Ecovyst (ECVT) 10-Q 14 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2017	Nov. 10, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	PQ Group Holdings Inc.
Entity Central Index Key	1,708,035
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		135,240,826

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 68,838	$ 70,742
Receivables, net	212,018	160,581
Inventories	235,921	227,048
Prepaid and other current assets	29,010	34,307
Total current assets	545,787	492,678
Investments in affiliated companies	479,366	459,406
Property, plant and equipment, net	1,209,047	1,181,388
Goodwill	1,306,547	1,241,429
Other intangible assets, net	800,423	816,573
Other long-term assets	74,433	68,197
Total assets	4,415,603	4,259,671
LIABILITIES
Notes payable and current maturities of long-term debt	54,255	14,481
Accounts payable	129,793	128,478
Accrued liabilities	112,788	99,433
Total current liabilities	296,836	242,392
Long-term debt	2,597,481	2,547,717
Deferred income taxes	319,738	318,463
Other long-term liabilities	120,578	123,155
Total liabilities	3,334,633	3,231,727
Commitments and contingencies (Note 16)
EQUITY
Common stock ($0.01 par); authorized shares 450,000,000; issued shares 106,219,759 and 106,452,330 on September 30, 2017 and December 31, 2016, respectively; outstanding shares 104,109,932 and 106,430,811 on September 30, 2017 and December 31, 2016, respectively	1,062	73
Preferred stock ($0.01 par); authorized shares 50,000,000; no shares issued or outstanding on September 30, 2017 and December 31, 2016	0	0
Additional paid-in capital	1,169,778	1,167,137
Accumulated deficit	(97,788)	(90,380)
Treasury stock, at cost; shares 21,519 on December 31, 2016	0	(239)
Accumulated other comprehensive income (loss)	2,978	(53,711)
Total PQ Group Holdings Inc. equity	1,076,030	1,022,880
Noncontrolling interest	4,940	5,064
Total equity	1,080,970	1,027,944
Total liabilities and equity	$ 4,415,603	$ 4,259,671

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	450,000,000	450,000,000
Common stock, shares issued (shares)	106,219,759	106,452,330
Common stock, shares outstanding (shares)	104,109,932	103,947,887
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)	50,000,000	50,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Treasury stock (shares)		21,519

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Sales	$ 391,829	$ 369,979	$ 1,114,027	$ 741,446
Cost of goods sold	289,270	274,680	821,342	557,748
Gross profit	102,559	95,299	292,685	183,698
Selling, general and administrative expenses	36,169	36,003	105,907	74,017
Other operating expense, net	19,833	15,042	47,156	40,630
Operating income	46,557	44,254	139,622	69,051
Equity in net (income) loss from affiliated companies	(10,257)	4,616	(24,879)	9,309
Interest expense	49,079	48,610	144,041	94,362
Debt extinguishment costs	453	0	453	11,858
Other expense, net	5,126	4,170	21,739	7,194
Income (loss) before income taxes and noncontrolling interest	2,156	(13,142)	(1,732)	(53,672)
Provision for (benefit from) income taxes	5,172	(3,536)	5,269	36,013
Net loss	(3,016)	(9,606)	(7,001)	(89,685)
Less: Net income attributable to the noncontrolling interest	329	411	407	725
Net loss attributable to PQ Group Holdings Inc.	$ (3,345)	$ (10,017)	$ (7,408)	$ (90,410)
Net loss per common share:
Basic loss per share (usd per share)	$ (0.03)	$ (0.10)	$ (0.07)	$ (1.10)
Diluted loss per share (usd per share)	$ (0.03)	$ (0.10)	$ (0.07)	$ (1.10)
Weighted average shares outstanding:
Basic (shares)	104,096,837	103,783,719	104,020,180	81,986,221
Diluted (shares)	104,096,837	103,783,719	104,020,180	81,986,221

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (3,016)	$ (9,606)	$ (7,001)	$ (89,685)
Other comprehensive income (loss), net of tax:
Pension and postretirement benefits	(20)	162	(223)	486
Net (loss) gain from hedging activities	(301)	201	(3,326)	1,302
Foreign currency translation	18,850	1,286	60,492	(7,919)
Total other comprehensive income (loss)	18,529	1,649	56,943	(6,131)
Comprehensive income (loss)	15,513	(7,957)	49,942	(95,816)
Less: Comprehensive income (loss) attributable to noncontrolling interests	82	(165)	661	(165)
Comprehensive income (loss) attributable to PQ Group Holdings Inc.	$ 15,431	$ (7,792)	$ 49,281	$ (95,651)

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated deficit	Treasury stock, at cost	Accumulated other comprehensive income (loss)	Non-controlling interest
Beginning balance at Dec. 31, 2015	$ 235,293	$ 0	$ 245,279	$ (10,634)	$ 0	$ 648	$ 0
Increase (Decrease) in Stockholders' Equity
Business Combination	918,769	73	912,127				6,569
Net income (loss)	(89,685)			(90,410)			725
Other comprehensive income (loss)	(6,131)					(5,518)	(613)
Stock repurchase	(2,540)				(2,540)
Equity contribution	6,600		6,486		114
Dividend distribution	(476)						(476)
Stock compensation expense	4,903		2,666		2,237
Ending balance at Sep. 30, 2016	1,066,733	73	1,166,558	(101,044)	(189)	(4,870)	6,205
Beginning balance at Dec. 31, 2016	1,027,944	73	1,167,137	(90,380)	(239)	(53,711)	5,064
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(7,001)			(7,408)			407
Stock split and conversion		989	(1,228)		239
Other comprehensive income (loss)	56,943					56,689	254
Dividend distribution	(785)						(785)
Stock compensation expense	3,869		3,869
Ending balance at Sep. 30, 2017	$ 1,080,970	$ 1,062	$ 1,169,778	$ (97,788)	$ 0	$ 2,978	$ 4,940

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income (loss)	$ (7,001)	$ (89,685)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation	89,987	60,173
Amortization	39,148	25,429
Acquisition accounting valuation adjustments on inventory sold	871	23,518
Amortization of deferred financing costs and original issue discount	6,626	4,443
Debt extinguishment costs	253	7,182
Debt modification creditor fees capitalized	0	(1,932)
Foreign currency exchange loss	21,612	6,240
Pension and postretirement healthcare benefit expense	2,642	2,741
Pension and postretirement healthcare benefit funding	(7,525)	(2,258)
Deferred income tax (benefit) expense	(12,447)	18,741
Net loss on asset disposals	6,419	2,288
Supplemental pension plan mark-to-market gain	(708)	(393)
Stock compensation	3,869	4,904
Equity in net (income) loss from affiliated companies	(24,879)	9,309
Dividends received from affiliated companies	19,071	136
Working capital changes that provided (used) cash, excluding the effect of business combinations:
Receivables	(28,900)	3,483
Inventories	4,897	13,832
Prepaids and other current assets	(6,000)	(824)
Accounts payable	(9,044)	(7,332)
Accrued liabilities	13,460	10,125
Other, net	(2,535)	(812)
Net cash provided by operating activities	109,816	89,308
Cash flows from investing activities:
Purchases of property, plant and equipment	(90,229)	(69,798)
Investment in affiliated companies	(9,000)	0
Change in restricted cash, net	12,135	(6,199)
Loan receivable under the New Markets Tax Credit Arrangement	(6,221)	(7,823)
Business combinations, net of cash acquired	(41,572)	(1,777,740)
Other, net	391	0
Net cash used in investing activities	(134,496)	(1,861,560)
Cash flows from financing activities:
Draw down of revolver	302,725	118,000
Repayments of revolver	(270,088)	(125,000)
Issuance of long-term debt under the New Market Tax Credit arrangement	8,820	11,000
Issuance of long-term debt, net of original issue discount and financing fees	0	1,172,980
Issuance of long-term notes, net of original issue discount and financing fees	0	1,123,777
Debt issuance costs	(1,205)	(5,397)
Repayments of long-term debt	(10,289)	(475,998)
Interest hedge premium	0	(1,551)
Equity contribution	0	6,600
Stock repurchase	0	(2,540)
Distributions to noncontrolling interests	(785)	(476)
Net cash provided by financing activities	29,178	1,821,395
Effect of exchange rate changes on cash and cash equivalents	(6,402)	(2,375)
Net change in cash and cash equivalents	(1,904)	46,768
Cash and cash equivalents at beginning of period	70,742	25,155
Cash and cash equivalents at end of period	68,838	71,923
Supplemental cash flow information:
Cash paid for taxes	21,005	10,740
Cash paid for interest	118,793	56,932
Non-cash investing activity:
Capital expenditures acquired on account but unpaid as of the period end	12,924	14,875
Non-cash financing activity:
Equity consideration for the Business Combination	0	910,800
Debt assumed in the Business Combination	$ 16,609	$ 22,911

Background and Basis of Present

Background and Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis of Presentation	Background and Basis of Presentation: Description of Business PQ Group Holdings Inc. and subsidiaries (the “Company” or “PQ Group Holdings”) conducts operations through two principal segments: (1) Performance Materials & Chemicals: a fully integrated, global leader in silicate technology, producing sodium silicate, specialty silicas, zeolites, spray dry silicates, magnesium silicate, and other high performance chemical products used in a variety of end-uses such as adsorbents for surface coatings, clarifying agents for beverages, cleaning and personal care products and engineered glass products for use in highway safety, polymer additives, metal finishing and electronics end uses; and (2) Environmental Catalysts & Services: a leading global innovator and producer of silica catalysts used in the production of high-density polyethylene (“HDPE”), methyl methacrylate (“MMA”), specialty zeolite-based catalysts sold to the emissions control industry, the petrochemical industry and other areas of the broader chemicals industry and a merchant sulfuric acid producer operating a network of plants serving a variety of end uses, including the oil refining, nylon, mining, general industrial and chemical industries. The Company experiences some seasonality, primarily with respect to the performance materials and refining services product groups. With respect to the performance materials product group, sales and earnings are generally higher during the second and third quarters of the year as highway striping projects typically occur during warmer weather months. Additionally, the refining services product group typically experiences similar seasonal fluctuations as a result of higher demand for gasoline products in the summer months. As a result, working capital requirements tend to be higher in the first and fourth quarters of the year, while higher cash generation occurs in the second and third quarters of the year. Basis of Presentation On August 17, 2015, the Company, PQ Holdings Inc. (“PQ Holdings”), Eco Services Operations LLC (“Eco Services”), certain investment funds affiliated with CCMP Capital Advisors, LLC (now known as CCMP Capital Advisors, LP; “CCMP”), and stockholders of PQ Holdings and Eco Services entered into a reorganization and transaction agreement pursuant to which the companies consummated a series of transactions to reorganize and combine the businesses of PQ Holdings and Eco Services (the “Business Combination”), under a new holding company, PQ Group Holdings Inc. The Business Combination was consummated on May 4, 2016. In accordance with accounting principles generally accepted in the United States (“GAAP”), Eco Services is the accounting predecessor to PQ Group Holdings. Certain investment funds affiliated with CCMP held a controlling interest position in Eco Services prior to the Business Combination. In addition, certain investment funds affiliated with CCMP owned a non-controlling interest in PQ Holdings prior to the Business Combination and the merger with Eco Services constituted a change in control under the PQ Holdings credit agreements and bond indenture that were in place at the time of the Business Combination. Therefore, Eco Services is deemed to be the accounting acquirer. These condensed consolidated financial statements are the continuation of Eco Services’ business prior to the Business Combination. The condensed consolidated financial statements included herein are unaudited. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations for interim reporting. In the opinion of management, all adjustments of a normal and recurring nature necessary to state fairly the financial position and results of operations have been included. The results of operations are not necessarily indicative of the results to be expected for the full year. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s prospectus dated September 28, 2017, as filed with the SEC pursuant to Rule 424(b) under the Securities Act of 1933, as amended. The Company has continued to follow the accounting policies set forth in those consolidated financial statements. Prior to September 22, 2017, the Company had two classes of common stock designated as Class A and Class B common stock. On September 22, 2017, the Company reclassified its Class A common stock into common stock and then effected a 8.8275 -for-1 split of its common stock. On September 28, 2017, the Company converted each outstanding share of Class B common stock into 8.8275 shares of common stock plus an additional number of shares determined by dividing the unreturned paid-in capital amount of such Class B common stock, or $113.74 per share, by $17.50 , the initial public offering price of a share of our common stock in the Company’s initial public offering (“IPO”), rounded to the nearest whole share. Holders of Class B common stock did not receive any cash payments from the Company in connection with the conversion of the Class B common stock. On October 3, 2017, the Company completed its IPO whereby it issued 29,000,000 shares of its common stock at an initial public offering price of $17.50 per share. The shares began trading on the New York Stock Exchange on September 29, 2017. The aggregate proceeds received by the Company from the offering were approximately $480,525 , net of underwriting discounts, commissions and estimated offering expenses. The net proceeds were used to repay existing indebtedness as further described in Note 20.

