Ecovyst (ECVT) 10-Q 5 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-38221
Entity Registrant Name	PQ Group Holdings Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3406833
Entity Address, Address Line One	300 Lindenwood Drive
Entity Address, City or Town	Malvern,
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19355
City Area Code	(610)
Local Phone Number	651-4400
Trading Symbol	PQG
Title of 12(b) Security	Common stock, par value $0.01 per share
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		136,474,348
Entity Central Index Key	0001708035
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Sales	$ 423,801	$ 427,203	$ 1,214,697	$ 1,228,113
Cost of goods sold	310,904	319,703	905,395	934,088
Gross profit	112,897	107,500	309,302	294,025
Selling, general and administrative expenses	39,528	42,145	123,611	126,240
Other operating expense, net	15,795	16,501	28,353	41,688
Operating income	57,574	48,854	157,338	126,097
Equity in net (income) from affiliated companies	(17,261)	(5,605)	(31,625)	(31,123)
Interest expense, net	27,697	28,238	84,855	84,622
Debt extinguishment costs	1,767	864	1,767	6,743
Other expense, net	1,834	2,451	1,890	13,114
Income before income taxes and noncontrolling interest	43,537	22,906	100,451	52,741
Provision for income taxes	16,718	8,470	39,472	21,590
Net income	26,819	14,436	60,979	31,151
Less: Net income attributable to the noncontrolling interest	106	251	541	970
Net income attributable to PQ Group Holdings Inc.	$ 26,713	$ 14,185	$ 60,438	$ 30,181
Net income per share:
Basic income per share (usd per share)	$ 0.20	$ 0.11	$ 0.45	$ 0.23
Diluted income per share (usd per share)	$ 0.20	$ 0.11	$ 0.45	$ 0.22
Weighted average shares outstanding:
Basic (shares)	134,511,819	133,336,352	134,213,571	133,237,653
Diluted (shares)	135,649,710	134,576,162	135,305,370	134,223,628

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 26,819	$ 14,436	$ 60,979	$ 31,151
Other comprehensive income (loss), net of tax:
Pension and postretirement benefits	(59)	(52)	(120)	1,305
Net (loss) gain from hedging activities	35	370	(2,684)	3,106
Foreign currency translation	(13,872)	5,186	(620)	(15,636)
Total other comprehensive income (loss)	(13,896)	5,504	(3,424)	(11,225)
Comprehensive income	12,923	19,940	57,555	19,926
Less: Comprehensive income (loss) attributable to noncontrolling interests	(304)	1,218	586	1,697
Comprehensive income attributable to PQ Group Holdings Inc.	$ 13,227	$ 18,722	$ 56,969	$ 18,229

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 78,510	$ 57,854
Accounts receivable, net	214,626	196,770
Inventories, net	259,766	264,748
Prepaid and other current assets	39,055	39,244
Total current assets	591,957	558,616
Investments in affiliated companies	477,144	468,211
Property, plant and equipment, net	1,178,479	1,208,979
Goodwill	1,251,296	1,254,929
Other intangible assets, net	683,296	728,436
Right-of-use lease assets	54,238	0
Other long-term assets	129,069	108,254
Total assets	4,365,479	4,327,425
LIABILITIES
Notes payable and current maturities of long-term debt	8,210	7,237
Accounts payable	132,096	148,365
Operating lease liabilities—current	14,095	0
Accrued liabilities	108,365	100,009
Total current liabilities	262,766	255,611
Long-term debt, excluding current portion	2,006,717	2,106,720
Deferred income taxes	214,935	196,124
Operating lease liabilities—noncurrent	38,473	0
Other long-term liabilities	105,927	104,825
Total liabilities	2,628,818	2,663,280
Commitments and contingencies (Note 17)
EQUITY
Common stock ($0.01 par); authorized shares 450,000,000; issued shares 136,469,863 and 135,758,269 on September 30, 2019 and December 31, 2018, respectively; outstanding shares 136,157,186 and 135,592,045 on September 30, 2019 and December 31, 2018, respectively	1,365	1,358
Preferred stock ($0.01 par); authorized shares 50,000,000; no shares issued or outstanding on September 30, 2019 and December 31, 2018	0	0
Additional paid-in capital	1,692,223	1,674,703
Retained earnings	83,912	25,523
Treasury stock, at cost; shares 312,677 and 166,224 on September 30, 2019 and December 31, 2018, respectively	(5,155)	(2,920)
Accumulated other comprehensive loss	(40,699)	(39,104)
Total PQ Group Holdings Inc. equity	1,731,646	1,659,560
Noncontrolling interest	5,015	4,585
Total equity	1,736,661	1,664,145
Total liabilities and equity	$ 4,365,479	$ 4,327,425

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
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)	136,469,863	135,758,269
Common stock, shares outstanding (shares)	136,157,186	135,592,045
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)	312,677	166,224

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Treasury stock, at cost	Accumulated other comprehensive income (loss)	Non- controlling interest
Beginning balance at Dec. 31, 2017	$ 1,631,919	$ 1,352	$ 1,655,114	$ (32,777)	$ 0	$ 4,311	$ 3,919
Increase (Decrease) in Stockholders' Equity
Net income	556			214			342
Other comprehensive income	10,836					9,532	1,304
Repurchases of common shares	(58)				(58)
Stock compensation expense	3,831		3,831
Ending balance at Mar. 31, 2018	1,647,084	1,352	1,658,945	(32,563)	(58)	13,843	5,565
Beginning balance at Dec. 31, 2017	1,631,919	1,352	1,655,114	(32,777)	0	4,311	3,919
Increase (Decrease) in Stockholders' Equity
Net income	31,151
Other comprehensive income	(11,225)
Ending balance at Sep. 30, 2018	1,662,473	1,352	1,667,036	(2,596)	(768)	(7,641)	5,090
Beginning balance at Mar. 31, 2018	1,647,084	1,352	1,658,945	(32,563)	(58)	13,843	5,565
Increase (Decrease) in Stockholders' Equity
Net income	16,159			15,782			377
Other comprehensive income	(27,565)					(26,021)	(1,544)
Distributions to noncontrolling interests	(153)						(153)
Stock compensation expense	3,796		3,796
Shares issued under equity incentive plan, net of forfeitures	7	0	7
Ending balance at Jun. 30, 2018	1,639,328	1,352	1,662,748	(16,781)	(58)	(12,178)	4,245
Increase (Decrease) in Stockholders' Equity
Net income	14,436			14,185			251
Other comprehensive income	5,504					4,537	967
Repurchases of common shares	(710)				(710)
Distributions to noncontrolling interests	(373)						(373)
Stock compensation expense	4,252		4,252
Shares issued under equity incentive plan, net of forfeitures	36	0	36
Ending balance at Sep. 30, 2018	1,662,473	1,352	1,667,036	(2,596)	(768)	(7,641)	5,090
Increase (Decrease) in Stockholders' Equity
Beginning balance, adjusted	1,663,970	1,358	1,674,703	23,474	(2,920)	(37,230)	4,585
Cumulative effect adjustment from adoption of new accounting standards | Accounting Standards Updates 2016-02 and 2018-02	(175)			(2,049)		1,874
Beginning balance at Dec. 31, 2018	1,664,145	1,358	1,674,703	25,523	(2,920)	(39,104)	4,585
Increase (Decrease) in Stockholders' Equity
Net income	3,441			3,151			290
Other comprehensive income	5,585					5,270	315
Repurchases of common shares	(1,339)				(1,339)
Stock compensation expense	3,400		3,400
Shares issued under equity incentive plan, net of forfeitures	215	2	213
Ending balance at Mar. 31, 2019	1,675,272	1,360	1,678,316	26,625	(4,259)	(31,960)	5,190
Beginning balance at Dec. 31, 2018	1,664,145	1,358	1,674,703	25,523	(2,920)	(39,104)	4,585
Increase (Decrease) in Stockholders' Equity
Net income	60,979
Other comprehensive income	(3,424)
Ending balance at Sep. 30, 2019	1,736,661	1,365	1,692,223	83,912	(5,155)	(40,699)	5,015
Beginning balance at Mar. 31, 2019	1,675,272	1,360	1,678,316	26,625	(4,259)	(31,960)	5,190
Increase (Decrease) in Stockholders' Equity
Net income	30,719			30,574			145
Other comprehensive income	4,887					4,747	140
Distributions to noncontrolling interests	(156)						(156)
Stock compensation expense	5,370		5,370
Shares issued under equity incentive plan, net of forfeitures	3,260	4	3,256
Ending balance at Jun. 30, 2019	1,719,352	1,364	1,686,942	57,199	(4,259)	(27,213)	5,319
Increase (Decrease) in Stockholders' Equity
Net income	26,819			26,713			106
Other comprehensive income	(13,896)					(13,486)	(410)
Repurchases of common shares	(896)				(896)
Stock compensation expense	4,806		4,806
Shares issued under equity incentive plan, net of forfeitures	476	1	475
Ending balance at Sep. 30, 2019	$ 1,736,661	$ 1,365	$ 1,692,223	$ 83,912	$ (5,155)	$ (40,699)	$ 5,015

