]
Authorized amount										$ 20,000,000
Subsequent Event
Subsequent Event [Line Items]
Dividends declared (in dollars per share)	$ 0.25
Authorized incremental amount	$ 7,100,000

Uncategorized Items - ades-2019

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 2,950,000
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	28,817,000
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	2,950,000
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 28,817,000