New Accounting Standards

New Accounting Standards	9 Months Ended
	Sep. 30, 2017
Accounting Changes and Error Corrections [Abstract]
New Accounting Standards	New Accounting Standards: Recently Adopted Accounting Standards In October 2016, the Financial Accounting Standards Board (“FASB”) issued guidance which eliminates the deferral of the tax effects of intra-entity transfers of an asset other than inventory. Previous GAAP prohibited the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset had been sold to an outside party which has resulted in diversity in practice and increased complexity within financial reporting. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company early adopted the guidance effective January 1, 2017. The guidance did not have a material impact on the Company’s consolidated financial statements. In March 2016, the FASB issued guidance that includes targeted improvements to the accounting for employee stock-based compensation. The updates in the guidance include changes in the income tax consequences, balance sheet classification and cash flow statement reporting of stock-based payment transactions. The guidance also includes certain modifications applicable only to nonpublic entities. For public companies, the new guidance is effective for annual periods beginning after December 15, 2016, and interim periods within those years. The Company adopted this new guidance as required on January 1, 2017, with no material impact upon adoption to the Company’s consolidated financial statements. On a prospective basis from the adoption date, the Company will record all tax effects related to stock-based compensation through the statement of operations, and all tax-related cash flows resulting from stock-based award payments will be reported as operating activities in the statement of cash flows. The Company made an accounting policy election under the new guidance to account for forfeitures of stock-based compensation awards as they occur. In July 2015, the FASB issued new guidance that changes the measurement principle for inventory from the lower of cost or market to the lower of cost or net realizable value. The amendments in this guidance do not apply to inventory that is measured using LIFO or the retail inventory method; rather, the amendments apply to all other inventory, which includes inventory that is measured using FIFO or average cost. Within the scope of this new guidance, an entity should measure inventory at the lower of cost or net realizable value. Net realizable value is defined as the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation, which is consistent with existing GAAP. The Company adopted the new guidance on January 1, 2017 as required. The guidance did not have a material impact on the Company’s consolidated financial statements. Accounting Standards Not Yet Adopted In August 2017, the FASB issued amendments intended to better align hedge accounting with an entities risk management activities. The amendments expand hedge accounting for non-financial and financial risk components and revise the measurement methodologies to better align with an entities risk management activities. Separate presentation of hedge ineffectiveness is eliminated to provide greater transparency of the full impact of hedging by requiring presentation of the results of the hedged item and hedging instrument in a single financial statement line item. In addition, the amendments reduce complexity by simplifying the manner in which assessments of hedge effectiveness may be performed. The new guidance is effective for public companies for annual periods beginning after December 15, 2018, including interim periods within those years. Early adoption is permitted, and the new guidance should be applied prospectively to the presentation and disclosure guidance. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In May 2017, the FASB issued guidance to clarify which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. Under the new guidance, an entity should not account for the effects of a change in a share-based payment award using modification accounting unless the fair value, vesting conditions and classification as either a liability or equity are all the same with respect to the award immediately prior to modification and the modified award itself. The new guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those years. Early adoption is permitted, and the new guidance should be applied prospectively to awards modified on or after the adoption date. Based on the Company’s existing policies regarding the application of modification accounting to its share-based payment awards, the Company does not believe that the new guidance will have a material impact on its consolidated financial statements. In March 2017, the FASB issued guidance to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost (collectively, “pension costs”). Under current GAAP, there are several components of pension costs which are presented net to arrive at pension costs as included in the income statement and disclosed in the notes. As part of this amendment to the existing guidance, the service cost component of pension costs will be bifurcated from the other components and included in the same line item of the income statement as compensation costs are reported. The remaining components will be reported together below operating income on the income statement, either as a separate line item or combined with another line item on the income statement and disclosed. Additionally, with respect to capitalization to inventory, fixed assets, etc., only the service cost component will be eligible for capitalization upon adoption of the guidance. The new guidance is effective for public companies for annual periods beginning after December 15, 2017, including interim periods within those years. Early adoption is permitted. The amendments should be applied retrospectively upon adoption with respect to the presentation of the service and other cost components of pension costs in the income statement, and prospectively for the capitalization of the service cost component in assets. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In January 2017, the FASB issued guidance which eliminates the second step from the traditional two-step goodwill impairment test. Under current guidance, an entity performed the first step of the goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount; if an impairment loss was indicated, the entity computed the implied fair value of goodwill to determine whether an impairment loss existed, and if so, the amount to recognize. Under the new guidance, an impairment loss is recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value (the Step 1 test), with no further testing required. Any impairment loss recognized is limited to the amount of goodwill allocated to the reporting unit. The new guidance is effective for public companies that are SEC registrants for fiscal years beginning after December 15, 2019, with early adoption permitted for goodwill impairment tests performed on testing dates after January 1, 2017. All entities are required to apply the guidance prospectively to goodwill impairment tests subsequent to adoption of the standard. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In January 2017, the FASB issued guidance which clarifies the definition of a business and provides revised criteria and a framework to determine whether an integrated set of assets and activities is a business. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those years. Early adoption is permitted. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In November 2016, the FASB issued guidance which clarifies the classification and presentation of changes in restricted cash on the statement of cash flows. The updates in the guidance require that the statement of cash flows explain the change during the period in the total of cash, cash equivalents and restricted cash when reconciling the beginning-of-period and end-of-period total amounts. The updates also require a reconciliation between cash, cash equivalents and restricted cash presented on the balance sheet to the total of the same amounts presented on the statement of cash flows. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those years. Early adoption is permitted, and the new guidance should be applied retrospectively to each period presented. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. As of September 30, 2017 , the Company had $ 1,645 of restricted cash included in prepaid and other current assets on its balance sheet related to its New Market Tax Credit financing arrangements as well as other small restricted cash balances. In August 2016, the FASB issued guidance which clarifies the classification of certain cash receipts and cash payments in the statement of cash flows, including debt prepayment or extinguishment costs and distributions from certain equity method investees. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, and the new guidance should be applied retrospectively to each period presented. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In February 2016, the FASB issued guidance that amends the accounting for leases. Under the new guidance, a lessee will recognize assets and liabilities for most leases (including those classified under existing GAAP as operating leases, which based on current standards are not reflected on the balance sheet), but will recognize expenses similar to current lease accounting. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. Early adoption is permitted. The new guidance must be adopted using a modified retrospective transition and provides for certain practical expedients. The Company is currently evaluating the impact that the new guidance will have on its consolidated financial statements. The Company has operating lease agreements for which it expects to recognize right of use assets and corresponding liabilities on its balance sheet upon adoption of the new guidance. A complete discussion of these leases is included in the Company’s audited consolidated financial statements for the year ended December 31, 2016 in Note 20, Commitments and Contingent Liabilities. In May 2014, the FASB issued accounting guidance (with subsequent targeted amendments) that will significantly enhance comparability of revenue recognition practices across entities, industries, jurisdictions and capital markets. The core principle of the guidance is that revenue recognized from a transaction or event that arises from a contract with a customer should reflect the consideration to which an entity expects to be entitled in exchange for goods or services provided. To achieve that core principle, the new guidance sets forth a five-step revenue recognition model that will need to be applied consistently to all contracts with customers, except those that are within the scope of other topics in the Accounting Standards Codification (“ASC”). Also required are enhanced disclosures to help users of financial statements better understand the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. The enhanced disclosures include qualitative and quantitative information about contracts with customers, significant judgments made in applying the revenue guidance, and assets recognized related to the costs to obtain or fulfill a contract. For public companies, the new requirements are effective for annual reporting periods beginning after December 15, 2017, including interim periods within those years. The Company is reviewing its key revenue streams and assessing the underlying customer contracts within the framework of the new guidance. The Company has evaluated the key aspects of its revenue streams for impact under the new guidance and is currently performing a detailed analysis of its customer agreements to quantify the potential changes under the guidance. The Company believes that the guidance will not have a material impact on its existing revenue recognition practices, but there are new robust disclosure requirements that will have an impact on the Company’s reporting. The Company anticipates adopting the new guidance in the first quarter of 2018 as required, and expects to implement the guidance under the modified retrospective transition method of adoption.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements: Fair values are based on quoted market prices when available. When market prices are not available, fair values are generally estimated using discounted cash flow analyses, incorporating current market inputs for similar financial instruments with comparable terms and credit quality. In instances where there is little or no market activity for the same or similar instruments, the Company estimates fair values using methods, models and assumptions that management believes a hypothetical market participant would use to determine a current transaction price. These valuation techniques involve some level of management estimation and judgment that becomes significant with increasingly complex instruments or pricing models. Where appropriate, adjustments are included to reflect the risk inherent in a particular methodology, model or input used. The Company’s financial assets and liabilities carried at fair value have been classified based upon a fair value hierarchy. The hierarchy gives the highest ranking to fair values determined using unadjusted quoted prices in active markets for identical assets and liabilities (Level 1) and the lowest ranking to fair values determined using methodologies and models with unobservable inputs (Level 3). The classification of an asset or a liability is based on the lowest level input that is significant to its measurement. For example, a Level 3 fair value measurement may include inputs that are both observable (Levels 1 and 2) and unobservable (Level 3). The levels of the fair value hierarchy are as follows: • Level 1—Values are unadjusted quoted prices for identical assets and liabilities in active markets accessible at the measurement date. Active markets provide pricing data for trades occurring at least weekly and include exchanges and dealer markets. • Level 2—Inputs include quoted prices for similar assets or liabilities in active markets, quoted prices from those willing to trade in markets that are not active, or other inputs that are observable or can be corroborated by market data for the term of the instrument. Such inputs include market interest rates and volatilities, spreads and yield curves. • Level 3—Certain inputs are unobservable (supported by little or no market activity) and significant to the fair value measurement. Unobservable inputs reflect the Company’s best estimate of what hypothetical market participants would use to determine a transaction price for the asset or liability at the reporting date. The following table presents information about the Company’s assets and liabilities that were measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 , and indicates the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. As of September 30, 2017 Quoted Prices in Significant Other Significant (Level 3) Assets: Derivative contracts $ 1,098 $ — $ 1,098 $ — Restoration plan assets 5,566 5,566 — — Total $ 6,664 $ 5,566 $ 1,098 $ — Liabilities: Derivative contracts $ 58 $ — $ 58 $ — As of December 31, 2016 Quoted Prices in Significant Other Significant (Level 3) Assets: Derivative contracts $ 6,434 $ — $ 6,434 $ — Restoration plan assets 5,594 5,594 — — Total $ 12,028 $ 5,594 $ 6,434 $ — Restoration plan assets The fair values of the Company’s restoration plan assets are determined through quoted prices in active markets. Restoration plan assets are assets held in a Rabbi trust to fund the obligations of the Company’s defined benefit supplementary retirement plans and include various stock and fixed income mutual funds. See Note 15 to these condensed consolidated financial statements regarding defined supplementary retirement plans. Derivative contracts Derivative assets and liabilities can be exchange-traded or traded over-the-counter (“OTC”). The Company generally values exchange-traded derivatives using models that calibrate to market transactions and eliminate timing differences between the closing price of the exchange-traded derivatives and their underlying instruments. OTC derivatives are valued using market transactions and other market evidence whenever possible, including market-based inputs to models, model calibration to market transactions, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency. When models are used, the selection of a particular model to value an OTC derivative depends on the contractual terms of, and specific risks inherent in, the instrument as well as the availability of pricing information in the market. The Company generally uses similar models to value similar instruments. Valuation models require a variety of inputs, including contractual terms, market prices and rates, forward curves, measures of volatility, and correlations of such inputs. For OTC derivatives that trade in liquid markets, such as forward contracts, swaps and options, model inputs can generally be corroborated by observable market data by correlation or other means, and model selection does not involve significant management judgment. The Company has interest rate caps and natural gas caps and swaps that are fair valued using Level 2 inputs. In addition, the Company applies a credit valuation adjustment to reflect credit risk which is calculated based on credit default swaps. To the extent that the Company’s net exposure under a specific master agreement is an asset, the Company utilizes the counterparty’s default swap rate. If the net exposure under a specific master agreement is a liability, the Company utilizes a default swap rate comparable to PQ Group Holdings. The credit valuation adjustment is added to the discounted fair value to reflect the exit price that a market participant would be willing to receive to assume the Company’s liabilities or that a market participant would be willing to pay for the Company’s assets. As of September 30, 2017 and December 31, 2016 , the credit valuation adjustment resulted in a minimal change in the fair value of the derivatives.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss): The following table presents the tax effects of each component of other comprehensive income (loss) for the three and nine months ended September 30, 2017 and 2016 : Three months ended September 30, 2017 2016 Pre-tax Tax After-tax Pre-tax Tax After-tax Defined benefit and other postretirement plans Amortization and unrealized losses $ (33 ) $ 13 $ (20 ) $ 162 $ — $ 162 Benefit plans, net (33 ) 13 (20 ) 162 — 162 Net loss (gain) from hedging activities (486 ) 185 (301 ) 324 (123 ) 201 Foreign currency translation 21,343 (2,493 ) 18,850 1,930 (644 ) 1,286 Other comprehensive income (loss) $ 20,824 $ (2,295 ) $ 18,529 $ 2,416 $ (767 ) $ 1,649 Nine months ended September 30, 2017 2016 Pre-tax Tax After-tax Pre-tax Tax After-tax Defined benefit and other postretirement plans Amortization and unrealized losses $ (261 ) $ 38 $ (223 ) $ 486 $ — $ 486 Benefit plans, net (261 ) 38 (223 ) 486 — 486 Net loss (gain) from hedging activities (5,373 ) 2,047 (3,326 ) 2,100 (798 ) 1,302 Foreign currency translation 69,202 (8,710 ) 60,492 (9,605 ) 1,686 (7,919 ) Other comprehensive income (loss) $ 63,568 $ (6,625 ) $ 56,943 $ (7,019 ) $ 888 $ (6,131 ) The following table presents the change in accumulated other comprehensive income (loss), net of tax, by component for the nine months ended September 30, 2017 and 2016 : Defined benefit Net gain (loss) Foreign Total December 31, 2016 $ 7,513 $ 4,557 $ (65,781 ) $ (53,711 ) Other comprehensive income (loss) before reclassifications (322 ) (3,404 ) 60,238 56,512 Amounts reclassified from accumulated other comprehensive income (a) 99 78 — 177 Net current period other comprehensive income (loss) (223 ) (3,326 ) 60,238 56,689 September 30, 2017 $ 7,290 $ 1,231 $ (5,543 ) $ 2,978 December 31, 2015 $ 648 $ — $ — $ 648 Other comprehensive income (loss) before reclassifications 486 591 (7,306 ) (6,229 ) Amounts reclassified from accumulated other comprehensive income (a) — 711 — 711 Net current period other comprehensive income (loss) 486 1,302 (7,306 ) (5,518 ) September 30, 2016 $ 1,134 $ 1,302 $ (7,306 ) $ (4,870 ) ————— (a) See the following table for details about these reclassifications. The following table presents the reclassifications out of accumulated other comprehensive income (loss) for the three and nine months ended September 30, 2017 and 2016 . Amounts in parenthesis indicate debits to profit/loss. Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Affected Line Item in the Three months ended Nine months ended 2017 2016 2017 2016 Defined benefit and other postretirement plans Amortization of prior service cost $ 20 $ — $ 60 $ — (a) Amortization of net gain (loss) 19 — 58 — (a) 39 — 118 — Total before tax (6 ) — (19 ) — Tax (expense) benefit $ 33 $ — $ 99 $ — Net of tax Net gain (loss) from hedging activities Interest rate caps $ 13 $ (2 ) $ 22 $ (2 ) Interest expense Natural gas swaps 94 420 104 1,148 Cost of goods sold 107 418 126 1,146 Total before tax (41 ) (159 ) (48 ) (435 ) Tax (expense) benefit $ 66 $ 259 $ 78 $ 711 Net of tax Total reclassifications for the period $ 99 $ 259 $ 177 $ 711 Net of tax ————— (a) These accumulated other comprehensive income (loss) components are included in the computation of net periodic pension and other postretirement cost (see Note 15 to these condensed consolidated financial statements for additional details).

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Acquisitions	Acquisition: On June 12, 2017 (the “Closing Date”), the Company acquired the facilities of Sovitec Mondial S.A. (“Sovitec”) located in Belgium, Spain, Argentina and France as part of a stock transaction (the “Acquisition”) for $41,572 in cash, excluding assumed debt. Based in Fleurus, Belgium, Sovitec is a high quality producer of engineered glass products used in transportation safety, metal finishing and polymer additives. The Acquisition was accounted for using the acquisition method of accounting. Under the acquisition method, the purchase price was allocated to the identifiable net assets acquired based on the fair values of the identifiable assets acquired and liabilities assumed as of the Closing Date. The excess of the purchase price over the fair values of the identifiable net assets acquired was recorded to goodwill. The following table sets forth the calculation and preliminary allocation of the purchase price to the identifiable net assets acquired with respect to the Acquisition: Total consideration, net of cash acquired $ 41,572 Recognized amounts of identifiable assets acquired and liabilities assumed: Receivables $ 14,305 Inventories 7,645 Prepaid and other current assets 230 Property, plant and equipment 9,020 Other long-term assets 129 Fair value of assets acquired 31,329 Current debt (6,420 ) Accounts payable (10,748 ) Long-term debt (10,189 ) Other long-term liabilities (154 ) Fair value of net assets acquired 3,818 Goodwill 37,754 $ 41,572 The valuation of the identifiable assets and liabilities included in the table above is preliminary and is subject to change, as the Company is in the process of evaluating the information required to determine the fair values of certain identifiable assets and liabilities acquired, including inventory, property, plant and equipment, and intangible assets. An increased portion of the purchase price allocated to the identifiable net assets acquired will reduce the amount recognized for goodwill and may result in increased cost of goods sold, depreciation and/or amortization expense. Adjustments to the provisional amounts during the measurement period that result in changes to depreciation, amortization or other income effects will be recognized in the reporting period(s) in which the adjustments are determined. The Company’s condensed consolidated financial statements include Sovitec’s results of operations for the period from the Closing Date through September 30, 2017 . Net sales and net income attributable to Sovitec during this period are included in the Company’s condensed consolidated statement of operations and total $13,490 and $644 , respectively, for the three months ended September 30, 2017 , and $17,194 and $1,148 , respectively, for the nine months ended September 30, 2017 . Acquisition costs of $737 and $2,065 are included in other operating expense, net in the Company’s condensed consolidated statement of operations for the three and nine months ended September 30, 2017 , respectively. The Company believes that the Acquisition will enable it to offer a more comprehensive, cost-effective and high-quality portfolio of products and services to its customers worldwide when, combined with anticipated synergies within its existing business, contributed to a total purchase price that resulted in the recognition of goodwill. All of the goodwill was assigned to the Company’s Performance Materials and Chemicals segment. The goodwill associated with the Acquisition is not deductible for tax purposes. Pro Forma Financial Information The unaudited pro forma financial information for the three months ended September 30, 2016 and the nine months ended September 30, 2017 and 2016 has been derived from the Company’s historical consolidated financial statements and prepared to give effect to the Acquisition, assuming that the Acquisition occurred on January 1, 2016. The unaudited pro forma consolidated results of operations are provided for illustrative purposes only and are not indicative of the Company’s actual consolidated results of operations had the Acquisition been made as of January 1, 2016. The unaudited pro forma results of operations do not reflect any operating efficiencies or potential cost savings which may result from the Acquisition. The results of operations for the three months ended September 30, 2017 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Three months ended September 30, Nine months ended 2016 2017 2016 (unaudited) Pro forma sales $ 381,065 $ 1,130,454 $ 772,549 Pro forma net loss (8,289 ) (6,511 ) (88,300 ) Certain non-recurring charges included in the Company’s results of operations for the nine months ended September 30, 2017 were allocated to the respective prior year periods for pro forma purposes. For the nine months ended September 30, 2017 , non-recurring charges allocated to the prior year period include transaction fee charges of $2,065 which were excluded from the pro forma net loss for the nine months ended September 30, 2017 . Business Combination: As described in Note 1 to these condensed consolidated financial statements, on May 4, 2016, the Company, PQ Holdings, Eco Services, certain investment funds affiliated with CCMP and certain other stockholders of PQ Holdings and Eco Services completed the Business Combination. Eco Services is the accounting predecessor to PQ Group Holdings. Certain investment funds affiliated with CCMP held a controlling interest position in Eco Services prior to the Business Combination. In addition, certain investment funds affiliated with CCMP owned a noncontrolling interest in PQ Holdings prior to the Business Combination and the merger with Eco constituted a change in control under the various PQ Holdings credit agreements and bond indenture. Therefore, Eco Services is deemed to be the accounting acquirer. These condensed consolidated financial statements are the continuation of Eco Services’ business prior to the Business Combination. Total consideration for the Business Combination included $1,777,740 of cash, $910,800 of equity in the acquired PQ Holdings entities and $1,401 of assumed stock awards of PQ Holdings. The fair value of the equity consideration was determined based on an estimated enterprise value using a market approach as of the date of the Business Combination, reduced by borrowings to arrive at the fair value of equity. The existing PQ Holdings credit facilities were not legally assumed as part of the Business Combination and the extinguishment of the debt concurrent with the Business Combination was included as part of the consideration transferred. The Company’s condensed consolidated financial statements include PQ Holdings results of operations from May 4, 2016 through September 30, 2016 . Net sales and net loss attributable to PQ Holdings during this period are included in the Company’s condensed consolidated statement of operations and total $276,726 and $29,070 for the three months ended September 30, 2016 and $462,097 and $122,497 for the nine months ended September 30, 2016 . Acquisition costs of $896 and $1,398 are included in other operating expense, net in the Company’s consolidated statement of operations for the three and nine months ended September 30, 2016 , respectively. In accordance with the requirements of the purchase method of accounting for acquisitions, inventories were recorded at fair market value (which is defined as estimated selling prices less the sum of (a) costs of disposal and (b) a reasonable profit allowance for the selling effort of the acquiring entity), which was $58,683 higher than the historical cost. The Company’s cost of goods sold includes a pre-tax charge of $5,804 and $23,518 for the three and nine months ended September 30, 2016 , respectively, relating to the portion of the step-up on inventory sold during the period. A separate portion of the fair value step-up related to the domestic inventory accounted for under the LIFO method was included in inventory on the consolidated balance sheet as of December 31, 2016 as part of the new LIFO base layer on the acquired inventory. Pro Forma Financial Information The unaudited pro forma financial information for the nine months ended September 30, 2016 has been derived from the Company’s historical consolidated financial statements and prepared to give effect to the Business Combination, assuming that the Business Combination occurred on January 1, 2015. These pro forma adjustments primarily relate to incremental depreciation expense on the step up of fixed assets, amortization of acquired intangibles, higher cost of goods sold related to the sale of revalued inventory, incremental interest expense related to the additional debt that needed to fund the Business Combination, and the estimated impact of these adjustments on the Company’s tax provision. The unaudited pro forma consolidated results of operations are provided for illustrative purposes only and are not indicative of the Company’s actual consolidated results of operations had the Business Combination been made as of January 1, 2015. The unaudited pro forma results of operations do not reflect any operating efficiencies or potential cost savings which may result from the Business Combination. The results of operations for the three months ended September 30, 2016 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Nine months ended September 30, 2016 (unaudited) Pro forma sales $ 1,080,310 Pro forma net loss (55,985 ) Certain non-recurring charges included in the Company’s results of operations for the nine months ended September 30, 2016 were allocated to the respective prior year periods for pro forma purposes. For the nine months ended September 30, 2016 , non-recurring charges allocated to the prior year period include a debt prepayment penalty of $26,250 , refinancing charges of $4,616 and transaction fee charges of $714 , all of which are excluded from the pro forma net loss for the nine months ended September 30, 2016 .