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 60,979	$ 31,151
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	97,088	99,491
Amortization	38,142	39,807
Amortization of inventory step-up	0	1,603
Amortization of deferred financing costs and original issue discount	4,352	4,629
Debt extinguishment costs	1,767	4,619
Foreign currency exchange loss	5,380	15,347
Pension and postretirement healthcare benefit expense	2,731	347
Pension and postretirement healthcare benefit funding	(8,917)	(6,415)
Deferred income tax provision	16,822	1,494
Net (gain) loss on asset disposals	(7,697)	11,106
Stock compensation	13,576	11,879
Equity in net (income) from affiliated companies	(31,625)	(31,123)
Dividends received from affiliated companies	20,072	35,890
Net interest income on swaps designated as net investment hedges	(8,435)	(4,279)
Other, net	(887)	(6,473)
Working capital changes that provided (used) cash, excluding the effect of acquisitions and dispositions:
Receivables	(22,472)	(43,106)
Inventories	(1,793)	8,778
Prepaids and other current assets	268	(1,555)
Accounts payable	(4,072)	(7,594)
Accrued liabilities	6,615	407
Net cash provided by operating activities	181,894	166,003
Cash flows from investing activities:
Purchases of property, plant and equipment	(91,653)	(95,322)
Payments to Acquire Equity Method Investments	0	5,000
Business combinations, net of cash acquired	0	(1,006)
Proceeds from sale of product line	28,000	0
Net interest proceeds on swaps designated as net investment hedges	8,435	4,279
Other, net	475	1,142
Net cash used in investing activities	(54,743)	(95,907)
Cash flows from financing activities:
Draw down of revolving credit facilities	161,630	139,577
Repayments of revolving credit facilities	(160,342)	(163,103)
Issuance of long-term debt	0	1,267,000
Debt issuance costs	0	(6,156)
Repayments of long-term debt	(105,821)	(1,313,832)
Stock repurchases	(2,235)	(768)
Distributions to noncontrolling interests	156	526
Proceeds from stock options exercised	3,956	43
Other, net	(283)	0
Net cash used in financing activities	(103,251)	(77,765)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(3,371)	(1,557)
Net change in cash, cash equivalents and restricted cash	20,529	(9,226)
Cash, cash equivalents and restricted cash at beginning of period	59,726	67,243
Cash, cash equivalents and restricted cash at end of period	$ 80,255	$ 58,017

Background and Basis of Present

Background and Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis of Presentation	1. Background and Basis of Presentation: Description of Business PQ Group Holdings Inc. and subsidiaries (the “Company” or “PQ Group Holdings”) is a leading integrated and innovative global provider of specialty catalysts, materials, chemicals and services. The Company supports customers globally through its strategically located network of manufacturing facilities. The Company believes that its products, which are predominantly inorganic, and services contribute to improving the sustainability of the environment. The Company has four uniquely positioned specialty businesses: Refining Services provides sulfuric acid recycling to the North American refining industry; Catalysts serves the packaging and engineered plastics and the global refining, petrochemical and emissions control industries; Performance Materials produces transportation reflective safety markings for roads and airports; and Performance Chemicals supplies diverse product end uses, including personal and industrial cleaning products, fuel-efficient tires, surface coatings, and food and beverage products. Effective March 1, 2019, the Company changed the structure of its internal organization to create the four independent businesses described above in order to promote increased visibility to business unit performance, optimize the Company’s product portfolio and create efficiencies. Previously, the Company had two reportable segments, namely the Environmental Catalysts and Services segment and the Performance Materials and Chemicals segment. Beginning with the quarter ended March 31, 2019, the segment results and disclosures included in the Company’s consolidated financial statements reflect the new segment structure for all periods presented. The changes to the Company’s segment structure affect only the manner in which the results of the Company’s reportable segments were previously reported; there are no changes to the Company’s consolidated balance sheet, statement of income or cash flows for the prior periods. For the purposes of the Company’s goodwill impairment testing, the four new operating segments align with the Company’s reporting units at which level goodwill has been assigned and historically tested for impairment. Seasonal changes and weather conditions typically affect the Company’s Performance Materials and Refining Services segments. In particular, the Company’s Performance Materials segment generally experiences lower sales and profit in the first and fourth quarters of the year because highway striping projects typically occur during warmer weather months. Additionally, the Company’s Refining Services segment 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 second quarters of the year, which can adversely affect the Company’s liquidity and cash flows. Because of this seasonality associated with certain of the Company’s segments, results for any one quarter are not necessarily indicative of the results that may be achieved for any other quarter or for the full year. Basis of Presentation The condensed consolidated financial statements included herein are unaudited. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (“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 Annual Report on Form 10-K for the year ended December 31, 2018 . Other than the update to our lease accounting policies described in Note 12 , the Company has continued to follow the accounting policies set forth in those consolidated financial statements.

New Accounting Standards

New Accounting Standards	9 Months Ended
	Sep. 30, 2019
New Accounting Standards [Abstract]
New Accounting Standards	2. New Accounting Standards: Recently Adopted Accounting Standards In February 2016, the Financial Accounting Standards Board (“FASB”) issued guidance (with subsequent targeted amendments) that modifies the accounting for leases. Under the new guidance, a lessee recognizes right-of-use lease assets and lease liabilities for most leases (including those classified under existing GAAP as operating leases, which based on previous standards are not reflected on the balance sheet), but recognizes expenses in a manner that is generally consistent with existing practices. The new guidance also requires companies to provide expanded disclosures regarding leasing arrangements. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. The new guidance must be adopted using a modified retrospective transition method. The Company adopted the new lease guidance effective January 1, 2019 as required using the modified retrospective transition method and applied the provisions of the guidance at the effective date with a cumulative-effect adjustment to the opening balance of retained earnings without adjusting the comparative periods presented. The new guidance provides practical expedients and allows for certain policy elections with regard to the Company’s lease population. The Company has elected the short term lease accounting policy and will not record right-of-use lease assets or lease liabilities for leases with an initial term of twelve months or less. Additionally, the Company has elected to utilize the portfolio approach to apply incremental borrowing rates to its leases. The Company has elected the package of practical expedients which provides the Company with the ability to bypass reassessment of the following for leases existing at the date of adoption: (1) whether any existing contracts are, or contain, leases; (2) the lease classification for any existing leases; and (3) initial direct costs for any existing leases. The Company also elected the land easement practical expedient to carry forward existing accounting treatment on existing land easements. Adoption of the new lease guidance resulted in the recognition of right-of-use lease assets of $60,726 , which included $57,832 of right-of-use lease assets related to lease commitments and $2,895 related to the reclassification of favorable lease contracts, and lease liabilities of $58,929 . The new guidance had no impact on the Company’s operating results or liquidity upon adoption. Disclosures related to the Company’s leases are included in Note 12 to these condensed consolidated financial statements. In February 2018, the FASB issued guidance which permits entities to make a one-time election to reclassify the residual (“stranded”) income tax effects included in accumulated other comprehensive income (“AOCI”) to beginning retained earnings as a result of tax reform legislation enacted by the U.S. government on December 22, 2017, namely the Tax Cuts and Jobs Act of 2017 (“TCJA”). The standard is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. Prior to the enactment of the tax reform legislation on December 22, 2017, the Company had amounts recorded in AOCI related to its domestic pension, postretirement and supplementary benefit plans and cash flow hedging relationships that were based on pre-enactment tax rates, which were included in AOCI at the adoption date of the new guidance. The Company adopted the new guidance effective January 1, 2019 as required, and elected to reclassify the income tax effects stranded in AOCI related to the change in the U.S. federal corporate income tax rate from the TCJA of $1,874 from AOCI to beginning retained earnings. There were no other income tax effects related to the application of the TCJA that were included in this reclassification. The Company’s accounting policy for releasing income tax effects from AOCI is based on individual units of account. In June 2018, the FASB issued guidance which conforms the accounting for the issuance of all share-based payments using the same accounting model. Previously, the accounting for share-based payments to non-employees was covered under a different framework than those made to employees. Under the new guidance, awards to both employees and non-employees essentially follow the same model, with small variations related to determining the term assumption when valuing a non-employee award as well as a different expense attribution model for non-employee awards. The new guidance is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The Company adopted the new guidance on January 1, 2019 as required, with no material impact on its consolidated financial statements upon adoption. Accounting Standards Not Yet Adopted In August 2018, the FASB issued guidance which modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The guidance eliminates certain disclosure requirements, including the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next fiscal year and the effects of a one-percentage point change in assumed health care cost trend rates. The guidance also requires additional disclosure of the reasons for significant gains and losses related to changes in the benefit obligation for the period. The guidance is effective for fiscal years ending after December 15, 2020 with early adoption permitted, and is required to be applied on a retrospective basis to all periods presented. The Company will modify its benefit plan disclosures in accordance with the new guidance upon adoption, and the Company believes that the new guidance will not have a material impact on its consolidated financial statements. In August 2018, the FASB issued guidance which modifies certain disclosure requirements over fair value measurements. The guidance is effective for fiscal years beginning after December 15, 2019, including all interim periods within that fiscal year. The Company believes that the new guidance will not have a material impact 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 Securities and Exchange Commission (“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. The Company will apply the guidance to its goodwill impairment tests upon the required adoption date or earlier as permitted. In June 2016, the FASB issued guidance (with subsequent targeted amendments) that affects loans, trade receivables and any other financial assets that have the contractual right to receive cash. Under the new guidance, an entity is required to recognize expected credit losses rather than incurred losses for financial assets. The new guidance is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. The Company believes that the new guidance will not have a material impact on its consolidated financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	3. Revenue from Contracts with Customers: Disaggregated Revenue The Company’s primary means of disaggregating revenues is by reportable segments, which can be found in Note 18 to these condensed consolidated financial statements. The Company’s portfolio of products are integrated into a variety of end uses, which are described in the table below. Key End Uses Key Products Industrial & process chemicals • Silicate precursors for the tire industry • Glass beads, or microspheres, for metal finishing end uses Fuels & emission control • Refinery catalysts • Emission control catalysts • Catalyst recycling services • Silicate for catalyst manufacturing Packaging & engineered plastics • Catalysts for high-density polyethlene and chemicals syntheses • Antiblocks for film packaging • Solid and hollow microspheres for composite plastics • Sulfur derivatives for nylon production Highway safety & construction • Reflective markings for roadways and airports • Silica gels for surface coatings Consumer products • Silica gels for edible oil and beer clarification • Precipitated silicas, silicates and zeolites for the dentifrice and dishwasher and laundry detergent applications Natural resources • Silicates for drilling muds • Hollow glass beads, or microspheres, for oil well cements • Silicates and alum for water treatment mining • Bleaching aids for paper The following tables disaggregate the Company’s sales, by segment and end use, for the three and nine months ended September 30, 2019 and 2018 : Three months ended September 30, 2019 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 20,180 $ 47 $ 12,225 $ 54,696 $ 87,148 Fuels & emission control (1) 70,048 — — — 70,048 Packaging & engineered plastics 12,197 25,565 16,886 12,048 66,696 Highway safety & construction (1) — — 82,502 20,800 103,302 Consumer products — — — 64,849 64,849 Natural resources 15,910 — 3,521 15,556 34,987 Total segment sales 118,335 25,612 115,134 167,949 427,030 Eliminations (813 ) (47 ) (18 ) (2,351 ) (3,229 ) Total $ 117,522 $ 25,565 $ 115,116 $ 165,598 $ 423,801 Nine months ended September 30, 2019 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 60,485 $ 109 $ 38,037 $ 175,009 $ 273,640 Fuels & emission control (1) 191,243 — — — 191,243 Packaging & engineered plastics 38,953 62,226 51,863 41,121 194,163 Highway safety & construction (1) — — 195,119 65,036 260,155 Consumer products — — — 198,798 198,798 Natural resources 50,788 — 10,076 46,275 107,139 Total segment sales 341,469 62,335 295,095 526,239 1,225,138 Eliminations (2,595 ) (109 ) (170 ) (7,567 ) (10,441 ) Total $ 338,874 $ 62,226 $ 294,925 $ 518,672 $ 1,214,697 Three months ended September 30, 2018 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 21,027 $ — $ 11,263 $ 55,589 $ 87,879 Fuels & emission control (1) 66,095 — — — 66,095 Packaging & engineered plastics 16,636 16,347 17,763 14,086 64,832 Highway safety & construction (1) — — 82,738 22,466 105,204 Consumer products — — — 67,138 67,138 Natural resources 19,611 — 3,616 15,443 38,670 Total segment sales 123,369 16,347 115,380 174,722 429,818 Eliminations (833 ) — 119 (1,901 ) (2,615 ) Total $ 122,536 $ 16,347 $ 115,499 $ 172,821 $ 427,203 Nine months ended September 30, 2018 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 55,347 $ 54 $ 38,070 $ 186,886 $ 280,357 Fuels & emission control (1) 182,304 — — — 182,304 Packaging & engineered plastics 45,032 50,113 57,247 40,375 192,767 Highway safety & construction (1) — — 198,165 64,930 263,095 Consumer products — — — 209,256 209,256 Natural resources 53,471 — 11,178 46,999 111,648 Total segment sales 336,154 50,167 304,660 548,446 1,239,427 Eliminations (2,456 ) (54 ) (214 ) (8,590 ) (11,314 ) Total $ 333,698 $ 50,113 $ 304,446 $ 539,856 $ 1,228,113 (1) As described in Note 1 , the Company experiences seasonal sales fluctuations to customers in the fuels & emission control and highway safety & construction end uses. Contract Assets and Liabilities A contract asset is a right to consideration in exchange for goods that the Company has transferred to a customer when that right is conditional on something other than the passage of time. A contract liability exists when the Company receives consideration in advance of performance obligations. The Company has not recorded any contract assets on its condensed consolidated balance sheets as of September 30, 2019 and December 31, 2018 , and no contract liabilities existed as of December 31, 2018 . The Company recognized a $9,000 contract liability associated with the sale of a portion of its sulfate salts product line, of which $7,965 of deferred revenue remained as of September 30, 2019 . The Company recognized revenue of $1,035 related to this contract liability during the three and nine months ended September 30, 2019 . Refer to Note 6