Business Combination

Business Combination	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Business Combination	Acquisition: On June 12, 2017 (the “Closing Date”), the Company acquired the facilities of Sovitec Mondial S.A. (“Sovitec”) located in Belgium, Spain, Argentina and France as part of a stock transaction (the “Acquisition”) for $41,572 in cash, excluding assumed debt. Based in Fleurus, Belgium, Sovitec is a high quality producer of engineered glass products used in transportation safety, metal finishing and polymer additives. The Acquisition was accounted for using the acquisition method of accounting. Under the acquisition method, the purchase price was allocated to the identifiable net assets acquired based on the fair values of the identifiable assets acquired and liabilities assumed as of the Closing Date. The excess of the purchase price over the fair values of the identifiable net assets acquired was recorded to goodwill. The following table sets forth the calculation and preliminary allocation of the purchase price to the identifiable net assets acquired with respect to the Acquisition: Total consideration, net of cash acquired $ 41,572 Recognized amounts of identifiable assets acquired and liabilities assumed: Receivables $ 14,305 Inventories 7,645 Prepaid and other current assets 230 Property, plant and equipment 9,020 Other long-term assets 129 Fair value of assets acquired 31,329 Current debt (6,420 ) Accounts payable (10,748 ) Long-term debt (10,189 ) Other long-term liabilities (154 ) Fair value of net assets acquired 3,818 Goodwill 37,754 $ 41,572 The valuation of the identifiable assets and liabilities included in the table above is preliminary and is subject to change, as the Company is in the process of evaluating the information required to determine the fair values of certain identifiable assets and liabilities acquired, including inventory, property, plant and equipment, and intangible assets. An increased portion of the purchase price allocated to the identifiable net assets acquired will reduce the amount recognized for goodwill and may result in increased cost of goods sold, depreciation and/or amortization expense. Adjustments to the provisional amounts during the measurement period that result in changes to depreciation, amortization or other income effects will be recognized in the reporting period(s) in which the adjustments are determined. The Company’s condensed consolidated financial statements include Sovitec’s results of operations for the period from the Closing Date through September 30, 2017 . Net sales and net income attributable to Sovitec during this period are included in the Company’s condensed consolidated statement of operations and total $13,490 and $644 , respectively, for the three months ended September 30, 2017 , and $17,194 and $1,148 , respectively, for the nine months ended September 30, 2017 . Acquisition costs of $737 and $2,065 are included in other operating expense, net in the Company’s condensed consolidated statement of operations for the three and nine months ended September 30, 2017 , respectively. The Company believes that the Acquisition will enable it to offer a more comprehensive, cost-effective and high-quality portfolio of products and services to its customers worldwide when, combined with anticipated synergies within its existing business, contributed to a total purchase price that resulted in the recognition of goodwill. All of the goodwill was assigned to the Company’s Performance Materials and Chemicals segment. The goodwill associated with the Acquisition is not deductible for tax purposes. Pro Forma Financial Information The unaudited pro forma financial information for the three months ended September 30, 2016 and the nine months ended September 30, 2017 and 2016 has been derived from the Company’s historical consolidated financial statements and prepared to give effect to the Acquisition, assuming that the Acquisition occurred on January 1, 2016. The unaudited pro forma consolidated results of operations are provided for illustrative purposes only and are not indicative of the Company’s actual consolidated results of operations had the Acquisition been made as of January 1, 2016. The unaudited pro forma results of operations do not reflect any operating efficiencies or potential cost savings which may result from the Acquisition. The results of operations for the three months ended September 30, 2017 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Three months ended September 30, Nine months ended 2016 2017 2016 (unaudited) Pro forma sales $ 381,065 $ 1,130,454 $ 772,549 Pro forma net loss (8,289 ) (6,511 ) (88,300 ) Certain non-recurring charges included in the Company’s results of operations for the nine months ended September 30, 2017 were allocated to the respective prior year periods for pro forma purposes. For the nine months ended September 30, 2017 , non-recurring charges allocated to the prior year period include transaction fee charges of $2,065 which were excluded from the pro forma net loss for the nine months ended September 30, 2017 . Business Combination: As described in Note 1 to these condensed consolidated financial statements, on May 4, 2016, the Company, PQ Holdings, Eco Services, certain investment funds affiliated with CCMP and certain other stockholders of PQ Holdings and Eco Services completed the Business Combination. Eco Services is the accounting predecessor to PQ Group Holdings. Certain investment funds affiliated with CCMP held a controlling interest position in Eco Services prior to the Business Combination. In addition, certain investment funds affiliated with CCMP owned a noncontrolling interest in PQ Holdings prior to the Business Combination and the merger with Eco constituted a change in control under the various PQ Holdings credit agreements and bond indenture. Therefore, Eco Services is deemed to be the accounting acquirer. These condensed consolidated financial statements are the continuation of Eco Services’ business prior to the Business Combination. Total consideration for the Business Combination included $1,777,740 of cash, $910,800 of equity in the acquired PQ Holdings entities and $1,401 of assumed stock awards of PQ Holdings. The fair value of the equity consideration was determined based on an estimated enterprise value using a market approach as of the date of the Business Combination, reduced by borrowings to arrive at the fair value of equity. The existing PQ Holdings credit facilities were not legally assumed as part of the Business Combination and the extinguishment of the debt concurrent with the Business Combination was included as part of the consideration transferred. The Company’s condensed consolidated financial statements include PQ Holdings results of operations from May 4, 2016 through September 30, 2016 . Net sales and net loss attributable to PQ Holdings during this period are included in the Company’s condensed consolidated statement of operations and total $276,726 and $29,070 for the three months ended September 30, 2016 and $462,097 and $122,497 for the nine months ended September 30, 2016 . Acquisition costs of $896 and $1,398 are included in other operating expense, net in the Company’s consolidated statement of operations for the three and nine months ended September 30, 2016 , respectively. In accordance with the requirements of the purchase method of accounting for acquisitions, inventories were recorded at fair market value (which is defined as estimated selling prices less the sum of (a) costs of disposal and (b) a reasonable profit allowance for the selling effort of the acquiring entity), which was $58,683 higher than the historical cost. The Company’s cost of goods sold includes a pre-tax charge of $5,804 and $23,518 for the three and nine months ended September 30, 2016 , respectively, relating to the portion of the step-up on inventory sold during the period. A separate portion of the fair value step-up related to the domestic inventory accounted for under the LIFO method was included in inventory on the consolidated balance sheet as of December 31, 2016 as part of the new LIFO base layer on the acquired inventory. Pro Forma Financial Information The unaudited pro forma financial information for the nine months ended September 30, 2016 has been derived from the Company’s historical consolidated financial statements and prepared to give effect to the Business Combination, assuming that the Business Combination occurred on January 1, 2015. These pro forma adjustments primarily relate to incremental depreciation expense on the step up of fixed assets, amortization of acquired intangibles, higher cost of goods sold related to the sale of revalued inventory, incremental interest expense related to the additional debt that needed to fund the Business Combination, and the estimated impact of these adjustments on the Company’s tax provision. The unaudited pro forma consolidated results of operations are provided for illustrative purposes only and are not indicative of the Company’s actual consolidated results of operations had the Business Combination been made as of January 1, 2015. The unaudited pro forma results of operations do not reflect any operating efficiencies or potential cost savings which may result from the Business Combination. The results of operations for the three months ended September 30, 2016 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Nine months ended September 30, 2016 (unaudited) Pro forma sales $ 1,080,310 Pro forma net loss (55,985 ) Certain non-recurring charges included in the Company’s results of operations for the nine months ended September 30, 2016 were allocated to the respective prior year periods for pro forma purposes. For the nine months ended September 30, 2016 , non-recurring charges allocated to the prior year period include a debt prepayment penalty of $26,250 , refinancing charges of $4,616 and transaction fee charges of $714 , all of which are excluded from the pro forma net loss for the nine months ended September 30, 2016 .

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The changes in the carrying amount of goodwill for the nine months ended September 30, 2017 is summarized as follows: Performance Environmental Total Balance as of December 31, 2016 $ 852,506 $ 388,923 $ 1,241,429 Goodwill recognized 37,754 — 37,754 Foreign exchange impact 25,189 2,175 27,364 Balance as of September 30, 2017 $ 915,449 $ 391,098 $ 1,306,547

Other Operating Expense, Net

Other Operating Expense, Net	9 Months Ended
	Sep. 30, 2017
Other Income and Expenses [Abstract]
Other Operating Expense, Net	Other Operating Expense, Net: A summary of other operating expense, net is as follows: Three months ended Nine months ended 2017 2016 2017 2016 Restructuring and other related costs (Note 18) $ 4,106 $ 1,336 $ 5,578 $ 10,898 Amortization expense 9,146 8,914 23,270 17,029 Net loss on asset disposals 3,494 627 6,419 2,288 Transaction and other related costs (1) 966 1,635 5,295 6,063 Management advisory fees 1,250 1,250 3,750 2,333 Other, net 871 1,280 2,844 2,019 $ 19,833 $ 15,042 $ 47,156 $ 40,630 ————— (1) Transaction and other related costs primarily include acquisition costs directly attributable to the Acquisition (see Note 5 to these condensed consolidated financial statements for further information) and the Business Combination (see Note 6 to these condensed consolidated financial statements for further information), as well as other business development costs.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2017
Inventory Disclosure [Abstract]
Inventories	Inventories: Inventories are classified and valued as follows: September 30, 2017 December 31, 2016 Finished products and work in process $ 178,844 $ 175,182 Raw materials 57,077 51,866 $ 235,921 $ 227,048 Valued at lower of cost or market: LIFO basis $ 145,905 $ 135,605 FIFO or average cost basis 90,016 91,443 $ 235,921 $ 227,048

Investments in Affiliated Compa

Investments in Affiliated Companies	9 Months Ended
	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Investments in Affiliated Companies	Investments in Affiliated Companies: The Company accounts for investments in affiliated companies under the equity method. Affiliated companies accounted for on the equity basis as of September 30, 2017 are as follows: Company Country Percent PQ Silicates Ltd. Taiwan 50% Zeolyst International USA 50% Zeolyst C.V. Netherlands 50% Quaker Holdings South Africa 49% Following is summarized information of the combined investments: Three months ended Nine months ended 2017 2016 2017 2016 Net sales $ 83,983 $ 63,110 $ 225,770 $ 107,897 Gross profit 33,276 24,283 91,862 46,589 Operating income 22,713 15,054 60,408 30,708 Net income 23,819 15,351 63,663 30,994 The Company’s investments in affiliated companies balance as of September 30, 2017 and December 31, 2016 includes net purchase accounting fair value adjustments of $ 266,358 and $ 273,300 , respectively, related to the Business Combination, consisting primarily of goodwill and intangible assets such as customer relationships, technical know-how and trade names. Consolidated equity in net income from affiliates is net of $ 1,660 and $6,942 of amortization expense related to purchase accounting fair value adjustments for the three and nine months ended September 30, 2017 , respectively. Consolidated equity in net income from affiliates is net of $12,291 and $24,606 of amortization expense related to purchase accounting fair value adjustments for the three and nine months ended September 30, 2016 , respectively.

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment: A summary of property, plant and equipment, at cost, and related accumulated depreciation is as follows: September 30, 2017 December 31, 2016 Land $ 191,917 $ 186,327 Buildings 191,916 157,944 Machinery and equipment 955,779 788,175 Construction in progress 155,005 204,138 1,494,617 1,336,584 Less: accumulated depreciation (285,570 ) (155,196 ) $ 1,209,047 $ 1,181,388 Depreciation expense was $ 31,957 and $ 30,305 for the three months ended September 30, 2017 and 2016 , respectively. Depreciation expense was $89,987 and $60,173 for the nine months ended September 30, 2017 and 2016 , respectively.

Long-term Debt

Long-term Debt	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt: The summary of long-term debt is as follows: September 30, 2017 December 31, 2016 Term Loan Facility (U.S. dollar denominated) $ 918,473 $ 925,430 Term Loan Facility (Euro denominated) 331,368 297,317 6.75% Senior Secured Notes due 2022 625,000 625,000 Floating Rate Senior Unsecured Notes due 2022 525,000 525,000 8.5% Senior Notes due 2022 200,000 200,000 ABL Facility 35,000 — Other 68,207 45,223 Total debt 2,703,048 2,617,970 Original issue discount (26,470 ) (28,497 ) Deferred financing costs (24,842 ) (27,275 ) Total debt, net of original issue discount and deferred financing costs 2,651,736 2,562,198 Less: current portion (54,255 ) (14,481 ) Total long-term debt $ 2,597,481 $ 2,547,717 The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction. As of September 30, 2017 and December 31, 2016 , the fair value of the senior secured term loans and senior secured and unsecured notes was higher than book value by $ 69,936 and $ 68,477 , respectively. The fair value of the senior secured term loans and senior secured and unsecured notes was derived from published loan prices as of September 30, 2017 and December 31, 2016 , as applicable. The fair value is classified as Level 2 based upon the fair value hierarchy (see Note 3 to these condensed consolidated financial statements for further information on fair value measurements). New Markets Tax Credit Financing On June 22, 2017, the Company’s subsidiary, Potters Industries, LLC (“Potters”), entered into a New Markets Tax Credit (“NMTC”) financing arrangement with U.S. Bank N.A. (“USB”), one of USB’s affiliates (“USB Investment Fund”) and Business Conduit No. 28, LLC, an affiliate of Community Reinvestment Fund, Inc. (“CRF”). USB contributed $3,054 to USB Investment Fund, and Potters Leveraged Lender LLC, an indirect subsidiary of the Company, lent USB Investment Fund $6,221 . USB Investment Fund then contributed $9,000 to CRF, which in turn lent $8,820 to Potters pursuant to a credit agreement (the “June 2017 NMTC Agreement”). Potters used the $8,820 in proceeds to acquire equipment for the expansion of Potters’ manufacturing facility in Paris, Texas. The June 2017 NMTC Agreement provides the Company with certain monetary benefits as an offset to specifically identified capital expenditures. The June 2017 NMTC Agreement requires that certain commitments and covenants are maintained over a period of seven years in order to legally recognize the benefit. The $8,820 was outstanding as of September 30, 2017 . The capital expenditures associated with the June 2017 NMTC Agreement are expected to be completed in 2017. In connection with the June 2017 NMTC Agreement, the Company provided an indemnification related to its actions or inactions which cause either a NMTC disallowance or recapture event. In the event that the Company causes either a recapture or disallowance of the tax credits expected to be generated under this program, then the Company will be required to repay the disallowed or recaptured tax credits plus an amount sufficient to pay the taxes on such repayment to the counterparty of the agreement. This indemnification covers the Company’s actions and inactions prior to June 22, 2024. The maximum potential amount of future payments under this indemnification is approximately $3,682 . The Company currently believes that the likelihood of a required payment under this indemnification is remote. Term Loans Repricing On August 7, 2017, the Company re-priced the existing $927,750 U.S. dollar-denominated tranche and the existing €283,338 Euro-denominated tranche of its term loans to reduce the applicable interest rates. The terms of the facilities are substantially consistent following the re-pricing, except that borrowings under the term loans bear interest at a rate equal to the LIBOR rate plus a margin of 3.25% with respect to U.S. dollar-denominated LIBOR rate loans, and the EURIBOR rate plus a margin of 3.25% with respect to Euro-denominated EURIBOR rate loans. In addition, the LIBOR rate elected under the facilities is subject to a floor of 0% and the EURIBOR rate elected under the facilities is subject to a floor of 0.75% . Senior Unsecured Notes Partial Repayment Subsequent to September 30, 2017 and in conjunction with the Company’s IPO, on October 3, 2017, the Company repaid $446,208 , in aggregate principal of the $525,000 of PQ Corporation’s Floating Rate Senior Unsecured Notes due 2022 using the proceeds from the IPO. In connection with the repayment, the Company also paid accrued interest of $2,693 and applicable redemption premiums of $32,284 .

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments: The Company uses interest rate related derivative instruments to manage its exposure related to changes in interest rates on its variable-rate debt instruments and uses commodity derivatives to manage its exposure to commodity price fluctuations. The Company does not speculate using derivative instruments. By using derivative financial instruments to hedge exposures to changes in interest rates and commodity prices, the Company exposes itself to credit risk and market risk. Credit risk is the failure of the counterparty to perform under the terms of the derivative contract. When the fair value of a derivative contract is an asset, the counterparty owes the Company, which creates credit risk for the Company. When the fair value of a derivative contract is a liability, the Company owes the counterparty and, therefore, the Company is not exposed to the counterparty’s credit risk in those circumstances. The Company minimizes counterparty credit risk in derivative instruments by entering into transactions with high quality counterparties. The derivative instruments entered into by the Company do not contain credit-risk-related contingent features. Market risk is the adverse effect on the value of a derivative instrument that results from a change in interest rates, currency exchange rates, or commodity prices. The market risk associated with interest rate and commodity price contracts is managed by establishing and monitoring parameters that limit the types and degree of market risk that may be undertaken. Use of Derivative Financial Instruments to Manage Commodity Price Risk. The Company is exposed to risks in energy costs due to fluctuations in energy prices, particularly natural gas. The Company has a hedging program in the United States which allows the Company to mitigate exposure to natural gas volatility with natural gas swap agreements. Fair value is determined based on estimated amounts that would be received or paid to terminate the contracts at the reporting date based on quoted market prices of comparable contracts. The respective current and non-current liabilities are recorded in accrued liabilities and other long-term liabilities and the respective current and non-current assets are recorded in prepaid and other current assets and other long-term assets, as applicable. As the derivatives are highly effective and are designated and qualify as cash-flow hedges, the related unrealized gains or losses are recorded in stockholders’ equity as a component of other comprehensive income (loss), net of tax. Realized gains and losses on natural gas hedges are included in production cost and subsequently charged to cost of goods sold in the consolidated statements of operations in the period in which inventory is sold. The Company’s natural gas swaps have a remaining notional quantity of 690,000 MMBTU to mitigate commodity price volatility through December 2018. Use of Derivative Financial Instruments to Manage Interest Rate Risk. The Company is exposed to fluctuations in interest rates on its senior secured credit facilities and senior unsecured notes. Changes in interest rates will not affect the market value of such debt but will affect the amount of our interest payments over the term of the loans. Likewise, an increase in interest rates could have a material impact on the Company’s cash flow. The Company hedges the interest rate fluctuations on debt obligations through interest rate cap agreements. The Company records these agreements at fair value as assets or liabilities. As the derivatives are highly effective and are designated and qualify as cash-flow hedges, the related unrealized gains or losses are deferred in stockholders’ equity as a component of other comprehensive income (loss), net of tax. Fair value is determined based on estimated amounts that would be received or paid to terminate the contracts at the reporting date based on quoted market prices. In July 2016, the Company entered into interest rate cap agreements, paying a premium of $1,551 to mitigate interest rate volatility from July 2016 through July 2020 by employing varying cap rates, ranging from 1.50% to 3.00% on $1,000,000 of notional variable-rate debt. The fair values of derivative instruments held as of September 30, 2017 and December 31, 2016 are shown below: Balance sheet location September 30, 2017 December 31, 2016 Asset derivatives: Derivatives designated as cash flow hedges: Natural gas swaps Current assets $ — $ 573 Interest rate caps Current assets 9 — Natural gas swaps Other long-term assets 7 58 Interest rate caps Other long-term assets 1,082 5,803 Total asset derivatives $ 1,098 $ 6,434 Liability derivatives: Derivatives designated as cash flow hedges: Natural gas swaps Accrued liabilities $ 58 $ — Total liability derivatives $ 58 $ — The following tables show the effect of the Company’s derivative instruments designated as hedges on other comprehensive income (loss) (“OCI”) and the statement of income for the three and nine months ended September 30, 2017 and 2016 : Three months ended September 30, 2017 2016 Derivatives designated as cash flow hedges: Location in Earnings Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Interest rate caps Interest expense $ (1,842 ) $ 13 $ 212 $ (2 ) Natural gas swaps Cost of goods sold (28) 94 (306) 420 $ (1,870 ) $ 107 $ (94 ) $ 418 Nine months ended September 30, 2017 2016 Derivatives designated as cash flow hedges: Location in Earnings Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Interest rate caps Interest expense $ (4,712 ) $ 22 $ 212 $ (2 ) Natural gas swaps Cost of goods sold (787) 104 (1,723) 1,148 $ (5,499 ) $ 126 $ (1,511 ) $ 1,146 Amounts of unrealized losses in OCI that are expected to be reclassified to the consolidated statement of operations over the next twelve months are $ 241 as of September 30, 2017 .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes: The effective income tax rate for the three months ended September 30, 2017 was 239.9% compared to 26.9% for the three months ended September 30, 2016 . The effective income tax rate for the nine months ended September 30, 2017 was (304.2)% compared to (67.1)% for the nine months ended September 30, 2016 . The Company’s effective income tax rate fluctuates based primarily on changes in income mix, repatriation of income taxes from foreign subsidiaries and, for the comparative periods, the change in Eco Services’ tax status. Prior to the Business Combination on May 4, 2016, Eco Services was a single member limited liability company and taxed as a partnership for federal and state income tax purposes. As such, all income tax liabilities and/or benefits of Eco Services were passed through to its members. Because Eco Services was taxed as a partnership, it did not record deferred taxes on the basis difference on its financial statements. Following the Business Combination on May 4, 2016, Eco Services had a change in tax status and is now taxed as a C-Corporation subject to federal and state corporate level income taxes at prevailing corporate rates. Minimal taxes were recorded on the book losses incurred by Eco Services during the periods preceding the Business Combination included in the nine months ended September 30, 2016 , causing the fluctuation to the Company’s effective income tax rate in comparison to the taxes recorded for the nine months ended September 30, 2016 . The difference between the U.S. federal statutory income tax rate and the Company’s effective income tax rate for 2017 was mainly due to the tax effect of the Company’s foreign currency exchange loss recognized as a discrete item for the purpose of calculating the effective tax rate as well as the tax effect of repatriating foreign earnings back to the U.S. as dividends, partially offset by lower tax rates in foreign jurisdictions as compared to the U.S. federal tax rate, foreign withholding taxes, state taxes and non-deductible transaction costs.

Benefit Plans

Benefit Plans	9 Months Ended
	Sep. 30, 2017
Retirement Benefits [Abstract]
Benefit Plans	Benefit Plans: The following information is provided for (1) the Company-sponsored defined benefit pension plans covering employees in the U.S. and certain employees at its foreign subsidiaries, (2) the Company-sponsored unfunded plans to provide certain health care benefits to retired employees in the U.S. and Canada, and (3) the Company’s defined benefit supplementary retirement plans which provide benefits for certain U.S. employees in excess of qualified plan limitations. Components of net periodic expense are as follows: Defined Benefit Pension Plans U.S. Foreign Three months ended Three months ended 2017 2016 2017 2016 Service cost $ 305 $ 547 $ 859 $ 792 Interest cost 2,536 2,522 1,339 837 Expected return on plan assets (3,061 ) (3,104 ) (1,111 ) (769 ) Net periodic expense (benefit) $ (220 ) $ (35 ) $ 1,087 $ 860 U.S. Foreign Nine months ended Nine months ended 2017 2016 2017 2016 Service cost $ 914 $ 1,640 $ 2,642 $ 1,320 Interest cost 7,608 5,236 4,024 1,396 Expected return on plan assets (9,183 ) (6,176 ) (3,329 ) (1,283 ) Net periodic expense (benefit) $ (661 ) $ 700 $ 3,337 $ 1,433 Supplemental Retirement Plans Three months ended Nine months ended 2017 2016 2017 2016 Interest cost $ 123 $ 121 $ 370 $ 202 Net periodic expense $ 123 $ 121 $ 370 $ 202 Other Postretirement Benefit Plans Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 Service cost $ 5 $ 9 $ 15 $ 28 Interest cost 40 53 122 110 Amortization of prior service credit (19 ) — (58 ) — Amortization of net gain (19 ) — (58 ) — Net periodic expense $ 7 $ 62 $ 21 $ 138

Commitments and Contingent Liab

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Commitments and Contingent Liabilities: There is a risk of environmental impact in chemical manufacturing operations. The Company’s environmental policies and practices are designed to ensure compliance with existing laws and regulations and to minimize the possibility of significant environmental impact. The Company is also subject to various other lawsuits and claims with respect to matters such as governmental regulations, labor and other actions arising out of the normal course of business. No accrual for these matters currently exists, with the exception of those listed below, because management believes that the liabilities resulting from such lawsuits and claims are not probable or reasonably estimable. The Company triggered the requirement of New Jersey’s Industrial Site Recovery Act (“ISRA”) statute with the PQ Holdings stock transfer/corporate merger in December 2004. As required under ISRA, a General Information Notice with respect to the Company’s two New Jersey locations was filed with the New Jersey Department of Environmental Protection (“NJDEP”) in December 2004 and again in July 2007. Based on an initial review of the facilities by the NJDEP in 2005, the Company estimated that $500 would be required for contamination assessment and removal work of one specific contaminant (polychlorinated biphenyls) that exceeded applicable NJDEP standards at these facilities, and had recorded a reserve for such amount as of December 31, 2005. During subsequent years, it was determined that additional assessment, removal and remediation work would be required and the reserve was increased to cover the estimated cost of such work. In addition, during this period, work had been performed and the reserve was reduced for actual costs incurred for the assessment and remediation work. Work at the Carlstadt facility has been completed and is closed from an ISRA standpoint, but as of September 30, 2017 and December 31, 2016 , the Company has recorded a reserve of $ 557 and $ 700 , respectively, for costs required for contamination assessment and removal work at Rahway. There may be additional costs related to the remediation of Rahway, but until further investigation takes place, the Company cannot reasonably estimate the amount of additional liability that may exist. As part of a Delaware River Basin Commission (“DRBC”) required Pollutant Minimization Plan (“PMP”), in July 2013, the Company’s Chester facility conducted limited paint sampling for polychlorinated biphenyls (“PCBs”). Also, as part of demolition, repair and maintenance projects scheduled for the Company’s Baltimore facility in 2014, the Company conducted limited paint sampling during the fall of 2013 for waste categorization purposes. Paint samples were analyzed for PCB Aroclor 1254, the specific PCB congener commonly used in the manufacture of paint until the late 1970s. The Company’s analytical results indicated that PCB Aroclor 1254 is present in paint on some structures (e.g., piping, structural steel, tanks) in excess of the fifty (50) parts per million (“ppm”) regulatory threshold. Under the Toxic Substances Control Act (“TSCA”), there is no requirement to test in use paint for PCB content. However, once PCB content is identified at concentrations at or above the regulatory threshold, absent specific approval from the U.S. Environmental Protection Agency (“EPA”), the PCB-containing paint is regulated as an unauthorized use of PCBs, and the paint must be addressed. The Company abated painted surfaces that have tested positive for PCBs at levels exceeding 50 ppm at Baltimore in 2015 and early 2016. Similar abatement of painted structures as necessary at Chester have also been substantially completed. Characterization studies to evaluate whether soils have been impacted at Baltimore have been initiated as required under the TSCA, and have yet to commence at Chester. As of September 30, 2017 and December 31, 2016 , the Company has recorded a reserve of $ 236 and $ 1,048 , respectively, for the remediation costs of PCB impacted soils at the Company’s facilities. In 2011, the Company installed a Continuous Emissions Monitor (“CEM”) to measure CO, NOx and Opacity emissions from a furnace at the Company’s Chester facility in Pennsylvania, and the Company conducted Relative Accuracy Test Audits (“RATA”) as part of its efforts to certify the CEM. On May 5, 2014, the Pennsylvania Department of Environmental Protection (“PADEP”) officially notified the Company that it was certifying the CEM based on RATA test results dating back to November 2011 and instructed the Company to start entering data previously recorded by the CEM into the Agency’s on-line database. During the third and fourth quarters of 2014, the Company officially entered data recorded from the CEM up until the second quarter of 2013. In November 2015, PADEP issued an Assessment of Civil Penalty in the amount of $1,739 for alleged violations under the Pennsylvania Air Pollution Control Act during the period from August 11, 2011 through June 30, 2013. The Company appealed, and PADEP reduced the penalty assessment to $1,550 . After a hearing on the appeal, a Pennsylvania Environmental Hearing Board (“EHB”) judge reduced the penalty assessment to $215 in September 2017. The PADEP filed a motion to reconsider a portion of the EHB judge’s decision and the EHB denied the PADEP’s motion in October 2017. As of September 30, 2017 and December 31, 2016 , the Company has recorded a reserve of $ 215 and $1,500 , respectively, associated with the PADEP penalty. The Company has a manufacturing facility at Warrington, United Kingdom. Asbestos-containing building material is present at the site, and asbestos removal and insulation replacement initiatives are underway. As of September 30, 2017 and December 31, 2016 , the Company has recorded a reserve of $ 573 and $ 532 , respectively, for costs related to this program. In 2008, the Company sold the property of a manufacturing facility located in the United States to the local port authority. In 2009, the port authority commissioned an environmental investigation of portions of the property. In 2010, the port authority advised the Company of alleged soil and groundwater contamination on the property and alleged the Company liable for certain conditions. The Company received and reviewed the environmental investigation documentation and determined it may have liability with respect to some, but not all, of the alleged contamination. As of September 30, 2017 and December 31, 2016 , the Company has recorded a reserve of $ 839 and $ 913 , respectively, for costs related to this potential liability. The Company has recorded a reserve of $ 1,380 and $ 1,776 as of September 30, 2017 and December 31, 2016 , respectively, to address remaining subsurface remedial and wetlands/marsh management activities at the Company’s Martinez, CA site. Although currently a sulfuric acid regeneration plant, the site originally was operated by Mountain Copper Company (“Mococo”) as a copper smelter. Also, the site sold iron pyrite to various customers and allowed their customers to deposit waste iron pyrite cinder and slag on the site. The property is adjacent to Peyton Slough, where Mococo had a permitted discharge point from its process. In 1997, the San Francisco Bay Regional Water Quality Control Board (“RWQCB”) required characterization and remediation of Peyton Slough for Copper, Zinc and Acidic Soils. Various remediation activities were undertaken and completed, and the site has received final concurrence from the Army Corps with respect to the completed work. The RWQCB has agreed that Eco Services has achieved the goals for vegetative cover, but the current marsh condition is not sustainable without continued operation of the tide gates. The Company is continuing to work with the RWQCB on a plan to involve the County and work towards development of an alliance for operating, maintaining and funding the tide gates in the future. As of September 30, 2017 and December 31, 2016 , the Company has recorded a reserve of $ 1,444 and $ 1,755 , respectively, for subsurface remediation and the Soil Vapor Extraction Project at the Company’s Dominguez, CA site. In the 1980s and 1990s, the EPA and the Los Angeles Regional Water Quality Control Board conducted investigations of the site due to historic chlorinated pesticide and chlorinated solvent use. Soil and groundwater beneath the site were impacted by chlorinated solvents and associated breakdown products, petroleum hydrocarbons, chlorinated pesticides and metals. A Corrective Measures Plan approved in October 2011 requires (1) soil vapor extraction (“SVE”) in affected areas, (2) covering of unpaved areas containing pesticide impacted soil, and (3) annual groundwater monitoring of the perched water-bearing zone. Installation of the SVE unit has been completed and startup has occurred. The California Department of Toxic Substances Control (“DTSC”) has granted conditional approval of the Company’s soil management, and monitoring and maintenance plans. Most recently, the DTSC is requiring the Company to delineate the PCE plume on the eastern boundary of the site. The Company has submitted an action plan to address this matter and is awaiting comments from the DTSC.