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. 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, 2019 and December 31, 2018 , and indicates the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. September 30, Quoted Prices in Significant Other Observable Inputs (Level 2) Significant Assets: Derivative contracts (Note 14) $ 40,125 $ — $ 40,125 $ — Restoration plan assets 4,238 4,238 — — Total $ 44,363 $ 4,238 $ 40,125 $ — Liabilities: Derivative contracts (Note 14) $ 4,130 $ — $ 4,130 $ — December 31, Quoted Prices in Significant Other Observable Inputs (Level 2) Significant Assets: Derivative contracts (Note 14) $ 20,768 $ — $ 20,768 $ — Restoration plan assets 4,244 4,244 — — Total $ 25,012 $ 4,244 $ 20,768 $ — Liabilities: Derivative contracts (Note 14) $ 2,026 $ — $ 2,026 $ — 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 16 to these condensed consolidated financial statements regarding defined supplementary retirement plans. The Company’s restoration plan assets are included in other long-term assets on its condensed consolidated balance sheets. Gains and losses related to these investments are included in other expense, net in the Company’s condensed consolidated statements of income. Unrealized gains and losses associated with the underlying stock and fixed income mutual funds were immaterial as of September 30, 2019 and December 31, 2018 , respectively. 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.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Accumulated Other Comprehensive Income	5. Accumulated Other Comprehensive Income: The following tables present the tax effects of each component of other comprehensive income for the three and nine months ended September 30, 2019 and 2018 : Three months ended September 30, 2019 2018 Pre-tax amount Tax benefit/(expense) After-tax amount Pre-tax amount Tax benefit/(expense) After-tax amount Defined benefit and other postretirement plans: Amortization of net gains and (losses) $ (10 ) $ 4 $ (6 ) $ (50 ) $ 13 $ (37 ) Amortization of prior service cost (63 ) 10 (53 ) (19 ) 4 (15 ) Benefit plans, net (73 ) 14 (59 ) (69 ) 17 (52 ) Net (loss) gain from hedging activities 46 (11 ) 35 494 (124 ) 370 Foreign currency translation (1) (10,020 ) (3,852 ) (13,872 ) 3,391 1,795 5,186 Other comprehensive income (loss) $ (10,047 ) $ (3,849 ) $ (13,896 ) $ 3,816 $ 1,688 $ 5,504 Nine months ended September 30, 2019 2018 Pre-tax amount Tax benefit/(expense) After-tax amount Pre-tax amount Tax benefit/(expense) After-tax amount Defined benefit and other postretirement plans: Amortization of net gains and (losses) $ (26 ) $ 8 $ (18 ) $ 1,798 $ (449 ) $ 1,349 Amortization of prior service cost (128 ) 26 (102 ) (58 ) 14 (44 ) Benefit plans, net (154 ) 34 (120 ) 1,740 (435 ) 1,305 Net (loss) gain from hedging activities (3,579 ) 895 (2,684 ) 4,143 (1,037 ) 3,106 Foreign currency translation (1) 4,731 (5,351 ) (620 ) (16,442 ) 806 (15,636 ) Other comprehensive income (loss) $ 998 $ (4,422 ) $ (3,424 ) $ (10,559 ) $ (666 ) $ (11,225 ) (1) The income tax benefit or expense included in other comprehensive income is attributed to the portion of foreign currency translation associated with the Company’s cross-currency interest rate swaps, for which the tax effect is based on the applicable U.S. deferred income tax rate. See Note 14 to these condensed consolidated financial statements for information regarding the Company’s cross-currency interest rate swaps. The following table presents the changes in accumulated other comprehensive income (loss), net of tax, by component for the nine months ended September 30, 2019 and 2018 : Defined benefit Net gain (loss) from hedging activities Foreign Total December 31, 2018 $ (546 ) $ 637 $ (39,195 ) $ (39,104 ) Other comprehensive loss before reclassifications (27 ) (3,163 ) (665 ) (3,855 ) Amounts reclassified from accumulated other comprehensive income (1) (93 ) 479 — 386 Net current period other comprehensive loss (120 ) (2,684 ) (665 ) (3,469 ) Tax Cuts and Jobs Act, reclassification from AOCI to retained earnings 1,684 190 — 1,874 September 30, 2019 $ 1,018 $ (1,857 ) $ (39,860 ) $ (40,699 ) December 31, 2017 $ 7,412 $ 967 $ (4,068 ) $ 4,311 Other comprehensive income (loss) before reclassifications 1,360 2,906 (16,363 ) (12,097 ) Amounts reclassified from accumulated other comprehensive income (1) (55 ) 200 — 145 Net current period other comprehensive income (loss) 1,305 3,106 (16,363 ) (11,952 ) September 30, 2018 $ 8,717 $ 4,073 $ (20,431 ) $ (7,641 ) (1) See the following table for details about these reclassifications. Amounts in parentheses indicate debits. The following table presents the reclassifications out of accumulated other comprehensive income for the three and nine months ended September 30, 2019 and 2018 : Details about Accumulated Other Comprehensive Income Components Amounts Reclassified from Accumulated Other Comprehensive Income(1) Affected Line Item where Income is Presented Three months ended Nine months ended 2019 2018 2019 2018 Amortization of defined benefit and other postretirement items: Prior service credit (cost) $ 32 $ 40 $ 97 $ 79 Other income (expense) (2) Actuarial gains (losses) 8 (2 ) 26 (5 ) Other income (expense) (2) 40 38 123 74 Total before tax (10 ) (13 ) (30 ) (19 ) Tax expense $ 30 $ 25 $ 93 $ 55 Net of tax Gains and losses on cash flow hedges: Interest rate caps $ (157 ) $ (71 ) $ (449 ) $ (164 ) Interest expense Natural gas swaps (291 ) (30 ) (187 ) (101 ) Cost of goods sold (448 ) (101 ) (636 ) (265 ) Total before tax 111 24 157 65 Tax benefit $ (337 ) $ (77 ) $ (479 ) $ (200 ) Net of tax Total reclassifications for the period $ (307 ) $ (52 ) $ (386 ) $ (145 ) Net of tax (1) Amounts in parentheses indicate debits to profit/loss. (2) These accumulated other comprehensive income (loss) components are components of net periodic pension and other postretirement cost (see Note 16 to these condensed consolidated financial statements for additional details).

Sale of Product Line

Sale of Product Line	9 Months Ended
	Sep. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Sale of product line	6. Sale of Product Line: On June 28, 2019 , the Company completed the sale of a portion of its sulfate salts product line within its Performance Chemicals segment for $28,000 and recorded a pre-tax gain on sale of $11,362 . The transaction was recorded as an asset sale, with the gain on disposition included in the other operating expense, net line item in the Company’s condensed consolidated statement of income for the nine months ended September 30, 2019 (see Note 8 to these condensed consolidated financial statements for additional details). At the time of disposition, the carrying value of the Company’s net working capital related to this non-core product line was $4,215 . In addition to the net working capital sold as part of the transaction, the Company also derecognized $3,423 of property, plant and equipment related to the product line and allocated $9,000 of the consideration received to a liability for deferred revenue. Concurrent with the product line sale, the Company entered into a tolling arrangement with the buyer in which the Company will use its existing manufacturing facilities for the product line to manufacture the product for the buyer, the majority of which runs until June 2021. The Company deferred $9,000 of the $28,000 consideration received as a liability, to be recognized as the Company executes its performance obligations over the term of the contractual agreement with the buyer. Additionally, the Company concluded that an embedded lease arrangement exists as a result of the combination of the sale and tolling agreements. Given the ability of the buyer to control substantially all of the output of the facilities and the existence of bargain purchase options on the manufacturing assets, the Company determined that the buyer is effectively leasing the assets from the Company and derecognized the associated property, plant and equipment under a sales-type leasing arrangement. The gain on the sale of fixed assets is included as part of the Company’s overall gain on sale related to the transaction, with the Company’s net investment in the leased assets having been settled as part of the consideration received in the transaction with no additional future cash flows to be recognized on the lease.