Reportable Segments

Reportable Segments	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Reportable Segments	Reportable Segments: Summarized financial information for the Company’s (1) Performance Materials & Chemicals and (2) Environmental Catalysts & Services reportable segments is shown in the following table: Three months ended Nine months ended 2017 2016 2017 2016 Net sales: Performance Materials & Chemicals $ 277,072 $ 256,219 $ 765,781 $ 429,867 Environmental Catalysts & Services (1) 115,541 114,271 350,814 312,490 Eliminations (2) (784 ) (511 ) (2,568 ) (911 ) Total $ 391,829 $ 369,979 $ 1,114,027 $ 741,446 Segment Adjusted EBITDA: (3) Performance Materials & Chemicals $ 65,885 $ 64,604 $ 184,741 $ 111,178 Environmental Catalysts & Services (4) 61,900 56,341 182,578 135,044 Total Segment Adjusted EBITDA (5) $ 127,785 $ 120,945 $ 367,319 $ 246,222 ————— (1) Excludes the Company’s proportionate share of sales from the Zeolyst International and Zeolyst C.V. joint ventures (collectively, the “Zeolyst Joint Venture”) accounted for using the equity method (see Note 10 to these condensed consolidated financial statements for further information). The proportionate share of sales is $37,622 and $28,184 for the three months ended September 30, 2017 and 2016 , respectively. The proportionate share of sales is $100,991 and $48,461 for the nine months ended September 30, 2017 and 2016 , respectively. (2) The Company eliminates intersegment sales when reconciling to the Company’s consolidated statements of operations. (3) The Company defines Adjusted EBITDA as EBITDA adjusted for certain items as noted in the reconciliation below. Management evaluates the performance of its segments and allocates resources based on several factors, of which the primary measure is Adjusted EBITDA. Adjusted EBITDA should not be considered as an alternative to net income as an indicator of the Company’s operating performance. Adjusted EBITDA as defined by the Company may not be comparable with EBITDA or Adjusted EBITDA as defined by other companies. (4) The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $14,398 for the three months ended September 30, 2017, which includes $10,151 of equity in net income plus $1,658 of amortization of investment in affiliate step-up plus $2,563 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $10,316 for the three months ended September 30, 2016, which includes $4,683 of equity in net loss plus $12,291 of amortization of investment in affiliate step-up plus $2,690 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $39,690 for the nine months ended September 30, 2017, which includes $24,594 of equity in net income plus $6,941 of amortization of investment in affiliate step-up plus $8,073 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $19,962 for the nine months ended September 30, 2016, which includes $9,213 of equity in net loss plus $24,606 of amortization of investment in affiliate step-up plus $4,534 of joint venture depreciation, amortization and interest. (5) Total Segment Adjusted EBITDA differs from the Company’s consolidated Adjusted EBITDA due to unallocated corporate expenses. A reconciliation from net loss to Segment Adjusted EBITDA is as follows: Three months ended Nine months ended 2017 2016 2017 2016 Reconciliation of net loss attributable to PQ Group Holdings Inc. to Segment Adjusted EBITDA Net loss attributable to PQ Group Holdings Inc. $ (3,345 ) $ (10,017 ) $ (7,408 ) $ (90,410 ) Provision for (benefit from) income taxes 5,172 (3,536 ) 5,269 36,013 Interest expense, net 49,079 48,610 144,041 94,362 Depreciation and amortization 45,929 43,611 129,135 85,602 Segment EBITDA 96,835 78,668 271,037 125,567 Unallocated corporate expenses 7,885 7,316 23,474 13,940 Joint venture depreciation, amortization and interest 2,563 2,690 8,073 4,534 Amortization of investment in affiliate step-up 1,660 12,291 6,942 24,606 Amortization of inventory step-up — 5,804 871 23,518 Debt extinguishment costs 453 — 453 11,858 Losses on disposal of fixed assets 3,494 627 6,419 2,288 Foreign currency exchange losses 5,256 3,151 21,612 6,240 Non-cash revaluation of inventory, including LIFO 750 329 3,229 775 Management advisory fees 1,250 1,250 3,750 2,333 Transaction and other related costs 966 1,696 5,300 6,240 Equity-based and other non-cash compensation 1,041 1,137 3,869 4,916 Restructuring, integration and business optimization expenses 4,957 2,839 8,009 14,567 Defined benefit pension plan cost 791 1,244 2,200 2,642 Other (116 ) 1,903 2,081 2,198 Segment Adjusted EBITDA $ 127,785 $ 120,945 $ 367,319 $ 246,222

Restructuring and Other Related

Restructuring and Other Related Costs	9 Months Ended
	Sep. 30, 2017
Restructuring and Related Activities [Abstract]
Restructuring and Other Related Costs	Restructuring and Other Related Costs: The following table presents the components of restructuring and other related costs for the three and nine months ended September 30, 2017 and 2016 : Three months ended Nine months ended 2017 2016 2017 2016 Severance and other employee costs related to legacy Eco restructuring plan $ — $ — $ 830 $ 4,496 Severance and other employee costs related to performance materials plant closure 3,868 — 3,868 — Other related costs 238 1,336 880 6,402 $ 4,106 $ 1,336 $ 5,578 $ 10,898 Legacy Eco Restructuring Plan On July 30, 2014, Eco Services, a newly formed Delaware limited liability company and indirect subsidiary of certain investment funds affiliated with CCMP, entered into an Asset Purchase Agreement with Solvay USA, Inc. (“Solvay”), a Delaware corporation, which provided for the sale, transfer and assignment by Solvay and the acquisition, acceptance and assumption by Eco Services, of substantially all of the assets of Solvay’s Eco Services business unit of Solvay’s regeneration and virgin sulfuric acid production business operations in the United States (the “2014 Acquisition”). Prior to the Asset Purchase Agreement with Solvay, Eco Services operated as a business unit within Solvay, which is an indirect, wholly owned subsidiary of Solvay SA. Subsequent to the 2014 Acquisition, the Company initiated a restructuring plan designed to improve organizational efficiency and streamline the operations of Eco Services as a stand-alone company. The primary impact of the plan to the Company’s consolidated results of operations was the recognition of severance costs related to a reduction-in-force. These costs included benefits payable under ongoing Company severance plan arrangements, whereby payments are attributable to employee services rendered with benefits that accumulate over time. The liabilities and associated charges related to these severance costs are recognized by the Company when payment of the benefits becomes probable and estimable. Charges related to severance costs for the restructuring plan were $830 and $4,496 for the nine months ended September 30, 2017 and 2016 , respectively. No severance costs were incurred related to this plan for the three months ended September 31, 2017 and 2016. Performance Materials Plant Closure In September 2017, the Company approved and announced a plan to consolidate its manufacturing operations in Europe for the performance materials product group and close its facility in Kirchheimbolanden, Germany. The plan is part of the Company’s overall strategy with respect to the Sovitec acquisition (see Note 5 to these condensed consolidated financial statements) and the realization of cost and other synergies related to the business combination. The facility will remain in operation over the short term in a reduced capacity, and the Company plans to cease operations at the location on or about March 31, 2018. The Company plans to relocate the manufacturing equipment to other European facilities, and is exploring strategic alternatives for the building and land. As a result, the Company classified the plant under the “held and used” accounting model as of September 30, 2017, as it did not meet the criteria to be classified as “held for sale.” As a result of the decision and announcement regarding the plant, the Company performed an impairment assessment related to the fixed assets of the facility. In conducting the recoverability assessment, the Company compared the carrying value of the asset group that includes the plant to the undiscounted future cash flows of the asset group, noting that there was no indication of impairment. The Company does not anticipate the acceleration of depreciation on the fixed assets associated with the plant, as the Company continues to utilize the assets and ultimately expects to relocate the equipment. In addition to the fixed asset recoverability evaluation, the Company recorded a severance charge related to the pending closure and other cost reductions for its performance materials product group in Europe of $3,868 for the three months ended September 30, 2017. The charge was fully recognized as of September 30, 2017 based on the types of benefits provided and the criteria for restructuring and exit cost recognition. Although the Company does not expect to incur additional severance costs related to the closure, the Company will incur additional costs related to the dismantling, transportation and reassembly of the manufacturing equipment after the plant ceases operations, which is currently estimated to be between $500 and $1,000 . Rollforward of Restructuring Liabilities The activity in the accrued liability balance associated with the Company’s restructuring plans, all of which related to severance and other employee costs, was as follows for the nine months ended September 30, 2017 : Legacy Eco Restructuring Plan Performance Materials Plant Closure Total Restructuring Charges Balance at December 31, 2016 $ 1,643 $ — $ 1,643 Restructuring charges 830 3,868 4,698 Cash payments (1,971 ) — (1,971 ) Balance at September 30, 2017 $ 502 $ 3,868 $ 4,370 The remaining accrued liability balance associated with the restructuring plans at September 30, 2017 is expected to be paid in 2018. Other Related Costs The Company incurred severance and other business optimization costs of $238 and $1,336 for the three months ended September 30, 2017 and 2016 , respectively, and $880 and $6,402 for the nine months ended September 30, 2017 and 2016 , respectively. These costs were not associated with formal restructuring plans and primarily related to severance charges for certain executives, transition/duplicate staffing, professional fees and other expenses related to the Company’s organizational changes.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share: Basic earnings per share is calculated as income (loss) available to common stockholders, divided by the weighted average number of common shares outstanding during the period for each class of common stock, respectively. Diluted earnings per share is calculated as income (loss) available to common stockholders, divided by the weighted average number of common and potential common shares outstanding during the period for each class of common stock, if dilutive. The reconciliation from basic to diluted weighted average shares outstanding is as follows: Three months ended Nine months ended 2017 2016 2017 2016 Weighted average common shares outstanding – Basic 104,096,837 103,783,719 104,020,180 81,986,221 Dilutive effect of unvested common shares with service conditions and assumed stock option exercises and conversions — — — — Weighted average common shares outstanding – Diluted 104,096,837 103,783,719 104,020,180 81,986,221 The following table reconciles the components of basic and diluted loss per share for the three and nine months ended September 30, 2017 and 2016 : Three months ended Nine months ended 2017 2016 2017 2016 Numerator: Net loss attributable to PQ Group Holdings Inc. $ (3,345 ) $ (10,017 ) $ (7,408 ) $ (90,410 ) Denominator: Weighted average common shares outstanding – Basic 104,096,837 103,783,719 104,020,180 81,986,221 Weighted average common shares outstanding – Diluted 104,096,837 103,783,719 104,020,180 81,986,221 Net loss per common share: Basic earnings per share $ (0.03 ) $ (0.10 ) $ (0.07 ) $ (1.10 ) Diluted earnings per share $ (0.03 ) $ (0.10 ) $ (0.07 ) $ (1.10 )

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events: On September 29, 2017, the Company’s common stock began trading on the New York Stock Exchange under the symbol “PQG”. On October 3, 2017, the Company completed the IPO of its common stock at a price to the public of $17.50 per share. The Company issued and sold 29,000,000 shares of common stock in the IPO. The Company raised net proceeds of approximately $480,525 from the IPO, after deducting underwriting discounts, commissions and related offering expenses, net of reimbursements. The Company used the net proceeds of the IPO to repay debt together with accrued and unpaid interest and applicable redemption premiums (see Note 12 to these condensed consolidated financial statements for further information). In connection with the reclassification, stock split and conversion transactions associated with the IPO related to the Company’s Class A and Class B common stock (see Note 1 to these condensed consolidated financial statements for further information), the Company’s outstanding restricted stock and stock option awards were converted on the same basis, including equivalent adjustments to the respective exercise prices with respect to the stock option awards. The vesting and other terms of the restricted stock and stock option awards were otherwise unchanged. In connection with the IPO, the Company’s board of directors adopted the PQ Group Holdings Inc. 2017 Omnibus Incentive Plan (the “2017 Plan”), with all future equity awards of the Company to be issued under the 2017 Plan. On October 2, 2017, the Company granted the following equity awards related to its common stock to certain of its officers, employees and directors in connection with the IPO: 1,654,685 restricted stock units; 621,747 stock options; and 21,067 stock awards. The restricted stock units and stock options are subject to service vesting conditions, while the stock awards were immediately vested upon grant. The Company has evaluated subsequent events since the balance sheet date and determined that, other than the items noted above, there are no additional items to disclose.

Background and Basis of Prese28

Background and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation On August 17, 2015, the Company, PQ Holdings Inc. (“PQ Holdings”), Eco Services Operations LLC (“Eco Services”), certain investment funds affiliated with CCMP Capital Advisors, LLC (now known as CCMP Capital Advisors, LP; “CCMP”), and stockholders of PQ Holdings and Eco Services entered into a reorganization and transaction agreement pursuant to which the companies consummated a series of transactions to reorganize and combine the businesses of PQ Holdings and Eco Services (the “Business Combination”), under a new holding company, PQ Group Holdings Inc. The Business Combination was consummated on May 4, 2016. In accordance with accounting principles generally accepted in the United States (“GAAP”), Eco Services is the accounting predecessor to PQ Group Holdings. Certain investment funds affiliated with CCMP held a controlling interest position in Eco Services prior to the Business Combination. In addition, certain investment funds affiliated with CCMP owned a non-controlling interest in PQ Holdings prior to the Business Combination and the merger with Eco Services constituted a change in control under the PQ Holdings credit agreements and bond indenture that were in place at the time of the Business Combination. Therefore, Eco Services is deemed to be the accounting acquirer. These condensed consolidated financial statements are the continuation of Eco Services’ business prior to the Business Combination. The condensed consolidated financial statements included herein are unaudited. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations for interim reporting. In the opinion of management, all adjustments of a normal and recurring nature necessary to state fairly the financial position and results of operations have been included. The results of operations are not necessarily indicative of the results to be expected for the full year. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s prospectus dated September 28, 2017, as filed with the SEC pursuant to Rule 424(b) under the Securities Act of 1933, as amended.
Recently Issued Accounting Standards	Recently Adopted Accounting Standards In October 2016, the Financial Accounting Standards Board (“FASB”) issued guidance which eliminates the deferral of the tax effects of intra-entity transfers of an asset other than inventory. Previous GAAP prohibited the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset had been sold to an outside party which has resulted in diversity in practice and increased complexity within financial reporting. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company early adopted the guidance effective January 1, 2017. The guidance did not have a material impact on the Company’s consolidated financial statements. In March 2016, the FASB issued guidance that includes targeted improvements to the accounting for employee stock-based compensation. The updates in the guidance include changes in the income tax consequences, balance sheet classification and cash flow statement reporting of stock-based payment transactions. The guidance also includes certain modifications applicable only to nonpublic entities. For public companies, the new guidance is effective for annual periods beginning after December 15, 2016, and interim periods within those years. The Company adopted this new guidance as required on January 1, 2017, with no material impact upon adoption to the Company’s consolidated financial statements. On a prospective basis from the adoption date, the Company will record all tax effects related to stock-based compensation through the statement of operations, and all tax-related cash flows resulting from stock-based award payments will be reported as operating activities in the statement of cash flows. The Company made an accounting policy election under the new guidance to account for forfeitures of stock-based compensation awards as they occur. In July 2015, the FASB issued new guidance that changes the measurement principle for inventory from the lower of cost or market to the lower of cost or net realizable value. The amendments in this guidance do not apply to inventory that is measured using LIFO or the retail inventory method; rather, the amendments apply to all other inventory, which includes inventory that is measured using FIFO or average cost. Within the scope of this new guidance, an entity should measure inventory at the lower of cost or net realizable value. Net realizable value is defined as the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation, which is consistent with existing GAAP. The Company adopted the new guidance on January 1, 2017 as required. The guidance did not have a material impact on the Company’s consolidated financial statements. Accounting Standards Not Yet Adopted In August 2017, the FASB issued amendments intended to better align hedge accounting with an entities risk management activities. The amendments expand hedge accounting for non-financial and financial risk components and revise the measurement methodologies to better align with an entities risk management activities. Separate presentation of hedge ineffectiveness is eliminated to provide greater transparency of the full impact of hedging by requiring presentation of the results of the hedged item and hedging instrument in a single financial statement line item. In addition, the amendments reduce complexity by simplifying the manner in which assessments of hedge effectiveness may be performed. The new guidance is effective for public companies for annual periods beginning after December 15, 2018, including interim periods within those years. Early adoption is permitted, and the new guidance should be applied prospectively to the presentation and disclosure guidance. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In May 2017, the FASB issued guidance to clarify which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. Under the new guidance, an entity should not account for the effects of a change in a share-based payment award using modification accounting unless the fair value, vesting conditions and classification as either a liability or equity are all the same with respect to the award immediately prior to modification and the modified award itself. The new guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those years. Early adoption is permitted, and the new guidance should be applied prospectively to awards modified on or after the adoption date. Based on the Company’s existing policies regarding the application of modification accounting to its share-based payment awards, the Company does not believe that the new guidance will have a material impact on its consolidated financial statements. In March 2017, the FASB issued guidance to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost (collectively, “pension costs”). Under current GAAP, there are several components of pension costs which are presented net to arrive at pension costs as included in the income statement and disclosed in the notes. As part of this amendment to the existing guidance, the service cost component of pension costs will be bifurcated from the other components and included in the same line item of the income statement as compensation costs are reported. The remaining components will be reported together below operating income on the income statement, either as a separate line item or combined with another line item on the income statement and disclosed. Additionally, with respect to capitalization to inventory, fixed assets, etc., only the service cost component will be eligible for capitalization upon adoption of the guidance. The new guidance is effective for public companies for annual periods beginning after December 15, 2017, including interim periods within those years. Early adoption is permitted. The amendments should be applied retrospectively upon adoption with respect to the presentation of the service and other cost components of pension costs in the income statement, and prospectively for the capitalization of the service cost component in assets. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In January 2017, the FASB issued guidance which eliminates the second step from the traditional two-step goodwill impairment test. Under current guidance, an entity performed the first step of the goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount; if an impairment loss was indicated, the entity computed the implied fair value of goodwill to determine whether an impairment loss existed, and if so, the amount to recognize. Under the new guidance, an impairment loss is recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value (the Step 1 test), with no further testing required. Any impairment loss recognized is limited to the amount of goodwill allocated to the reporting unit. The new guidance is effective for public companies that are SEC registrants for fiscal years beginning after December 15, 2019, with early adoption permitted for goodwill impairment tests performed on testing dates after January 1, 2017. All entities are required to apply the guidance prospectively to goodwill impairment tests subsequent to adoption of the standard. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In January 2017, the FASB issued guidance which clarifies the definition of a business and provides revised criteria and a framework to determine whether an integrated set of assets and activities is a business. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those years. Early adoption is permitted. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In November 2016, the FASB issued guidance which clarifies the classification and presentation of changes in restricted cash on the statement of cash flows. The updates in the guidance require that the statement of cash flows explain the change during the period in the total of cash, cash equivalents and restricted cash when reconciling the beginning-of-period and end-of-period total amounts. The updates also require a reconciliation between cash, cash equivalents and restricted cash presented on the balance sheet to the total of the same amounts presented on the statement of cash flows. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those years. Early adoption is permitted, and the new guidance should be applied retrospectively to each period presented. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. As of September 30, 2017 , the Company had $ 1,645 of restricted cash included in prepaid and other current assets on its balance sheet related to its New Market Tax Credit financing arrangements as well as other small restricted cash balances. In August 2016, the FASB issued guidance which clarifies the classification of certain cash receipts and cash payments in the statement of cash flows, including debt prepayment or extinguishment costs and distributions from certain equity method investees. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, and the new guidance should be applied retrospectively to each period presented. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements. In February 2016, the FASB issued guidance that amends the accounting for leases. Under the new guidance, a lessee will recognize assets and liabilities for most leases (including those classified under existing GAAP as operating leases, which based on current standards are not reflected on the balance sheet), but will recognize expenses similar to current lease accounting. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. Early adoption is permitted. The new guidance must be adopted using a modified retrospective transition and provides for certain practical expedients. The Company is currently evaluating the impact that the new guidance will have on its consolidated financial statements. The Company has operating lease agreements for which it expects to recognize right of use assets and corresponding liabilities on its balance sheet upon adoption of the new guidance. A complete discussion of these leases is included in the Company’s audited consolidated financial statements for the year ended December 31, 2016 in Note 20, Commitments and Contingent Liabilities. In May 2014, the FASB issued accounting guidance (with subsequent targeted amendments) that will significantly enhance comparability of revenue recognition practices across entities, industries, jurisdictions and capital markets. The core principle of the guidance is that revenue recognized from a transaction or event that arises from a contract with a customer should reflect the consideration to which an entity expects to be entitled in exchange for goods or services provided. To achieve that core principle, the new guidance sets forth a five-step revenue recognition model that will need to be applied consistently to all contracts with customers, except those that are within the scope of other topics in the Accounting Standards Codification (“ASC”). Also required are enhanced disclosures to help users of financial statements better understand the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. The enhanced disclosures include qualitative and quantitative information about contracts with customers, significant judgments made in applying the revenue guidance, and assets recognized related to the costs to obtain or fulfill a contract. For public companies, the new requirements are effective for annual reporting periods beginning after December 15, 2017, including interim periods within those years. The Company is reviewing its key revenue streams and assessing the underlying customer contracts within the framework of the new guidance. The Company has evaluated the key aspects of its revenue streams for impact under the new guidance and is currently performing a detailed analysis of its customer agreements to quantify the potential changes under the guidance. The Company believes that the guidance will not have a material impact on its existing revenue recognition practices, but there are new robust disclosure requirements that will have an impact on the Company’s reporting. The Company anticipates adopting the new guidance in the first quarter of 2018 as required, and expects to implement the guidance under the modified retrospective transition method of adoption.
Fair Value Measurement	Restoration plan assets The fair values of the Company’s restoration plan assets are determined through quoted prices in active markets. Restoration plan assets are assets held in a Rabbi trust to fund the obligations of the Company’s defined benefit supplementary retirement plans and include various stock and fixed income mutual funds. See Note 15 to these condensed consolidated financial statements regarding defined supplementary retirement plans. Derivative contracts Derivative assets and liabilities can be exchange-traded or traded over-the-counter (“OTC”). The Company generally values exchange-traded derivatives using models that calibrate to market transactions and eliminate timing differences between the closing price of the exchange-traded derivatives and their underlying instruments. OTC derivatives are valued using market transactions and other market evidence whenever possible, including market-based inputs to models, model calibration to market transactions, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency. When models are used, the selection of a particular model to value an OTC derivative depends on the contractual terms of, and specific risks inherent in, the instrument as well as the availability of pricing information in the market. The Company generally uses similar models to value similar instruments. Valuation models require a variety of inputs, including contractual terms, market prices and rates, forward curves, measures of volatility, and correlations of such inputs. For OTC derivatives that trade in liquid markets, such as forward contracts, swaps and options, model inputs can generally be corroborated by observable market data by correlation or other means, and model selection does not involve significant management judgment. The Company has interest rate caps and natural gas caps and swaps that are fair valued using Level 2 inputs. In addition, the Company applies a credit valuation adjustment to reflect credit risk which is calculated based on credit default swaps. To the extent that the Company’s net exposure under a specific master agreement is an asset, the Company utilizes the counterparty’s default swap rate. If the net exposure under a specific master agreement is a liability, the Company utilizes a default swap rate comparable to PQ Group Holdings. The credit valuation adjustment is added to the discounted fair value to reflect the exit price that a market participant would be willing to receive to assume the Company’s liabilities or that a market participant would be willing to pay for the Company’s assets.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring	The following table presents information about the Company’s assets and liabilities that were measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 , and indicates the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. As of September 30, 2017 Quoted Prices in Significant Other Significant (Level 3) Assets: Derivative contracts $ 1,098 $ — $ 1,098 $ — Restoration plan assets 5,566 5,566 — — Total $ 6,664 $ 5,566 $ 1,098 $ — Liabilities: Derivative contracts $ 58 $ — $ 58 $ — As of December 31, 2016 Quoted Prices in Significant Other Significant (Level 3) Assets: Derivative contracts $ 6,434 $ — $ 6,434 $ — Restoration plan assets 5,594 5,594 — — Total $ 12,028 $ 5,594 $ 6,434 $ —

Accumulated Other Comprehensi30

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table presents the tax effects of each component of other comprehensive income (loss) for the three and nine months ended September 30, 2017 and 2016 : Three months ended September 30, 2017 2016 Pre-tax Tax After-tax Pre-tax Tax After-tax Defined benefit and other postretirement plans Amortization and unrealized losses $ (33 ) $ 13 $ (20 ) $ 162 $ — $ 162 Benefit plans, net (33 ) 13 (20 ) 162 — 162 Net loss (gain) from hedging activities (486 ) 185 (301 ) 324 (123 ) 201 Foreign currency translation 21,343 (2,493 ) 18,850 1,930 (644 ) 1,286 Other comprehensive income (loss) $ 20,824 $ (2,295 ) $ 18,529 $ 2,416 $ (767 ) $ 1,649 Nine months ended September 30, 2017 2016 Pre-tax Tax After-tax Pre-tax Tax After-tax Defined benefit and other postretirement plans Amortization and unrealized losses $ (261 ) $ 38 $ (223 ) $ 486 $ — $ 486 Benefit plans, net (261 ) 38 (223 ) 486 — 486 Net loss (gain) from hedging activities (5,373 ) 2,047 (3,326 ) 2,100 (798 ) 1,302 Foreign currency translation 69,202 (8,710 ) 60,492 (9,605 ) 1,686 (7,919 ) Other comprehensive income (loss) $ 63,568 $ (6,625 ) $ 56,943 $ (7,019 ) $ 888 $ (6,131 ) The following table presents the change in accumulated other comprehensive income (loss), net of tax, by component for the nine months ended September 30, 2017 and 2016 : Defined benefit Net gain (loss) Foreign Total December 31, 2016 $ 7,513 $ 4,557 $ (65,781 ) $ (53,711 ) Other comprehensive income (loss) before reclassifications (322 ) (3,404 ) 60,238 56,512 Amounts reclassified from accumulated other comprehensive income (a) 99 78 — 177 Net current period other comprehensive income (loss) (223 ) (3,326 ) 60,238 56,689 September 30, 2017 $ 7,290 $ 1,231 $ (5,543 ) $ 2,978 December 31, 2015 $ 648 $ — $ — $ 648 Other comprehensive income (loss) before reclassifications 486 591 (7,306 ) (6,229 ) Amounts reclassified from accumulated other comprehensive income (a) — 711 — 711 Net current period other comprehensive income (loss) 486 1,302 (7,306 ) (5,518 ) September 30, 2016 $ 1,134 $ 1,302 $ (7,306 ) $ (4,870 ) ————— (a) See the following table for details about these reclassifications.
Reclassification out of Accumulated Other Comprehensive Income	The following table presents the reclassifications out of accumulated other comprehensive income (loss) for the three and nine months ended September 30, 2017 and 2016 . Amounts in parenthesis indicate debits to profit/loss. Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Affected Line Item in the Three months ended Nine months ended 2017 2016 2017 2016 Defined benefit and other postretirement plans Amortization of prior service cost $ 20 $ — $ 60 $ — (a) Amortization of net gain (loss) 19 — 58 — (a) 39 — 118 — Total before tax (6 ) — (19 ) — Tax (expense) benefit $ 33 $ — $ 99 $ — Net of tax Net gain (loss) from hedging activities Interest rate caps $ 13 $ (2 ) $ 22 $ (2 ) Interest expense Natural gas swaps 94 420 104 1,148 Cost of goods sold 107 418 126 1,146 Total before tax (41 ) (159 ) (48 ) (435 ) Tax (expense) benefit $ 66 $ 259 $ 78 $ 711 Net of tax Total reclassifications for the period $ 99 $ 259 $ 177 $ 711 Net of tax ————— (a) These accumulated other comprehensive income (loss) components are included in the computation of net periodic pension and other postretirement cost (see Note 15 to these condensed consolidated financial statements for additional details).

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Preliminary Purchase Price Allocation	The following table sets forth the calculation and preliminary allocation of the purchase price to the identifiable net assets acquired with respect to the Acquisition: Total consideration, net of cash acquired $ 41,572 Recognized amounts of identifiable assets acquired and liabilities assumed: Receivables $ 14,305 Inventories 7,645 Prepaid and other current assets 230 Property, plant and equipment 9,020 Other long-term assets 129 Fair value of assets acquired 31,329 Current debt (6,420 ) Accounts payable (10,748 ) Long-term debt (10,189 ) Other long-term liabilities (154 ) Fair value of net assets acquired 3,818 Goodwill 37,754 $ 41,572
Business Acquisition, Pro Forma Information	The results of operations for the three months ended September 30, 2017 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Three months ended September 30, Nine months ended 2016 2017 2016 (unaudited) Pro forma sales $ 381,065 $ 1,130,454 $ 772,549 Pro forma net loss (8,289 ) (6,511 ) (88,300 ) The results of operations for the three months ended September 30, 2016 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Nine months ended September 30, 2016 (unaudited) Pro forma sales $ 1,080,310 Pro forma net loss (55,985 )

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Business Acquisition, Pro Forma Information	The results of operations for the three months ended September 30, 2017 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Three months ended September 30, Nine months ended 2016 2017 2016 (unaudited) Pro forma sales $ 381,065 $ 1,130,454 $ 772,549 Pro forma net loss (8,289 ) (6,511 ) (88,300 ) The results of operations for the three months ended September 30, 2016 include the operating results of the combined company for the full period and therefore, there is no pro forma presentation included in the table below. Nine months ended September 30, 2016 (unaudited) Pro forma sales $ 1,080,310 Pro forma net loss (55,985 )

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amount of goodwill for the nine months ended September 30, 2017 is summarized as follows: Performance Environmental Total Balance as of December 31, 2016 $ 852,506 $ 388,923 $ 1,241,429 Goodwill recognized 37,754 — 37,754 Foreign exchange impact 25,189 2,175 27,364 Balance as of September 30, 2017 $ 915,449 $ 391,098 $ 1,306,547

Other Operating Expense, Net (T

Other Operating Expense, Net (Tables)	9 Months Ended
	Sep. 30, 2017
Other Income and Expenses [Abstract]
Schedule of Other Nonoperating Income (Expense)	A summary of other operating expense, net is as follows: Three months ended Nine months ended 2017 2016 2017 2016 Restructuring and other related costs (Note 18) $ 4,106 $ 1,336 $ 5,578 $ 10,898 Amortization expense 9,146 8,914 23,270 17,029 Net loss on asset disposals 3,494 627 6,419 2,288 Transaction and other related costs (1) 966 1,635 5,295 6,063 Management advisory fees 1,250 1,250 3,750 2,333 Other, net 871 1,280 2,844 2,019 $ 19,833 $ 15,042 $ 47,156 $ 40,630 ————— (1) Transaction and other related costs primarily include acquisition costs directly attributable to the Acquisition (see Note 5 to these condensed consolidated financial statements for further information) and the Business Combination (see Note 6 to these condensed consolidated financial statements for further information), as well as other business development costs.

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2017
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	Inventories are classified and valued as follows: September 30, 2017 December 31, 2016 Finished products and work in process $ 178,844 $ 175,182 Raw materials 57,077 51,866 $ 235,921 $ 227,048 Valued at lower of cost or market: LIFO basis $ 145,905 $ 135,605 FIFO or average cost basis 90,016 91,443 $ 235,921 $ 227,048

Investments in Affiliated Com36

Investments in Affiliated Companies (Tables)	9 Months Ended
	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	The Company accounts for investments in affiliated companies under the equity method. Affiliated companies accounted for on the equity basis as of September 30, 2017 are as follows: Company Country Percent PQ Silicates Ltd. Taiwan 50% Zeolyst International USA 50% Zeolyst C.V. Netherlands 50% Quaker Holdings South Africa 49% Following is summarized information of the combined investments: Three months ended Nine months ended 2017 2016 2017 2016 Net sales $ 83,983 $ 63,110 $ 225,770 $ 107,897 Gross profit 33,276 24,283 91,862 46,589 Operating income 22,713 15,054 60,408 30,708 Net income 23,819 15,351 63,663 30,994

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	A summary of property, plant and equipment, at cost, and related accumulated depreciation is as follows: September 30, 2017 December 31, 2016 Land $ 191,917 $ 186,327 Buildings 191,916 157,944 Machinery and equipment 955,779 788,175 Construction in progress 155,005 204,138 1,494,617 1,336,584 Less: accumulated depreciation (285,570 ) (155,196 ) $ 1,209,047 $ 1,181,388

Long-term Debt (Tables)

Long-term Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The summary of long-term debt is as follows: September 30, 2017 December 31, 2016 Term Loan Facility (U.S. dollar denominated) $ 918,473 $ 925,430 Term Loan Facility (Euro denominated) 331,368 297,317 6.75% Senior Secured Notes due 2022 625,000 625,000 Floating Rate Senior Unsecured Notes due 2022 525,000 525,000 8.5% Senior Notes due 2022 200,000 200,000 ABL Facility 35,000 — Other 68,207 45,223 Total debt 2,703,048 2,617,970 Original issue discount (26,470 ) (28,497 ) Deferred financing costs (24,842 ) (27,275 ) Total debt, net of original issue discount and deferred financing costs 2,651,736 2,562,198 Less: current portion (54,255 ) (14,481 ) Total long-term debt $ 2,597,481 $ 2,547,717

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivatives Held	The fair values of derivative instruments held as of September 30, 2017 and December 31, 2016 are shown below: Balance sheet location September 30, 2017 December 31, 2016 Asset derivatives: Derivatives designated as cash flow hedges: Natural gas swaps Current assets $ — $ 573 Interest rate caps Current assets 9 — Natural gas swaps Other long-term assets 7 58 Interest rate caps Other long-term assets 1,082 5,803 Total asset derivatives $ 1,098 $ 6,434 Liability derivatives: Derivatives designated as cash flow hedges: Natural gas swaps Accrued liabilities $ 58 $ — Total liability derivatives $ 58 $ —
Effect of Derivative Instruments Designated as Hedges on Other Comprehensive Income	The following tables show the effect of the Company’s derivative instruments designated as hedges on other comprehensive income (loss) (“OCI”) and the statement of income for the three and nine months ended September 30, 2017 and 2016 : Three months ended September 30, 2017 2016 Derivatives designated as cash flow hedges: Location in Earnings Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Interest rate caps Interest expense $ (1,842 ) $ 13 $ 212 $ (2 ) Natural gas swaps Cost of goods sold (28) 94 (306) 420 $ (1,870 ) $ 107 $ (94 ) $ 418 Nine months ended September 30, 2017 2016 Derivatives designated as cash flow hedges: Location in Earnings Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Amount of gain (loss) recognized in OCI on derivatives (effective portion) Amount of gain (loss) reclassified from accumulated OCI into income (effective portion) Interest rate caps Interest expense $ (4,712 ) $ 22 $ 212 $ (2 ) Natural gas swaps Cost of goods sold (787) 104 (1,723) 1,148 $ (5,499 ) $ 126 $ (1,511 ) $ 1,146

Benefit Plans (Tables)

Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Expense	Components of net periodic expense are as follows: Defined Benefit Pension Plans U.S. Foreign Three months ended Three months ended 2017 2016 2017 2016 Service cost $ 305 $ 547 $ 859 $ 792 Interest cost 2,536 2,522 1,339 837 Expected return on plan assets (3,061 ) (3,104 ) (1,111 ) (769 ) Net periodic expense (benefit) $ (220 ) $ (35 ) $ 1,087 $ 860 U.S. Foreign Nine months ended Nine months ended 2017 2016 2017 2016 Service cost $ 914 $ 1,640 $ 2,642 $ 1,320 Interest cost 7,608 5,236 4,024 1,396 Expected return on plan assets (9,183 ) (6,176 ) (3,329 ) (1,283 ) Net periodic expense (benefit) $ (661 ) $ 700 $ 3,337 $ 1,433
Supplemental Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Expense	Supplemental Retirement Plans Three months ended Nine months ended 2017 2016 2017 2016 Interest cost $ 123 $ 121 $ 370 $ 202 Net periodic expense $ 123 $ 121 $ 370 $ 202
Other Postretirement Benefits Plans
Defined Benefit Plan Disclosure [Line Items]
Components of Net Periodic Expense	Other Postretirement Benefit Plans Three months ended September 30, Nine months ended September 30, 2017 2016 2017 2016 Service cost $ 5 $ 9 $ 15 $ 28 Interest cost 40 53 122 110 Amortization of prior service credit (19 ) — (58 ) — Amortization of net gain (19 ) — (58 ) — Net periodic expense $ 7 $ 62 $ 21 $ 138

Reportable Segments (Tables)

Reportable Segments (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Reconciliation of Revenue from Reportable Segments to Consolidated	Summarized financial information for the Company’s (1) Performance Materials & Chemicals and (2) Environmental Catalysts & Services reportable segments is shown in the following table: Three months ended Nine months ended 2017 2016 2017 2016 Net sales: Performance Materials & Chemicals $ 277,072 $ 256,219 $ 765,781 $ 429,867 Environmental Catalysts & Services (1) 115,541 114,271 350,814 312,490 Eliminations (2) (784 ) (511 ) (2,568 ) (911 ) Total $ 391,829 $ 369,979 $ 1,114,027 $ 741,446 Segment Adjusted EBITDA: (3) Performance Materials & Chemicals $ 65,885 $ 64,604 $ 184,741 $ 111,178 Environmental Catalysts & Services (4) 61,900 56,341 182,578 135,044 Total Segment Adjusted EBITDA (5) $ 127,785 $ 120,945 $ 367,319 $ 246,222 ————— (1) Excludes the Company’s proportionate share of sales from the Zeolyst International and Zeolyst C.V. joint ventures (collectively, the “Zeolyst Joint Venture”) accounted for using the equity method (see Note 10 to these condensed consolidated financial statements for further information). The proportionate share of sales is $37,622 and $28,184 for the three months ended September 30, 2017 and 2016 , respectively. The proportionate share of sales is $100,991 and $48,461 for the nine months ended September 30, 2017 and 2016 , respectively. (2) The Company eliminates intersegment sales when reconciling to the Company’s consolidated statements of operations. (3) The Company defines Adjusted EBITDA as EBITDA adjusted for certain items as noted in the reconciliation below. Management evaluates the performance of its segments and allocates resources based on several factors, of which the primary measure is Adjusted EBITDA. Adjusted EBITDA should not be considered as an alternative to net income as an indicator of the Company’s operating performance. Adjusted EBITDA as defined by the Company may not be comparable with EBITDA or Adjusted EBITDA as defined by other companies. (4) The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $14,398 for the three months ended September 30, 2017, which includes $10,151 of equity in net income plus $1,658 of amortization of investment in affiliate step-up plus $2,563 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $10,316 for the three months ended September 30, 2016, which includes $4,683 of equity in net loss plus $12,291 of amortization of investment in affiliate step-up plus $2,690 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $39,690 for the nine months ended September 30, 2017, which includes $24,594 of equity in net income plus $6,941 of amortization of investment in affiliate step-up plus $8,073 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the environmental catalyst and services segment is $19,962 for the nine months ended September 30, 2016, which includes $9,213 of equity in net loss plus $24,606 of amortization of investment in affiliate step-up plus $4,534 of joint venture depreciation, amortization and interest. (5) Total Segment Adjusted EBITDA differs from the Company’s consolidated Adjusted EBITDA due to unallocated corporate expenses.
Reconciliation of Net Loss to Segment Adjusted EBITDA	A reconciliation from net loss to Segment Adjusted EBITDA is as follows: Three months ended Nine months ended 2017 2016 2017 2016 Reconciliation of net loss attributable to PQ Group Holdings Inc. to Segment Adjusted EBITDA Net loss attributable to PQ Group Holdings Inc. $ (3,345 ) $ (10,017 ) $ (7,408 ) $ (90,410 ) Provision for (benefit from) income taxes 5,172 (3,536 ) 5,269 36,013 Interest expense, net 49,079 48,610 144,041 94,362 Depreciation and amortization 45,929 43,611 129,135 85,602 Segment EBITDA 96,835 78,668 271,037 125,567 Unallocated corporate expenses 7,885 7,316 23,474 13,940 Joint venture depreciation, amortization and interest 2,563 2,690 8,073 4,534 Amortization of investment in affiliate step-up 1,660 12,291 6,942 24,606 Amortization of inventory step-up — 5,804 871 23,518 Debt extinguishment costs 453 — 453 11,858 Losses on disposal of fixed assets 3,494 627 6,419 2,288 Foreign currency exchange losses 5,256 3,151 21,612 6,240 Non-cash revaluation of inventory, including LIFO 750 329 3,229 775 Management advisory fees 1,250 1,250 3,750 2,333 Transaction and other related costs 966 1,696 5,300 6,240 Equity-based and other non-cash compensation 1,041 1,137 3,869 4,916 Restructuring, integration and business optimization expenses 4,957 2,839 8,009 14,567 Defined benefit pension plan cost 791 1,244 2,200 2,642 Other (116 ) 1,903 2,081 2,198 Segment Adjusted EBITDA $ 127,785 $ 120,945 $ 367,319 $ 246,222

Restructuring and Other Relat42

Restructuring and Other Related Costs (Tables)	9 Months Ended
	Sep. 30, 2017
Restructuring and Related Activities [Abstract]
Components of Restructuring and Other Related Costs	The following table presents the components of restructuring and other related costs for the three and nine months ended September 30, 2017 and 2016 : Three months ended Nine months ended 2017 2016 2017 2016 Severance and other employee costs related to legacy Eco restructuring plan $ — $ — $ 830 $ 4,496 Severance and other employee costs related to performance materials plant closure 3,868 — 3,868 — Other related costs 238 1,336 880 6,402 $ 4,106 $ 1,336 $ 5,578 $ 10,898
Activity in Restructuring Plan	The activity in the accrued liability balance associated with the Company’s restructuring plans, all of which related to severance and other employee costs, was as follows for the nine months ended September 30, 2017 : Legacy Eco Restructuring Plan Performance Materials Plant Closure Total Restructuring Charges Balance at December 31, 2016 $ 1,643 $ — $ 1,643 Restructuring charges 830 3,868 4,698 Cash payments (1,971 ) — (1,971 ) Balance at September 30, 2017 $ 502 $ 3,868 $ 4,370

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Schedule of from Basic to Diluted Weighted Average Number of Shares Outstanding	The reconciliation from basic to diluted weighted average shares outstanding is as follows: Three months ended Nine months ended 2017 2016 2017 2016 Weighted average common shares outstanding – Basic 104,096,837 103,783,719 104,020,180 81,986,221 Dilutive effect of unvested common shares with service conditions and assumed stock option exercises and conversions — — — — Weighted average common shares outstanding – Diluted 104,096,837 103,783,719 104,020,180 81,986,221
Schedule of Earnings Per Share, Basic and Diluted	The following table reconciles the components of basic and diluted loss per share for the three and nine months ended September 30, 2017 and 2016 : Three months ended Nine months ended 2017 2016 2017 2016 Numerator: Net loss attributable to PQ Group Holdings Inc. $ (3,345 ) $ (10,017 ) $ (7,408 ) $ (90,410 ) Denominator: Weighted average common shares outstanding – Basic 104,096,837 103,783,719 104,020,180 81,986,221 Weighted average common shares outstanding – Diluted 104,096,837 103,783,719 104,020,180 81,986,221 Net loss per common share: Basic earnings per share $ (0.03 ) $ (0.10 ) $ (0.07 ) $ (1.10 ) Diluted earnings per share $ (0.03 ) $ (0.10 ) $ (0.07 ) $ (1.10 )

Background and Basis of Prese44

Background and Basis of Presentation (Details) $ / shares in Units, $ in Thousands	Oct. 03, 2017USD ($)$ / sharesshares	Sep. 28, 2017	Sep. 30, 2017segment	Sep. 29, 2017$ / shares
Subsidiary or Equity Method Investee
Number of operating segments | segment			2
Stock split, conversion ratio		8.8275
Unreturned paid-in capital per share (usd per share)				$ 113.74
Subsequent Event | IPO
Subsidiary or Equity Method Investee
Price of shares issued (usd per share)	$ 17.50
Shares issued (shares) | shares	29,000,000
Proceeds from initial public offering | $	$ 480,525

New Accounting Standards (Detai

New Accounting Standards (Details) $ in Thousands	Sep. 30, 2017USD ($)
Accounting Changes and Error Corrections [Abstract]
Restricted cash	$ 1,645

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets:
Derivative contracts	$ 1,098	$ 6,434
Restoration plan assets	5,566	5,594
Total	6,664	12,028
Liabilities:
Derivative contracts	58
Quoted Prices in Active Markets (Level 1)
Assets:
Derivative contracts	0	0
Restoration plan assets	5,566	5,594
Total	5,566	5,594
Liabilities:
Derivative contracts	0
Significant Other Observable Inputs (Level 2)
Assets:
Derivative contracts	1,098	6,434
Restoration plan assets	0	0
Total	1,098	6,434
Liabilities:
Derivative contracts	58
Significant Unobservable Inputs (Level 3)
Assets:
Derivative contracts	0	0
Restoration plan assets	0	0
Total	0	$ 0
Liabilities:
Derivative contracts	$ 0

Accumulated Other Comprehensi47

Accumulated Other Comprehensive Income (Loss) - Pre-tax and After-tax Components of Other Comprehensive Inoome (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
After-tax amount
Pre-tax amount	$ 20,824	$ 2,416	$ 63,568	$ (7,019)
Tax benefit / (expense)	(2,295)	(767)	(6,625)	888
Total other comprehensive income (loss)	18,529	1,649	56,943	(6,131)
Defined benefit and other postretirement plans
After-tax amount
Pre-tax amount	(33)	162	(261)	486
Tax benefit / (expense)	13	0	38	0
Total other comprehensive income (loss)	(20)	162	(223)	486
Net loss (gain) from hedging activities
After-tax amount
Pre-tax amount	(486)	324	(5,373)	2,100
Tax benefit / (expense)	185	(123)	2,047	(798)
Total other comprehensive income (loss)	(301)	201	(3,326)	1,302
Foreign currency translation
After-tax amount
Pre-tax amount	21,343	1,930	69,202	(9,605)
Tax benefit / (expense)	(2,493)	(644)	(8,710)	1,686
Total other comprehensive income (loss)	$ 18,850	$ 1,286	$ 60,492	$ (7,919)

Accumulated Other Comprehensi48

Accumulated Other Comprehensive Income (Loss) - Change by Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance			$ 1,027,944	$ 235,293
Amounts reclassified from accumulated other comprehensive income	$ 99	$ 259	177	711
Total other comprehensive income (loss)	18,529	1,649	56,943	(6,131)
Ending balance	1,080,970	1,066,733	1,080,970	1,066,733
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance			(53,711)	648
Other comprehensive income (loss) before reclassifications			56,512	(6,229)
Amounts reclassified from accumulated other comprehensive income			177	711
Total other comprehensive income (loss)			56,689	(5,518)
Ending balance	2,978	(4,870)	2,978	(4,870)
Defined benefit and other postretirement plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance			7,513	648
Other comprehensive income (loss) before reclassifications			(322)	486
Amounts reclassified from accumulated other comprehensive income	33	0	99	0
Total other comprehensive income (loss)			(223)	486
Ending balance	7,290	1,134	7,290	1,134
Net gain (loss) from hedging activities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance			4,557	0
Other comprehensive income (loss) before reclassifications			(3,404)	591
Amounts reclassified from accumulated other comprehensive income			78	711
Total other comprehensive income (loss)			(3,326)	1,302
Ending balance	1,231	1,302	1,231	1,302
Foreign currency translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax
Beginning balance			(65,781)	0
Other comprehensive income (loss) before reclassifications			60,238	(7,306)
Amounts reclassified from accumulated other comprehensive income			0	0
Total other comprehensive income (loss)			60,238	(7,306)
Ending balance	$ (5,543)	$ (7,306)	$ (5,543)	$ (7,306)

Accumulated Other Comprehensi49

Accumulated Other Comprehensive Income (Loss) - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification, net	$ 99	$ 259	$ 177	$ 711
Interest expense	49,079	48,610	144,041	94,362
Cost of goods sold	289,270	274,680	821,342	557,748
Income (loss) before income taxes and noncontrolling interest	(2,156)	13,142	1,732	53,672
Tax (expense) benefit	5,172	(3,536)	5,269	36,013
Net loss	3,016	9,606	7,001	89,685
Defined benefit and other postretirement plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification, before tax	39	0	118	0
Reclassification, tax	(6)	0	(19)	0
Reclassification, net	33	0	99	0
Amortization of prior service cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification, before tax	20	0	60	0
Amortization of net gain (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification, before tax	19	0	58	0
Net gain (loss) from hedging activities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before income taxes and noncontrolling interest	107	418	126	1,146
Tax (expense) benefit	(41)	(159)	(48)	(435)
Net loss	66	259	78	711
Net gain (loss) from hedging activities | Reclassification out of Accumulated Other Comprehensive Income | Interest rate caps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	13	(2)	22	(2)
Net gain (loss) from hedging activities | Reclassification out of Accumulated Other Comprehensive Income | Natural gas swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	$ 94	$ 420	$ 104	$ 1,148

Acquisitions - Allocation of Pu

Acquisitions - Allocation of Purchase Price (Details) - USD ($) $ in Thousands	Jun. 12, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Business Acquisition [Line Items]
Total consideration, net of cash acquired		$ 41,572	$ 1,777,740
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill		$ 1,306,547		$ 1,241,429
Sovitec Mondial S.A.
Business Acquisition [Line Items]
Total consideration, net of cash acquired	$ 41,572
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables	14,305
Inventories	7,645
Prepaid and other current assets	230
Property, plant and equipment	9,020
Other long-term assets	129
Fair value of assets acquired	31,329
Current debt	(6,420)
Accounts payable	(10,748)
Long-term debt	(10,189)
Other long-term liabilities	(154)
Fair value of net assets acquired	3,818
Goodwill	37,754
Net assets including goodwill acquired	$ 41,572

Acquisitions - Narratives (Deta

Acquisitions - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Acquisition costs	$ 966	$ 1,635	$ 5,295	$ 6,063
Nonrecurring charges			2,065
Sovitec Mondial S.A.
Business Acquisition [Line Items]
Net sales attributable to acquiree	13,490		17,194
Net income (loss) from acquiree	644		1,148
Acquisition costs	$ 737		$ 2,065

Acquisitions - Pro Forma Disclo

Acquisitions - Pro Forma Disclosure (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Combinations [Abstract]
Pro forma sales	$ 381,065	$ 1,130,454	$ 772,549
Pro forma net loss	$ (8,289)	$ (6,511)	$ (88,300)

Business Combination - Narrativ

Business Combination - Narratives (Details) - USD ($) $ in Thousands	May 04, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Equity consideration for the business combination				$ 0	$ 910,800
Acquisition costs		$ 966	$ 1,635	5,295	6,063
Net income (loss)		$ (3,016)	(9,606)	$ (7,001)	(89,685)
Debt Repayment Penalty
Business Acquisition [Line Items]
Net income (loss)					(26,250)
Refinancing Charges
Business Acquisition [Line Items]
Net income (loss)					(4,616)
Transaction Fees
Business Acquisition [Line Items]
Net income (loss)					(714)
PQ Holdings, Eco Services
Business Acquisition [Line Items]
Payments to acquire business	$ 1,777,740
Equity consideration for the business combination	910,800
Stock awards transfered as consideration	1,401
Net sales attributable to acquiree			276,726		462,097
Net income (loss) from acquiree			(29,070)		(122,497)
Acquisition costs			896		1,398
Increase to inventory at acquisition	$ 58,683
Cost of goods sold, additional portion related to step-up inventory price			$ 5,804		$ 23,518

Business Combination - Proforma

Business Combination - Proforma Disclosure (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition [Line Items]
Pro forma sales	$ 381,065	$ 1,130,454	$ 772,549
Pro forma net loss	$ (8,289)	$ (6,511)	(88,300)
PQ Holdings, Eco Services
Business Acquisition [Line Items]
Pro forma sales			1,080,310
Pro forma net loss			$ (55,985)

Goodwill (Details)

Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Goodwill
Beginning balance	$ 1,241,429
Goodwill recognized	37,754
Foreign exchange impact	27,364
Ending balance	1,306,547
Performance Materials & Chemicals
Goodwill
Beginning balance	852,506
Goodwill recognized	37,754
Foreign exchange impact	25,189
Ending balance	915,449
Environmental Catalysts & Services
Goodwill
Beginning balance	388,923
Goodwill recognized	0
Foreign exchange impact	2,175
Ending balance	$ 391,098

Other Operating Expense, Net (D

Other Operating Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income and Expenses [Abstract]
Restructuring and other related costs (Note 18)	$ 4,106	$ 1,336	$ 5,578	$ 10,898
Amortization expense	9,146	8,914	23,270	17,029
Net loss on asset disposals	3,494	627	6,419	2,288
Transaction and other related costs (1)	966	1,635	5,295	6,063
Management advisory fees	1,250	1,250	3,750	2,333
Other expense, net	871	1,280	2,844	2,019
Other operating expense, net	$ 19,833	$ 15,042	$ 47,156	$ 40,630

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Inventory, Net
Finished products and work in process	$ 178,844	$ 175,182
Raw materials	57,077	51,866
Inventory, Net	235,921	227,048
Valued at lower of cost or market:
LIFO basis	145,905	135,605
FIFO or average cost basis	90,016	91,443
Inventory, Net	$ 235,921	$ 227,048

Investments in Affiliated Com58

Investments in Affiliated Companies - Ownership Percentage (Details)	Sep. 30, 2017
PQ Silicates Ltd.
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Zeolyst International
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Zeolyst C.V.
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Quaker Holdings
Schedule of Equity Method Investments [Line Items]
Ownership percentage	49.00%

Investments in Affiliated Com59

Investments in Affiliated Companies - Summarized Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Equity Method Investment, Summarized Financial Information
Net sales	$ 83,983	$ 63,110	$ 225,770	$ 107,897
Gross profit	33,276	24,283	91,862	46,589
Operating income	22,713	15,054	60,408	30,708
Net income	$ 23,819	$ 15,351	$ 63,663	$ 30,994

Investments in Affiliated Com60

Investments in Affiliated Companies - Narratives (Details) - Business Combination - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Business Acquisition [Line Items]
Purchase accounting fair value adjustments			$ 266,358		$ 273,300
Equity method investment, amortization expense	$ 1,660	$ 12,291	$ 6,942	$ 24,606

Property, Plant and Equipment61

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,494,617	$ 1,336,584
Less: accumulated depreciation	(285,570)	(155,196)
Property, plant and equipment, net	1,209,047	1,181,388
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	191,917	186,327
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	191,916	157,944
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	955,779	788,175
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 155,005	$ 204,138

Property, Plant and Equipment -

Property, Plant and Equipment - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Depreciation	$ 31,957	$ 30,305	$ 89,987	$ 60,173

Long-term Debt (Details)

Long-term Debt (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Aug. 07, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Document Period End Date	Sep. 30, 2017
Total debt	$ 2,703,048		$ 2,617,970
Original issue discount	(26,470)		(28,497)
Deferred financing costs	(24,842)		(27,275)
Total debt, net of original issue discount and deferred financing costs	2,651,736		2,562,198
Less: current portion	(54,255)		(14,481)
Total long-term debt	2,597,481		2,547,717
Term Loan | Term Loan Facility | USD
Debt Instrument [Line Items]
Total debt	918,473	$ 927,750	925,430
Term Loan | Term Loan Facility | Euro
Debt Instrument [Line Items]
Total debt	331,368	$ 283,338	297,317
Senior Notes | 6.75% Senior Secured Notes due 2022
Debt Instrument [Line Items]
Total debt	$ 625,000		625,000
Debt instrument stated interest rate	6.75%
Senior Notes | Floating Rate Senior Unsecured Notes due 2022
Debt Instrument [Line Items]
Total debt	$ 525,000		525,000
Senior Notes | 8.5% Senior Notes due 2022
Debt Instrument [Line Items]
Total debt	$ 200,000		200,000
Debt instrument stated interest rate	8.50%
Line of Credit | ABL Facility
Debt Instrument [Line Items]
Total debt	$ 35,000		0
Other
Debt Instrument [Line Items]
Total debt	$ 68,207		$ 45,223

Long-term Debt - Narratives (De

Long-term Debt - Narratives (Details) - USD ($)	Oct. 03, 2017	Aug. 07, 2017	Jun. 22, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt, fair value difference from carrying value				$ 69,936,000		$ 68,477,000
Long-term debt				2,703,048,000		2,617,970,000
Repayments of long-term debt				10,289,000	$ 475,998,000
Cash paid for interest				118,793,000	$ 56,932,000
Senior Notes | Floating Rate Senior Unsecured Notes due 2022
Debt Instrument [Line Items]
Long-term debt				525,000,000		525,000,000
USB Investment Fund | New Markets Tax Credit Financing
Debt Instrument [Line Items]
Proceeds from contributions from affiliates			$ 3,054,000
Loans payable			6,221,000
Community Reinvestment Fund, Inc. | New Markets Tax Credit Financing
Debt Instrument [Line Items]
Proceeds from contributions from affiliates			9,000,000
Potters Industries, LLC | New Markets Tax Credit Financing
Debt Instrument [Line Items]
Loans payable			$ 8,820,000	8,820,000
USD | Term Loan | Term Loan Facility
Debt Instrument [Line Items]
Long-term debt		$ 927,750,000		918,473,000		925,430,000
USD | Term Loan | Term Loan Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate on spread		3.25%
Debt instrument, interest rate floor		0.00%
Euro | Term Loan | Term Loan Facility
Debt Instrument [Line Items]
Long-term debt		$ 283,338,000		331,368,000		$ 297,317,000
Euro | Term Loan | Term Loan Facility | EURIBOR
Debt Instrument [Line Items]
Variable rate on spread		3.25%
Debt instrument, interest rate floor		0.75%
Subsequent Event | Senior Notes | Floating Rate Senior Unsecured Notes due 2022
Debt Instrument [Line Items]
Repayments of long-term debt	$ 446,208,000
Debt instrument face amount	525,000,000
Cash paid for interest	2,693,000
Debt extinguishment costs	$ 32,284,000
Indemnification Agreement
Debt Instrument [Line Items]
Maximum indemnification liability				$ 3,682,000

Financial Instruments - Fair Va

Financial Instruments - Fair Value (Details) - Derivatives designated as cash flow hedges: - Cash Flow Hedging - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Asset derivatives:
Total asset derivatives	$ 1,098	$ 6,434
Liability derivatives:
Total liability derivatives	58	0
Current assets | Natural gas swaps
Asset derivatives:
Total asset derivatives	0	573
Current assets | Interest rate caps
Asset derivatives:
Total asset derivatives	9	0
Other long-term assets | Natural gas swaps
Asset derivatives:
Total asset derivatives	7	58
Other long-term assets | Interest rate caps
Asset derivatives:
Total asset derivatives	1,082	5,803
Accrued liabilities | Natural gas swaps
Liability derivatives:
Total liability derivatives	$ 58	$ 0

Financial Instruments - Effect

Financial Instruments - Effect on Other Comprehensive Income (Details) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Amount of gain (loss) recognized in OCI on derivatives (effective portion)
Amount of gain (loss) recognized in OCI on derivatives (effective portion)	$ (1,870)	$ (94)	$ (5,499)	$ (1,511)
Amount of gain (loss) reclassified from accumulated OCI into income (effective portion)
Amount of gain (loss) reclassified from accumulated OCI into income (effective portion)	107	418	126	1,146
Interest rate caps | Interest expense
Amount of gain (loss) recognized in OCI on derivatives (effective portion)
Amount of gain (loss) recognized in OCI on derivatives (effective portion)	(1,842)	212	(4,712)	212
Amount of gain (loss) reclassified from accumulated OCI into income (effective portion)
Amount of gain (loss) reclassified from accumulated OCI into income (effective portion)	13	(2)	22	(2)
Natural gas swaps | Cost of goods sold
Amount of gain (loss) recognized in OCI on derivatives (effective portion)
Amount of gain (loss) recognized in OCI on derivatives (effective portion)	(28)	(306)	(787)	(1,723)
Amount of gain (loss) reclassified from accumulated OCI into income (effective portion)
Amount of gain (loss) reclassified from accumulated OCI into income (effective portion)	$ 94	$ 420	$ 104	$ 1,148

Financial Instruments - Narrati

Financial Instruments - Narratives (Details)	1 Months Ended	9 Months Ended
	Jul. 31, 2016USD ($)	Sep. 30, 2017USD ($)MMBTU
Derivative [Line Items]
Derivative, notional quantity (in MMBTU) | MMBTU		690,000
Amount of derivative loss expected to be transfered from OCI		$ 241,000
Interest rate caps
Derivative [Line Items]
Premium paid to acquire derivative instrument	$ 1,551,000
Derivative, notional amount	$ 1,000,000
Interest rate caps | Minimum
Derivative [Line Items]
Derivative, cap interest rate	1.50%
Interest rate caps | Maximum
Derivative [Line Items]
Derivative, cap interest rate	3.00%

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	239.90%	26.90%	(304.20%)	(67.10%)

Benefit Plans - Net Periodic Pe

Benefit Plans - Net Periodic Pension Expense Benefit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Pension Plans | U.S.
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Service cost	$ 305	$ 547	$ 914	$ 1,640
Interest cost	2,536	2,522	7,608	5,236
Expected return on plan assets	(3,061)	(3,104)	(9,183)	(6,176)
Net periodic expense (benefit)	(220)	(35)	(661)	700
Defined Benefit Pension Plans | Foreign
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Service cost	859	792	2,642	1,320
Interest cost	1,339	837	4,024	1,396
Expected return on plan assets	(1,111)	(769)	(3,329)	(1,283)
Net periodic expense (benefit)	1,087	860	3,337	1,433
Supplemental Retirement Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Interest cost	123	121	370	202
Net periodic expense (benefit)	123	121	370	202
Other Postretirement Benefits Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Service cost	5	9	15	28
Interest cost	40	53	122	110
Amortization of prior service credit	(19)	0	(58)	0
Amortization of net gain	(19)	0	(58)	0
Net periodic expense (benefit)	$ 7	$ 62	$ 21	$ 138

Commitments and Contingent Li70

Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	1 Months Ended
	Sep. 30, 2017	Nov. 30, 2015	Dec. 31, 2016	Dec. 31, 2005
Asbestos Removal and Insulation Replacement
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 573		$ 532
Soil and Groundwater Contamination
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	839		913
Subsurface Remedial and Wetlands/Marsh Management
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	1,380		1,776
Subsurface Remediation and Soil Vapor Extraction
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	1,444		1,755
New Jersey Locations | PCB Remediation
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	557		700	$ 500
Chester And Baltimore Facilities | PCB Remediation
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	236		1,048
Pending Litigation | PADEP
Loss Contingencies [Line Items]
Value sought by counterparty	215	$ 1,739
Settlement amount awarded to counterparty		$ 1,550
Judicial Ruling | PADEP
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 215		$ 1,500

Reportable Segments - Summary

Reportable Segments - Summary Financial Information by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ 391,829	$ 369,979	$ 1,114,027	$ 741,446
Segment Adjusted EBITDA	96,835	78,668	271,037	125,567
Equity in net income (loss) from affiliated companies	10,257	(4,616)	24,879	(9,309)
Zeolyst Joint Venture
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	37,622	28,184	100,991	48,461
Segment Adjusted EBITDA	14,398	10,316	39,690	19,962
Equity in net income (loss) from affiliated companies	10,151	(4,683)	24,594	(9,213)
Investment in affiliate and inventory step-up amortization	1,658	12,291	6,941	24,606
Joint venture depreciation, amortization, and interest	2,563	2,690	8,073	4,534
Operating segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Segment Adjusted EBITDA	127,785	120,945	367,319	246,222
Operating segments | Performance Materials & Chemicals
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	277,072	256,219	765,781	429,867
Segment Adjusted EBITDA	65,885	64,604	184,741	111,178
Operating segments | Environmental Catalysts & Services
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	115,541	114,271	350,814	312,490
Segment Adjusted EBITDA	61,900	56,341	182,578	135,044
Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ (784)	$ (511)	$ (2,568)	$ (911)

Reportable Segments - Reconcil

Reportable Segments - Reconciliation of Net Loss to Adjusted EBITA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Net loss attributable to PQ Group Holdings Inc.	$ (3,345)	$ (10,017)	$ (7,408)	$ (90,410)
Provision for (benefit from) income taxes	5,172	(3,536)	5,269	36,013
Interest expense, net	49,079	48,610	144,041	94,362
Depreciation and amortization	45,929	43,611	129,135	85,602
Segment Adjusted EBITDA	96,835	78,668	271,037	125,567
Debt extinguishment costs	453	0	453	11,858
Losses on disposal of fixed assets	3,494	627	6,419	2,288
Foreign currency exchange loss			21,612	6,240
Management advisory fees	1,250	1,250	3,750	2,333
Transaction and other related costs (1)	966	1,635	5,295	6,063
Restructuring, integration and business optimization expenses			4,698
Corporate, non-segment
Segment Reporting Information [Line Items]
Unallocated corporate expenses	7,885	7,316	23,474	13,940
Segment reconciling items
Segment Reporting Information [Line Items]
Joint venture depreciation, amortization, and interest	2,563	2,690	8,073	4,534
Investment in affiliate and inventory step-up amortization	1,660	12,291	6,942	24,606
Amortization of inventory step-up	0	5,804	871	23,518
Debt extinguishment costs	453	0	453	11,858
Losses on disposal of fixed assets	3,494	627	6,419	2,288
Foreign currency exchange loss	5,256	3,151	21,612	6,240
Non-cash revaluation of inventory, including LIFO	750	329	3,229	775
Management advisory fees	1,250	1,250	3,750	2,333
Transaction and other related costs (1)	966	1,696	5,300	6,240
Equity-based and other non-cash compensation	1,041	1,137	3,869	4,916
Restructuring, integration and business optimization expenses	4,957	2,839	8,009	14,567
Defined benefit pension plan cost	791	1,244	2,200	2,642
Other expense, net	(116)	1,903	2,081	2,198
Operating segments
Segment Reporting Information [Line Items]
Segment Adjusted EBITDA	$ 127,785	$ 120,945	$ 367,319	$ 246,222

Restructuring and Other Relat73

Restructuring and Other Related Costs - Components of Restructuring and Other Related Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs	$ 4,106	$ 1,336	$ 5,578	$ 10,898
Minimum
Restructuring Cost and Reserve [Line Items]
Estimated remaining restructuring costs	500		500
Maximum
Restructuring Cost and Reserve [Line Items]
Estimated remaining restructuring costs	1,000		1,000
Other related costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs	238	1,336	880	6,402
Legacy Eco Restructuring Plan | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs	0	0	830	4,496
Performance Materials Plant Closure | Severance and other employee costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other related costs	$ 3,868	$ 0	$ 3,868	$ 0

Restructuring and Other Relat74

Restructuring and Other Related Costs - Schedule of Restructuring Reserve (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Restructuring Reserve [Roll Forward]
Beginning balance	$ 1,643
Restructuring charges	4,698
Cash payments	(1,971)
Ending balance	4,370
Legacy Eco Restructuring Plan
Restructuring Reserve [Roll Forward]
Beginning balance	1,643
Restructuring charges	830
Cash payments	(1,971)
Ending balance	502
Performance Materials Plant Closure
Restructuring Reserve [Roll Forward]
Beginning balance	0
Restructuring charges	3,868
Cash payments	0
Ending balance	$ 3,868

Earnings per Share - Reconcilia

Earnings per Share - Reconciliation from Basic to Diluted Weighted Average Shares Outstanding (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Weighted average shares outstanding – Basic (shares)	104,096,837	103,783,719	104,020,180	81,986,221
Dilutive effect of unvested common shares with service conditions and assumed stock option exercises and conversions (shares)	0	0	0	0
Weighted average shares outstanding – Diluted (shares)	104,096,837	103,783,719	104,020,180	81,986,221

Earnings per Share - Reconcil76

Earnings per Share - Reconciliation of Net Income (Loss) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income (loss) attributable to PQ Group Holdings Inc.	$ (3,345)	$ (10,017)	$ (7,408)	$ (90,410)
Denominator:
Weighted average shares outstanding – Basic (shares)	104,096,837	103,783,719	104,020,180	81,986,221
Weighted average shares outstanding – Diluted (shares)	104,096,837	103,783,719	104,020,180	81,986,221
Net loss per common share:
Basic net loss per share (usd per share)	$ (0.03)	$ (0.10)	$ (0.07)	$ (1.10)
Diluted net loss per share (usd per share)	$ (0.03)	$ (0.10)	$ (0.07)	$ (1.10)

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - USD ($) $ / shares in Units, $ in Thousands	Oct. 03, 2017	Oct. 02, 2017
Subsequent Event [Line Items]
Stock options granted (in shares)		621,747
IPO
Subsequent Event [Line Items]
Price of shares issued (usd per share)	$ 17.50
Shares issued (shares)	29,000,000
Proceeds from initial public offering	$ 480,525
Restricted Stock Units
Subsequent Event [Line Items]
Equity instruments other than options, grants in period (in shares)		1,654,685
Stock Awards
Subsequent Event [Line Items]
Equity instruments other than options, grants in period (in shares)		21,067