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	7. Goodwill: The change in the carrying amount of goodwill for the nine months ended September 30, 2019 is summarized as follows: Refining Services Catalysts Performance Materials Performance Chemicals Total Balance as of December 31, 2018 $ 311,892 $ 77,759 $ 274,947 $ 590,331 $ 1,254,929 Foreign exchange impact — (844 ) 458 (3,247 ) (3,633 ) Balance as of September 30, 2019 $ 311,892 $ 76,915 $ 275,405 $ 587,084 $ 1,251,296

Other Operating Expense, Net

Other Operating Expense, Net	9 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Other Operating Expense, Net	8. Other Operating Expense, Net: A summary of other operating expense, net is as follows: Three months ended Nine months ended 2019 2018 2019 2018 Amortization expense $ 8,607 $ 8,711 $ 25,907 $ 26,404 Transaction and other related costs 2,930 215 3,938 827 Net (gain) loss on asset disposals (1) 1,136 5,202 (7,697 ) 11,106 Insurance recoveries (2) — — — (1,557 ) Environmental related costs 1,174 39 2,501 526 Other, net 1,948 2,334 3,704 4,382 $ 15,795 $ 16,501 $ 28,353 $ 41,688 (1) During the nine months ended September 30, 2019 , the Company recognized a gain of $11,362 related to the sale of a product line. Refer to Note 6 of these condensed consolidated financial statements for additional details. (2) During the nine months ended September 30, 2018 , the Company recognized $2,500 of insurance recoveries in its condensed consolidated statements of income related to the Company’s claim for losses sustained during Hurricane Harvey in August 2017. For the nine months ended September 30, 2018 , $1,557 was recorded as a gain in other operating expense, net, as reimbursement of expenses, $207 was recorded as a gain in net loss on asset disposals within other operating expense, net, for the Company’s previously recognized property losses, and $736 represented recoveries in excess of the Company’s property losses which was recorded as a non-operating gain in other expense, net, in the Company’s condensed consolidated statements of income.

Inventories, Net

Inventories, Net	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Inventories, Net	9. Inventories, Net: Inventories, net, are classified and valued as follows: September 30, December 31, Finished products and work in process $ 206,419 $ 206,188 Raw materials 53,347 58,560 $ 259,766 $ 264,748 Valued at lower of cost or market: LIFO basis $ 155,089 $ 160,863 Valued at lower of cost and net realizable value: FIFO or average cost basis 104,677 103,885 $ 259,766 $ 264,748

Investments in Affiliated Compa

Investments in Affiliated Companies	9 Months Ended
	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investments in Affiliated Companies	10. 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, 2019 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% Asociacion para el Estudio de las Tecnologias de Equipamiento de Carreteras, S.A. (“Aetec”) Spain 20% Following is summarized information of the combined investments (1) : Three months ended Nine months ended 2019 2018 2019 2018 Sales $ 121,471 $ 74,088 $ 279,503 $ 271,562 Gross profit 48,416 24,495 102,966 100,686 Operating income 37,958 14,594 74,217 72,257 Net income 37,852 14,545 75,002 72,204 (1) Summarized information of the combined investments is presented at 100%; the Company’s share of the net assets and net income of affiliates is calculated based on the percent ownership specified in the table above. The Company’s investments in affiliated companies balance as of September 30, 2019 and December 31, 2018 includes net purchase accounting fair value adjustments of $252,190 and $258,066 , respectively, related to the series of transactions consummated on May 4, 2016 to reorganize and combine the businesses of PQ Holdings Inc. and Eco Services Operations LLC, 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 $1,658 and $5,875 of amortization expense related to purchase accounting fair value adjustments for the three and nine months ended September 30, 2019 , respectively. Consolidated equity in net income from affiliates is net of $1,658 and $4,975 of amortization expense related to purchase accounting fair value adjustments for the three and nine months ended September 30, 2018 , respectively.

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	11. Property, Plant and Equipment: A summary of property, plant and equipment, at cost, and related accumulated depreciation is as follows: September 30, December 31, Land $ 189,234 $ 190,772 Buildings 219,380 212,284 Machinery and equipment 1,162,273 1,125,117 Construction in progress 111,984 102,185 1,682,871 1,630,358 Less: accumulated depreciation (504,392 ) (421,379 ) $ 1,178,479 $ 1,208,979 Depreciation expense was $31,554 and $30,626 for the three months ended September 30, 2019 and 2018 , respectively. Depreciation expense was $97,088 and $99,491 for the nine months ended September 30, 2019 and 2018 , respectively.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases, Finance Leases	12. Leases: The Company has operating and finance lease agreements with remaining lease terms as of September 30, 2019 of up to 30 years, including leases of land, buildings, railcars, vehicles, manufacturing equipment and general office equipment. Some leases include options to terminate or extend for one or more years. These options are incorporated in the Company’s lease term when it is reasonably certain that the option will be exercised. Some leases include options to purchase, which the Company assesses under the guidance to determine if these leases should be classified as finance lease agreements. When the Company enters into an arrangement, at inception, the Company determines if the arrangement contains a lease and whether that lease meets the classification criteria of a finance or operating lease. Some of the Company’s lease arrangements contain lease components (e.g. minimum rent payments) and non-lease components (e.g. maintenance). The Company accounts for the lease and non-lease components based on the estimated standalone price of each component. Certain of the Company’s lease agreements include rental payments that are adjusted periodically for an index or rate and these are initially measured using the index or rate in effect at the commencement date. Variable lease expense is recognized in the period in which the obligation for those payments is incurred. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. The Company recognizes a right-of-use lease asset and lease liability at the lease commencement date based on the present value of the remaining lease payments over the lease term using the Company’s incremental borrowing rate. The Company is required to use the rate of interest that it would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. When the Company is unable to readily determine the discount rate implicit in the lease agreement, the Company utilizes its incremental borrowing rate over the relevant lease term. Short-term leases, which have an initial term of twelve months or less, are not recorded on the Company’s balance sheet. Lease expense for operating leases is recognized on a straight-line basis over the lease term. Operating lease costs of $4,858 and $14,217 are included in cost of goods sold and in selling, general and administrative expenses on the condensed consolidated statements of income for the three and nine months ended September 30, 2019 , respectively. Lease expense for financing leases is bifurcated into two components, with the amortization expense component of the right-of-use asset recognized on a straight-line basis and the interest expense component recognized using the effective interest method over the lease term. The amortization expense component of the right-of-use lease asset is included in cost of goods sold and in selling, general and administrative expenses and the interest expense component is included in interest expense, net on the condensed consolidated statements of income. Finance lease, short-term lease and variable lease costs for the three and nine months ended September 30, 2019 were not material. Lease income is not material to the results of operations for the three and nine months ended September 30, 2019 . The table below presents the operating and finance right-of-use lease assets and lease liabilities recognized on the condensed consolidated balance sheet as of September 30, 2019 : Classification September 30, Assets Operating lease assets Right-of-use lease assets $ 54,238 Finance lease assets Property, plant and equipment, net 1,582 Total leased assets $ 55,820 Liabilities Current: Operating lease liabilities Operating lease liabilities—current $ 14,095 Finance lease liabilities Accrued liabilities 176 Noncurrent: Operating lease liabilities Operating lease liabilities—noncurrent 38,473 Finance lease liabilities Other long-term liabilities 364 Total lease liabilities $ 53,108 The Company’s weighted average remaining lease term and weighted average discount rate for operating leases as of September 30, 2019 are as follows: September 30, Weighted average remaining lease term (in years): Operating leases 5.86 Finance leases 2.90 Weighted average discount rate: Operating leases 5.74 % Finance leases 4.67 % Maturities of lease liabilities as of September 30, 2019 are as follows: Operating Leases Finance Leases Remainder of 2019 $ 16,522 $ 47 2020 13,198 201 2021 9,816 201 2022 7,256 123 2023 4,767 3 Thereafter 11,395 — Total lease payments 62,954 575 Less: Interest (10,386 ) (35 ) Total lease liabilities (1) $ 52,568 $ 540 (1) Refer to the above table regarding the Company’s right-of-use lease assets and lease liabilities for the presentation of the lease liabilities in the Company’s condensed consolidated balance sheet at September 30, 2019 . At December 31, 2018 , future minimum payments under non-cancelable operating leases under previous lease guidance was as follows: Year Amount 2019 $ 18,457 2020 14,344 2021 11,432 2022 8,354 2023 6,198 Thereafter 17,477 $ 76,262 The following table presents other information related to our operating and finance leases and the impact on the Company’s condensed consolidated statement of cash flows: Nine months ended Cash paid for amounts included in the measurement of lease liabilities: Payments on operating leases included in operating cash flows $ 12,158 Interest payments under finance lease obligations included in operating cash flows 29 Principal payments under finance lease obligations included in financing cash flows 169 Right-of-use assets obtained in exchange for new lease liabilities (non-cash): Operating leases 5,148 Finance leases —
Leases, Operating Leases	12. Leases: The Company has operating and finance lease agreements with remaining lease terms as of September 30, 2019 of up to 30 years, including leases of land, buildings, railcars, vehicles, manufacturing equipment and general office equipment. Some leases include options to terminate or extend for one or more years. These options are incorporated in the Company’s lease term when it is reasonably certain that the option will be exercised. Some leases include options to purchase, which the Company assesses under the guidance to determine if these leases should be classified as finance lease agreements. When the Company enters into an arrangement, at inception, the Company determines if the arrangement contains a lease and whether that lease meets the classification criteria of a finance or operating lease. Some of the Company’s lease arrangements contain lease components (e.g. minimum rent payments) and non-lease components (e.g. maintenance). The Company accounts for the lease and non-lease components based on the estimated standalone price of each component. Certain of the Company’s lease agreements include rental payments that are adjusted periodically for an index or rate and these are initially measured using the index or rate in effect at the commencement date. Variable lease expense is recognized in the period in which the obligation for those payments is incurred. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. The Company recognizes a right-of-use lease asset and lease liability at the lease commencement date based on the present value of the remaining lease payments over the lease term using the Company’s incremental borrowing rate. The Company is required to use the rate of interest that it would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. When the Company is unable to readily determine the discount rate implicit in the lease agreement, the Company utilizes its incremental borrowing rate over the relevant lease term. Short-term leases, which have an initial term of twelve months or less, are not recorded on the Company’s balance sheet. Lease expense for operating leases is recognized on a straight-line basis over the lease term. Operating lease costs of $4,858 and $14,217 are included in cost of goods sold and in selling, general and administrative expenses on the condensed consolidated statements of income for the three and nine months ended September 30, 2019 , respectively. Lease expense for financing leases is bifurcated into two components, with the amortization expense component of the right-of-use asset recognized on a straight-line basis and the interest expense component recognized using the effective interest method over the lease term. The amortization expense component of the right-of-use lease asset is included in cost of goods sold and in selling, general and administrative expenses and the interest expense component is included in interest expense, net on the condensed consolidated statements of income. Finance lease, short-term lease and variable lease costs for the three and nine months ended September 30, 2019 were not material. Lease income is not material to the results of operations for the three and nine months ended September 30, 2019 . The table below presents the operating and finance right-of-use lease assets and lease liabilities recognized on the condensed consolidated balance sheet as of September 30, 2019 : Classification September 30, Assets Operating lease assets Right-of-use lease assets $ 54,238 Finance lease assets Property, plant and equipment, net 1,582 Total leased assets $ 55,820 Liabilities Current: Operating lease liabilities Operating lease liabilities—current $ 14,095 Finance lease liabilities Accrued liabilities 176 Noncurrent: Operating lease liabilities Operating lease liabilities—noncurrent 38,473 Finance lease liabilities Other long-term liabilities 364 Total lease liabilities $ 53,108 The Company’s weighted average remaining lease term and weighted average discount rate for operating leases as of September 30, 2019 are as follows: September 30, Weighted average remaining lease term (in years): Operating leases 5.86 Finance leases 2.90 Weighted average discount rate: Operating leases 5.74 % Finance leases 4.67 % Maturities of lease liabilities as of September 30, 2019 are as follows: Operating Leases Finance Leases Remainder of 2019 $ 16,522 $ 47 2020 13,198 201 2021 9,816 201 2022 7,256 123 2023 4,767 3 Thereafter 11,395 — Total lease payments 62,954 575 Less: Interest (10,386 ) (35 ) Total lease liabilities (1) $ 52,568 $ 540 (1) Refer to the above table regarding the Company’s right-of-use lease assets and lease liabilities for the presentation of the lease liabilities in the Company’s condensed consolidated balance sheet at September 30, 2019 . At December 31, 2018 , future minimum payments under non-cancelable operating leases under previous lease guidance was as follows: Year Amount 2019 $ 18,457 2020 14,344 2021 11,432 2022 8,354 2023 6,198 Thereafter 17,477 $ 76,262 The following table presents other information related to our operating and finance leases and the impact on the Company’s condensed consolidated statement of cash flows: Nine months ended Cash paid for amounts included in the measurement of lease liabilities: Payments on operating leases included in operating cash flows $ 12,158 Interest payments under finance lease obligations included in operating cash flows 29 Principal payments under finance lease obligations included in financing cash flows 169 Right-of-use assets obtained in exchange for new lease liabilities (non-cash): Operating leases 5,148 Finance leases —

Long-term Debt

Long-term Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Long-term Debt	13. Long-term Debt: The summary of long-term debt is as follows: September 30, December 31, 2018 Term Loan Facility $ 1,057,497 $ 1,157,498 6.75% Senior Secured Notes due 2022 625,000 625,000 5.75% Senior Unsecured Notes due 2025 295,000 300,000 ABL Facility — — Other 65,778 65,925 Total debt 2,043,275 2,148,423 Original issue discount (15,331 ) (18,584 ) Deferred financing costs (13,017 ) (15,882 ) Total debt, net of original issue discount and deferred financing costs 2,014,927 2,113,957 Less: current portion (8,210 ) (7,237 ) Total long-term debt, excluding current portion $ 2,006,717 $ 2,106,720 The fair value of a financial instrument is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. As of September 30, 2019 and December 31, 2018 , the fair value of the term loan facility and senior secured and unsecured notes was $2,009,555 and $2,010,023 , respectively. The fair value is classified as Level 2 based upon the fair value hierarchy (see Note 4 to these condensed consolidated financial statements for further information on fair value measurements). Term Loan Facility During the quarter ended September 30, 2019 , the Company prepaid $100,000 of outstanding principal balance on the Term Loan Facility. The Company wrote off $502 of previously unamortized deferred financing costs and original issue discount of $1,181 as debt extinguishment costs related to the Term Loan Facility for the three months ended September 30, 2019 .

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	14. Financial Instruments: The Company uses (1) interest rate related derivative instruments to manage its exposure to changes in interest rates on its variable-rate debt instruments, (2) commodity derivatives to manage its exposure to commodity price fluctuations, and (3) foreign currency related derivative instruments to manage its foreign currency exposure to its net investments in certain foreign operations. The Company does not speculate using derivative instruments. By using derivative financial instruments to hedge exposures to changes in interest rates, commodity prices and foreign currency, 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 the Company’s derivative instruments 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, in the Company’s consolidated balance sheet. As the derivatives are designated and qualify as cash flow hedges, the gains or losses on the natural gas swaps are recorded in stockholders’ equity as a component of other comprehensive income (loss) (“OCI”), net of tax. Reclassifications of the gains and losses on natural gas hedges into earnings are recorded in production costs and subsequently charged to cost of goods sold in the condensed consolidated statements of income in the period in which the associated inventory is sold. As of September 30, 2019 , the Company’s natural gas swaps had a remaining notional quantity of 3.3 million MMBTU to mitigate commodity price volatility through December 2021. 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. Changes in interest rates will not affect the market value of such debt but will affect the Company’s 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 in its consolidated balance sheet. As the derivatives are designated and qualify as cash flow hedges, the gains or losses on the interest rate cap agreements are recorded in stockholders’ equity as a component of OCI, net of tax. Reclassifications of the gains and losses on the interest rate cap agreements into earnings are recorded as part of interest expense in the condensed consolidated statements of income as the Company makes its interest payments on the hedged portion of its senior secured credit facilities. 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 cap rate currently in effect at September 30, 2019 is 3.00% . In November 2018, the Company entered into additional interest rate cap agreements to mitigate interest rate volatility from July 2020 through July 2022, with a cap rate of 3.50% on $500,000 of notional variable-rate debt. Use of Derivative Financial Instruments to Manage Foreign Currency Risk. The Company is exposed to risks related to its net investments in foreign operations due to fluctuations in foreign currency exchange rates, particularly between the United States dollar and the Euro. In February 2018, the Company entered into multiple cross-currency interest rate swap arrangements with an aggregate notional amount of €280,000 ( $306,345 as of September 30, 2019 ) to hedge this exposure on the net investments of certain of its Euro-denominated subsidiaries. The Company records these swap agreements at fair value as assets or liabilities in its consolidated balance sheet. As the derivatives are designated and qualify as net investment hedges, changes in the fair value of the swaps attributable to changes in the spot exchange rates are recognized in cumulative translation adjustment (“CTA”) within OCI and are held there until the hedged net investments are sold or substantially liquidated. Upon such sale or liquidation, the amount recognized in CTA is reclassified to earnings and reported in the same line item as the gain or loss on the liquidation of the net investments. Changes in the fair value of the swaps attributable to the cross-currency basis spread are excluded from the assessment of hedge effectiveness and are recorded in current period earnings. The fair values of derivative instruments held as of September 30, 2019 and December 31, 2018 are shown below: Balance sheet location September 30, 2019 December 31, 2018 Derivative assets: Derivatives designated as cash flow hedges: Natural gas swaps Prepaid and other current assets $ — $ 21 Interest rate caps Prepaid and other current assets — 1,358 Interest rate caps Other long-term assets — 546 — 1,925 Derivatives designed as net investment hedges: Cross-currency interest rate swaps Prepaid and other current assets 7,517 5,499 Cross-currency interest rate swaps Other long-term assets 32,608 13,344 40,125 18,843 Total derivative assets $ 40,125 $ 20,768 Derivative liabilities: Derivatives designated as cash flow hedges: Natural gas swaps Accrued liabilities $ 626 $ 36 Natural gas swaps Other long-term liabilities 302 148 Interest rate caps Other long-term liabilities 3,202 1,842 Total derivative liabilities $ 4,130 $ 2,026 The following tables show the effect of the Company’s derivative instruments designated as cash flow hedges on AOCI for the three and nine months ended September 30, 2019 and 2018 : Three months ended September 30, 2019 2018 Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Interest rate caps Interest (expense) income $ (216 ) $ (157 ) $ (93 ) $ (71 ) Natural gas swaps Cost of goods sold (185 ) (291 ) (300 ) (30 ) $ (401 ) $ (448 ) $ (393 ) $ (101 ) Nine months ended September 30, 2019 2018 Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Interest rate caps Interest (expense) income $ (3,264 ) $ (449 ) $ (3,396 ) $ (164 ) Natural gas swaps Cost of goods sold (951 ) (187 ) (482 ) (101 ) $ (4,215 ) $ (636 ) $ (3,878 ) $ (265 ) The following tables show the effect of the Company’s cash flow hedge accounting on the condensed consolidated statements of income for the three and nine months ended September 30, 2019 and 2018 : Location and amount of gain (loss) recognized in income on cash flow hedging relationships Three months ended September 30, 2019 2018 Cost of goods sold Interest (expense) income Cost of goods sold Interest (expense) income Total amounts of income and expense line items presented in the statement of income in which the effects of cash flow hedges are recorded $ (310,904 ) $ (27,697 ) $ (319,703 ) $ (28,238 ) The effects of cash flow hedging: Gain (loss) on cash flow hedging relationships: Interest contracts: Amount of gain (loss) reclassified from AOCI into income — (157 ) — (71 ) Commodity contracts: Amount of gain (loss) reclassified from AOCI into income (291 ) — (30 ) — Location and amount of gain (loss) recognized in income on cash flow hedging relationships Nine months ended September 30, 2019 2018 Cost of goods sold Interest (expense) income Cost of goods sold Interest (expense) income Total amounts of income and expense line items presented in the statement of income in which the effects of cash flow hedges are recorded (905,395 ) (84,855 ) (934,088 ) (84,622 ) The effects of cash flow hedging: Gain (loss) on cash flow hedging relationships: Interest contracts: Amount of gain (loss) reclassified from AOCI into income — (449 ) — (164 ) Commodity contracts: Amount of gain (loss) reclassified from AOCI into income (187 ) — (101 ) — The amount of unrealized losses in AOCI related to the Company’s cash flow hedges that is expected to be reclassified to the condensed consolidated statement of income over the next twelve months is $1,431 as of September 30, 2019 . The following tables show the effect of the Company’s net investment hedges on AOCI and the condensed consolidated statements of income for the three and nine months ended September 30, 2019 and 2018 : Amount of gain (loss) recognized in OCI on derivative Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) reclassified from AOCI into income Location of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Three months ended September 30, Three months ended September 30, Three months ended September 30, 2019 2018 2019 2018 2019 2018 Cross-currency interest rate swaps $ 15,342 $ 1,138 Gain (loss) on sale of subsidiary $ — $ — Interest (expense) income $ 2,395 $ 2,271 Amount of gain (loss) recognized in OCI on derivative Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) reclassified from AOCI into income Location of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Nine months ended Nine months ended Nine months ended 2019 2018 2019 2018 2019 2018 Cross-currency interest rate swaps $ 21,282 $ 8,799 Gain (loss) on sale of subsidiary $ — $ — Interest (expense) income $ 6,888 $ 5,662

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	15. Income Taxes: The effective income tax rate for the three months ended September 30, 2019 was 38.4% compared to 37.0% for the three months ended September 30, 2018 . The effective income tax rate for the nine months ended September 30, 2019 was 39.3% compared to 40.9% for the nine months ended September 30, 2018 . The Company’s effective income tax rate has fluctuated primarily because of changes in income mix (including the effect of loss companies), the impact of including foreign earnings in U.S. taxable income and changes in foreign exchange gains and losses, which create permanent differences in certain jurisdictions. The difference between the U.S. federal statutory income tax rate and the Company’s effective income tax rate for the nine months ended September 30, 2019 was mainly due to the tax effect of permanent differences related to foreign currency exchange gain or loss, inclusion of foreign earnings in U.S. taxable income, pre-tax losses with no associated tax benefit, the discrete tax effects of the Company’s sale of a non-core product line and state taxes. The difference between the U.S. federal statutory income tax rate and the Company’s effective income tax rate for the nine months ended September 30, 2018 was mainly due to the tax effect of permanent differences related to foreign currency exchange gain or loss, inclusion of foreign earnings in the U.S. as a result of recently enacted tax law, pre-tax losses with no associated tax benefit, discrete impacts of opening balance sheet adjustments related to the Sovitec acquisition and state taxes. The TCJA enacted certain provisions that became effective on January 1, 2018. These provisions include, but are not limited to, the new Global Intangible Low-Taxed Income (“GILTI”) tax rules. Due to the complexity of the new GILTI tax, the Company is continuing to evaluate the GILTI provision of the TCJA and its impact on the financial statements, which remains uncertain. Per guidance issued by the FASB, the Company is permitted to make an accounting policy election to either (1) treat the taxes incurred as a result of the GILTI provision as a current-period expense when incurred or (2) factor such amounts into its measurement of deferred taxes. The Company has elected to treat any tax expense incurred as a result of GILTI as a current-period expense. Additionally, in regards to GILTI’s impact in assessing the ability to realize deferred tax assets, the Company has made a policy election to use the tax law ordering approach. With respect to operating results for the three and nine months ended September 30, 2019 , the Company has continued to incorporate an estimate of the GILTI income inclusion when estimating annual effective tax rate used for GAAP purposes. The Company expects this amount to be included in its 2019 U.S. taxable income. However, the estimated 2019 GILTI income inclusion may change materially as the Company continues to evaluate future legislative or administrative guidance that is put forth, any updates to assumptions and figures used for the current estimate, or as a result of future changes to the Company’s current structure and business.

Benefit Plans

Benefit Plans	9 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Benefit Plans	16. 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 (benefit) are as follows: Defined Benefit Pension Plans U.S. Foreign Three months ended Three months ended 2019 2018 2019 2018 Service cost $ 251 $ 243 $ 780 $ 933 Interest cost 2,653 2,395 801 (601 ) Expected return on plan assets (2,912 ) (3,165 ) (782 ) 453 Amortization of net loss — — 1 13 Amortization of prior service cost — — 6 — Net periodic expense (benefit) $ (8 ) $ (527 ) $ 806 $ 798 U.S. Foreign Nine months ended Nine months ended 2019 2018 2019 2018 Service cost $ 751 $ 776 $ 2,464 $ 2,665 Interest cost 7,958 7,137 2,458 2,512 Expected return on plan assets (8,733 ) (9,515 ) (2,375 ) (2,494 ) Amortization of net loss — — 1 38 Amortization of prior service cost — — 18 — Curtailment gain recognized — (576 ) — — Net periodic expense (benefit) $ (24 ) $ (2,178 ) $ 2,566 $ 2,721 Supplemental Retirement Plans Three months ended Nine months ended 2019 2018 2019 2018 Interest cost $ 121 $ 110 $ 364 $ 330 Net periodic expense $ 121 $ 110 $ 364 $ 330 Other Postretirement Benefit Plans Three months ended Nine months ended 2019 2018 2019 2018 Service cost $ 3 $ 3 $ 10 $ 12 Interest cost 38 43 114 108 Amortization of prior service credit (32 ) (40 ) (97 ) (79 ) Amortization of net gain (9 ) (11 ) (27 ) (33 ) Net periodic expense (benefit) $ — $ (5 ) $ — $ 8

Commitments and Contingent Liab

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	17. 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 comply 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. While management believes that the liabilities resulting from such lawsuits and claims are not probable or reasonably estimable, certain accruals have been reflected in the Company’s condensed consolidated financial statements. When these matters are ultimately concluded and determined, the Company believes that there will be no material adverse effect on its consolidated financial position, results of operations or liquidity.

Reportable Segments

Reportable Segments	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Reportable Segments	18. Reportable Segments: Summarized financial information for the Company’s reportable segments is shown in the following table: Three months ended Nine months ended 2019 2018 2019 2018 Sales: Refining Services $ 118,335 $ 123,369 $ 341,469 $ 336,154 Catalysts (1) 25,612 16,347 62,335 50,167 Performance Materials 115,134 115,380 295,095 304,660 Performance Chemicals 167,949 174,722 526,239 548,446 Eliminations (2) (3,229 ) (2,615 ) (10,441 ) (11,314 ) Total $ 423,801 $ 427,203 $ 1,214,697 $ 1,228,113 Segment Adjusted EBITDA: (3) Refining Services $ 51,166 $ 49,559 $ 133,721 $ 126,368 Catalysts (4) 31,638 15,751 79,372 62,227 Performance Materials 25,769 21,255 65,505 61,880 Performance Chemicals 36,804 41,832 120,642 131,748 Total Segment Adjusted EBITDA (5) $ 145,377 $ 128,397 $ 399,240 $ 382,223 (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 $54,414 and $32,297 for the three months ended September 30, 2019 and 2018 , respectively. The proportionate share of sales is $123,016 and $120,159 for the nine months ended September 30, 2019 and 2018 , respectively. (2) The Company eliminates intersegment sales when reconciling to the Company’s condensed consolidated statements of income. (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 Catalysts segment is $22,628 for the three months ended September 30, 2019 , which includes $17,248 of equity in net income plus $1,658 of amortization of investment in affiliate step-up and $3,722 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Catalysts segment is $10,513 for the three months ended September 30, 2018 , which includes $5,563 of equity in net income plus $1,658 of amortization of investment in affiliate step-up and $3,292 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Catalysts segment is $48,621 for the nine months ended September 30, 2019 , which includes $31,548 of equity in net income plus $5,875 of amortization of investment in affiliate step-up and $11,198 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Catalysts segment is $45,194 for the nine months ended September 30, 2018 , which includes $31,005 of equity in net income plus $4,975 of amortization of investment in affiliate step-up and $9,214 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 of net income attributable to PQ Group Holdings to Segment Adjusted EBITDA is as follows: Three months ended Nine months ended 2019 2018 2019 2018 Reconciliation of net income attributable to PQ Group Holdings Inc. to Segment Adjusted EBITDA Net income attributable to PQ Group Holdings Inc. $ 26,713 $ 14,185 $ 60,438 $ 30,181 Provision for income taxes 16,718 8,470 39,472 21,590 Interest expense, net 27,697 28,238 84,855 84,622 Depreciation and amortization 44,246 43,827 135,230 139,298 Segment EBITDA 115,374 94,720 319,995 275,691 Unallocated corporate expenses 7,693 10,276 28,062 27,322 Joint venture depreciation, amortization and interest 3,722 3,292 11,198 9,214 Amortization of investment in affiliate step-up 1,658 1,658 5,875 4,975 Amortization of inventory step-up — — — 1,603 Debt extinguishment costs 1,767 864 1,767 6,743 Net (gain) loss on asset disposals 1,136 5,202 (7,697 ) 11,106 Foreign currency exchange loss 4,457 3,527 5,380 15,347 LIFO expense 534 856 10,814 5,903 Transaction and other related costs 670 210 1,725 895 Equity-based compensation 4,806 4,252 13,576 11,879 Restructuring, integration and business optimization expenses 717 2,178 1,436 5,662 Defined benefit pension plan cost 834 112 2,379 260 Other 2,009 1,250 4,730 5,623 Segment Adjusted EBITDA $ 145,377 $ 128,397 $ 399,240 $ 382,223

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2019
Stock-Based Compensation [Abstract]
Stock-Based Compensation	19. Stock-Based Compensation: The Company is authorized to issue shares for common stock awards to employees, directors and affiliates of the Company in connection with the PQ Group Holdings Inc. 2017 Omnibus Incentive Plan (the “2017 Plan”). During the nine months ended September 30, 2019 , the Company granted 1,245,628 restricted stock units and 550,676 performance stock units at target under the 2017 Plan as part of its equity incentive compensation program. Each restricted stock unit provides the recipient with the right to receive a share of common stock subject to graded vesting terms based on service, which for the awards granted during the nine months ended September 30, 2019 , requires approximately one year of service for members of the Company’s board of directors and approximately three years of service for employees. The performance stock units granted during the nine months ended September 30, 2019 provide the recipients with the right to receive shares of common stock dependent on the achievement of two Company-specific financial performance targets and the provision of service through the vesting date. Achievement of the metrics is measured based on the average levels of achievement across the three-year period from January 1, 2019 through December 31, 2021. Depending on the Company’s performance against the pre-determined thresholds for achievement, each performance stock unit award holder is eligible to earn a percentage of the target number of shares granted to the holder, ranging from zero to 200% . The performance stock units, to the extent earned, will vest on the date the Company’s compensation and governance committee certifies the achievement of the performance metrics for the three -year period ending December 31, 2021, which will occur no later than March 1, 2022. The value of the restricted stock units granted during the nine months ended September 30, 2019 was based on the average of the high and low trading prices of the Company’s common stock on the NYSE on the preceding trading day, in accordance with the Company’s policy for valuing such awards. Compensation expense related to the restricted stock units is recognized on a straight-line basis over the respective vesting period. The value of the performance stock units granted during the nine months ended September 30, 2019 was measured on the same basis as that of the restricted stock units, and based on the target number of shares granted; because the performance vesting conditions affect the ability of the recipients to vest in the awards, they are not factored into the fair value measure of the award. Compensation expense related to the performance stock units is recognized ratably over the requisite service period, and the Company must assess the probability that the performance conditions will be met each reporting period, and the level at which they are estimated to be attained. Should the probability assessment change during a given reporting period, the total compensation cost (both recognized and unrecognized) will be adjusted to reflect the revised assessment. The following table summarizes the activity for the Company’s restricted stock units and performance stock units for the nine months ended September 30, 2019 : Restricted Stock Units Performance Stock Units Number of Weighted Average Grant Date Fair Value (per share) Number of Weighted Average Grant Date Fair Value (per share) Nonvested as of December 31, 2018 998,786 $ 16.83 — $ — Granted 1,245,628 $ 15.42 550,676 $ 15.41 Vested (148,551 ) $ 15.90 — $ — Forfeited (20,837 ) $ 16.00 — $ — Nonvested as of September 30, 2019 2,075,026 $ 16.06 550,676 $ 15.41 Total stock-based compensation expense for all of the Company’s equity incentive awards was $4,806 and $4,252 for the three months ended September 30, 2019 and 2018 , respectively, and $13,576 and $11,879 for the nine months ended September 30, 2019 and 2018 , respectively. The income tax benefit recognized in the condensed consolidated statements of income was $1,187 and $1,051 for the three months ended September 30, 2019 and 2018 , respectively, and $3,353 and $2,935 for the nine months ended September 30, 2019 and 2018 , respectively. With the new grants of restricted stock units and performance stock units during the nine months ended September 30, 2019 , unrecognized compensation cost at September 30, 2019 related to nonvested awards was $ 22,434 and $ 6,906 for restricted stock units and performance stock units, respectively. The weighted-average period over which these costs are expected to be recognized at September 30, 2019 is 1.72 years for the restricted stock units and 2.41 years for the performance stock units. At September 30, 2019 , 3,841,617 shares of common stock were available for issuance under the 2017 Plan, after giving effect to the new grants as well as other minor activity during the nine months ended September 30, 2019 . Activity related to the Company’s stock options and restricted stock awards was not material for the nine months ended September 30, 2019 .

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings per Share	20. 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. The weighted average number of common shares outstanding during the period for the computation of basic earnings per share excludes restricted stock awards that have legally been issued but are nonvested during the period, as the sale of these shares is prohibited pending satisfaction of certain vesting conditions by the award recipients in order to earn the rights to the shares. 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, if dilutive. Potential common shares reflect (1) unvested restricted stock awards and restricted stock units with service vesting conditions, (2) performance stock units with vesting conditions considered probable of achievement and (3) options to purchase common stock, all of which have been included in the diluted earnings per share calculation using the treasury stock method. The reconciliation from basic to diluted weighted average shares outstanding is as follows: Three months ended Nine months ended 2019 2018 2019 2018 Weighted average shares outstanding – Basic 134,511,819 133,336,352 134,213,571 133,237,653 Dilutive effect of unvested common shares and restricted stock units with service conditions, performance stock units considered probable of vesting and assumed stock option exercises and conversions 1,137,891 1,239,810 1,091,799 985,975 Weighted average shares outstanding – Diluted 135,649,710 134,576,162 135,305,370 134,223,628 Basic and diluted earnings per share are calculated as follows: Three months ended Nine months ended 2019 2018 2019 2018 Numerator: Net income attributable to PQ Group Holdings Inc. $ 26,713 $ 14,185 $ 60,438 $ 30,181 Denominator: Weighted average shares outstanding – Basic 134,511,819 133,336,352 134,213,571 133,237,653 Weighted average shares outstanding – Diluted 135,649,710 134,576,162 135,305,370 134,223,628 Net income per share: Basic income per share $ 0.20 $ 0.11 $ 0.45 $ 0.23 Diluted income per share $ 0.20 $ 0.11 $ 0.45 $ 0.22 The table below presents the details of the Company’s weighted average equity-based awards outstanding during each respective period that were excluded from the calculation of diluted earnings per share: Three months ended Nine months ended 2019 2018 2019 2018 Restricted stock awards with performance only targets not yet achieved 1,537,572 1,709,463 1,601,474 1,719,775 Stock options with performance only targets not yet achieved 578,564 586,253 583,204 586,253 Anti-dilutive restricted stock awards, restricted stock units and performance stock units — — — 18,076 Anti-dilutive stock options 863,063 760,766 863,063 668,596 Restricted stock awards and stock options with performance only vesting conditions were not included in the dilution calculation, as the performance targets have not been achieved nor were probable of achievement as of the end of the respective periods. On a weighted average basis, options to purchase 621,747 shares of common stock at $16.97 per share for the three and nine months ended September 30, 2019 and 2018 , 241,316 shares of common stock at $17.50 per share for the three and nine months ended September 30, 2019 and 139,019 and 46,849 shares of common stock at $17.50 per share for the three and nine months ended September 30, 2018 , respectively, were excluded from the computation of diluted earnings per share for the respective periods, because the combination of the options’ exercise price and remaining unamortized stock-based compensation expense was greater than the average market price of the common shares. The 621,747 stock options expire on October 2, 2027, while the 241,316 stock options expire on August 9, 2028. All of the options were outstanding as of September 30, 2019 . Anti-dilutive awards are not included in the dilution calculation, as their inclusion would have the effect of increasing diluted income per share.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	21. Supplemental Cash Flow Information: The following table presents supplemental cash flow information for the Company: Nine months ended 2019 2018 Cash paid during the period for: Income taxes, net of refunds $ 13,261 $ 16,121 Interest (1) 82,349 83,612 Non-cash investing activity (2) : Capital expenditures acquired on account but unpaid as of the period end 13,265 10,624 (1) Excludes capitalized interest for the periods presented, as well as $8,435 and $4,279 of net interest proceeds on swaps designated as net investment hedges for the nine months ended September 30, 2019 and 2018 , respectively, all of which is included within cash flows from investing activities in the Company’s condensed consolidated statements of cash flows. (2) For the supplemental non-cash information on lease liabilities arising from obtaining right-of-use lease assets, see Note 12 to these condensed consolidated financial statements for additional details. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets as of September 30, 2019 and 2018 to the total of the same amounts shown in the condensed consolidated statements of cash flows for the nine months then ended: September 30, 2019 2018 Cash and cash equivalents $ 78,510 $ 56,684 Restricted cash included in prepaid and other current assets 1,745 1,333 Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows $ 80,255 $ 58,017

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	22. Subsequent Events: In October 2019, the Company settled all of its cross-currency interest rate swap arrangements (the “February 2018 swaps”) and concurrently entered into new cross-currency interest rate swap arrangements (the “October 2019 swaps”) with the same notional amount of €280,000 ( $311,379 ) and same maturity of February 2023. Consistent with the February 2018 swaps, the October 2019 swaps are designed to enable the Company to effectively convert a portion of its fixed-rate U.S. dollar-denominated debt obligations under the Term Loan Facility into a Euro-denominated equivalent. The October 2019 swaps have been designated and qualify as net investment hedges of the Company’s foreign currency exchange rate exposure on the net investments of certain of its Euro-denominated subsidiaries. The settlement of the February 2018 swaps resulted in cash proceeds to the Company of $38,070 , which the Company plans to use for additional debt repayment on the Company’s Term Loan Facility. Other than the settlement of the February 2018 swaps and concurrent execution of the October 2019 swaps, the Company has evaluated subsequent events since the balance sheet date and determined that there are no additional items to disclose.

Background and Basis of Prese_2

Background and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements included herein are unaudited. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (“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 Annual Report on Form 10-K for the year ended December 31, 2018 . Other than the update to our lease accounting policies described in Note 12 , the Company has continued to follow the accounting policies set forth in those consolidated financial statements.
Recently Issued Accounting Standards	Recently Adopted Accounting Standards In February 2016, the Financial Accounting Standards Board (“FASB”) issued guidance (with subsequent targeted amendments) that modifies the accounting for leases. Under the new guidance, a lessee recognizes right-of-use lease assets and lease liabilities for most leases (including those classified under existing GAAP as operating leases, which based on previous standards are not reflected on the balance sheet), but recognizes expenses in a manner that is generally consistent with existing practices. The new guidance also requires companies to provide expanded disclosures regarding leasing arrangements. For public companies, the new guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. The new guidance must be adopted using a modified retrospective transition method. The Company adopted the new lease guidance effective January 1, 2019 as required using the modified retrospective transition method and applied the provisions of the guidance at the effective date with a cumulative-effect adjustment to the opening balance of retained earnings without adjusting the comparative periods presented. The new guidance provides practical expedients and allows for certain policy elections with regard to the Company’s lease population. The Company has elected the short term lease accounting policy and will not record right-of-use lease assets or lease liabilities for leases with an initial term of twelve months or less. Additionally, the Company has elected to utilize the portfolio approach to apply incremental borrowing rates to its leases. The Company has elected the package of practical expedients which provides the Company with the ability to bypass reassessment of the following for leases existing at the date of adoption: (1) whether any existing contracts are, or contain, leases; (2) the lease classification for any existing leases; and (3) initial direct costs for any existing leases. The Company also elected the land easement practical expedient to carry forward existing accounting treatment on existing land easements. Adoption of the new lease guidance resulted in the recognition of right-of-use lease assets of $60,726 , which included $57,832 of right-of-use lease assets related to lease commitments and $2,895 related to the reclassification of favorable lease contracts, and lease liabilities of $58,929 . The new guidance had no impact on the Company’s operating results or liquidity upon adoption. Disclosures related to the Company’s leases are included in Note 12 to these condensed consolidated financial statements. In February 2018, the FASB issued guidance which permits entities to make a one-time election to reclassify the residual (“stranded”) income tax effects included in accumulated other comprehensive income (“AOCI”) to beginning retained earnings as a result of tax reform legislation enacted by the U.S. government on December 22, 2017, namely the Tax Cuts and Jobs Act of 2017 (“TCJA”). The standard is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. Prior to the enactment of the tax reform legislation on December 22, 2017, the Company had amounts recorded in AOCI related to its domestic pension, postretirement and supplementary benefit plans and cash flow hedging relationships that were based on pre-enactment tax rates, which were included in AOCI at the adoption date of the new guidance. The Company adopted the new guidance effective January 1, 2019 as required, and elected to reclassify the income tax effects stranded in AOCI related to the change in the U.S. federal corporate income tax rate from the TCJA of $1,874 from AOCI to beginning retained earnings. There were no other income tax effects related to the application of the TCJA that were included in this reclassification. The Company’s accounting policy for releasing income tax effects from AOCI is based on individual units of account. In June 2018, the FASB issued guidance which conforms the accounting for the issuance of all share-based payments using the same accounting model. Previously, the accounting for share-based payments to non-employees was covered under a different framework than those made to employees. Under the new guidance, awards to both employees and non-employees essentially follow the same model, with small variations related to determining the term assumption when valuing a non-employee award as well as a different expense attribution model for non-employee awards. The new guidance is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The Company adopted the new guidance on January 1, 2019 as required, with no material impact on its consolidated financial statements upon adoption. Accounting Standards Not Yet Adopted In August 2018, the FASB issued guidance which modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The guidance eliminates certain disclosure requirements, including the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next fiscal year and the effects of a one-percentage point change in assumed health care cost trend rates. The guidance also requires additional disclosure of the reasons for significant gains and losses related to changes in the benefit obligation for the period. The guidance is effective for fiscal years ending after December 15, 2020 with early adoption permitted, and is required to be applied on a retrospective basis to all periods presented. The Company will modify its benefit plan disclosures in accordance with the new guidance upon adoption, and the Company believes that the new guidance will not have a material impact on its consolidated financial statements. In August 2018, the FASB issued guidance which modifies certain disclosure requirements over fair value measurements. The guidance is effective for fiscal years beginning after December 15, 2019, including all interim periods within that fiscal year. The Company believes that the new guidance will not have a material impact 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 Securities and Exchange Commission (“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. The Company will apply the guidance to its goodwill impairment tests upon the required adoption date or earlier as permitted. In June 2016, the FASB issued guidance (with subsequent targeted amendments) that affects loans, trade receivables and any other financial assets that have the contractual right to receive cash. Under the new guidance, an entity is required to recognize expected credit losses rather than incurred losses for financial assets. The new guidance is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. The Company believes that the new guidance will not have a material impact on its consolidated financial statements.
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 16 to these condensed consolidated financial statements regarding defined supplementary retirement plans. The Company’s restoration plan assets are included in other long-term assets on its condensed consolidated balance sheets. Gains and losses related to these investments are included in other expense, net in the Company’s condensed consolidated statements of income. Unrealized gains and losses associated with the underlying stock and fixed income mutual funds were immaterial as of September 30, 2019 and December 31, 2018 , respectively. 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.
Leases	The Company has operating and finance lease agreements with remaining lease terms as of September 30, 2019 of up to 30 years, including leases of land, buildings, railcars, vehicles, manufacturing equipment and general office equipment. Some leases include options to terminate or extend for one or more years. These options are incorporated in the Company’s lease term when it is reasonably certain that the option will be exercised. Some leases include options to purchase, which the Company assesses under the guidance to determine if these leases should be classified as finance lease agreements. When the Company enters into an arrangement, at inception, the Company determines if the arrangement contains a lease and whether that lease meets the classification criteria of a finance or operating lease. Some of the Company’s lease arrangements contain lease components (e.g. minimum rent payments) and non-lease components (e.g. maintenance). The Company accounts for the lease and non-lease components based on the estimated standalone price of each component. Certain of the Company’s lease agreements include rental payments that are adjusted periodically for an index or rate and these are initially measured using the index or rate in effect at the commencement date. Variable lease expense is recognized in the period in which the obligation for those payments is incurred. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. The Company recognizes a right-of-use lease asset and lease liability at the lease commencement date based on the present value of the remaining lease payments over the lease term using the Company’s incremental borrowing rate. The Company is required to use the rate of interest that it would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. When the Company is unable to readily determine the discount rate implicit in the lease agreement, the Company utilizes its incremental borrowing rate over the relevant lease term. Short-term leases, which have an initial term of twelve months or less, are not recorded on the Company’s balance sheet. Lease expense for operating leases is recognized on a straight-line basis over the lease term. Operating lease costs of $4,858 and $14,217 are included in cost of goods sold and in selling, general and administrative expenses on the condensed consolidated statements of income for the three and nine months ended September 30, 2019 , respectively.

Revenue from Contracts with C_2

Revenue from Contracts with Customers Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The Company’s portfolio of products are integrated into a variety of end uses, which are described in the table below. Key End Uses Key Products Industrial & process chemicals • Silicate precursors for the tire industry • Glass beads, or microspheres, for metal finishing end uses Fuels & emission control • Refinery catalysts • Emission control catalysts • Catalyst recycling services • Silicate for catalyst manufacturing Packaging & engineered plastics • Catalysts for high-density polyethlene and chemicals syntheses • Antiblocks for film packaging • Solid and hollow microspheres for composite plastics • Sulfur derivatives for nylon production Highway safety & construction • Reflective markings for roadways and airports • Silica gels for surface coatings Consumer products • Silica gels for edible oil and beer clarification • Precipitated silicas, silicates and zeolites for the dentifrice and dishwasher and laundry detergent applications Natural resources • Silicates for drilling muds • Hollow glass beads, or microspheres, for oil well cements • Silicates and alum for water treatment mining • Bleaching aids for paper The following tables disaggregate the Company’s sales, by segment and end use, for the three and nine months ended September 30, 2019 and 2018 : Three months ended September 30, 2019 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 20,180 $ 47 $ 12,225 $ 54,696 $ 87,148 Fuels & emission control (1) 70,048 — — — 70,048 Packaging & engineered plastics 12,197 25,565 16,886 12,048 66,696 Highway safety & construction (1) — — 82,502 20,800 103,302 Consumer products — — — 64,849 64,849 Natural resources 15,910 — 3,521 15,556 34,987 Total segment sales 118,335 25,612 115,134 167,949 427,030 Eliminations (813 ) (47 ) (18 ) (2,351 ) (3,229 ) Total $ 117,522 $ 25,565 $ 115,116 $ 165,598 $ 423,801 Nine months ended September 30, 2019 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 60,485 $ 109 $ 38,037 $ 175,009 $ 273,640 Fuels & emission control (1) 191,243 — — — 191,243 Packaging & engineered plastics 38,953 62,226 51,863 41,121 194,163 Highway safety & construction (1) — — 195,119 65,036 260,155 Consumer products — — — 198,798 198,798 Natural resources 50,788 — 10,076 46,275 107,139 Total segment sales 341,469 62,335 295,095 526,239 1,225,138 Eliminations (2,595 ) (109 ) (170 ) (7,567 ) (10,441 ) Total $ 338,874 $ 62,226 $ 294,925 $ 518,672 $ 1,214,697 Three months ended September 30, 2018 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 21,027 $ — $ 11,263 $ 55,589 $ 87,879 Fuels & emission control (1) 66,095 — — — 66,095 Packaging & engineered plastics 16,636 16,347 17,763 14,086 64,832 Highway safety & construction (1) — — 82,738 22,466 105,204 Consumer products — — — 67,138 67,138 Natural resources 19,611 — 3,616 15,443 38,670 Total segment sales 123,369 16,347 115,380 174,722 429,818 Eliminations (833 ) — 119 (1,901 ) (2,615 ) Total $ 122,536 $ 16,347 $ 115,499 $ 172,821 $ 427,203 Nine months ended September 30, 2018 Refining Services Catalysts Performance Materials Performance Chemicals Total Industrial & process chemicals $ 55,347 $ 54 $ 38,070 $ 186,886 $ 280,357 Fuels & emission control (1) 182,304 — — — 182,304 Packaging & engineered plastics 45,032 50,113 57,247 40,375 192,767 Highway safety & construction (1) — — 198,165 64,930 263,095 Consumer products — — — 209,256 209,256 Natural resources 53,471 — 11,178 46,999 111,648 Total segment sales 336,154 50,167 304,660 548,446 1,239,427 Eliminations (2,456 ) (54 ) (214 ) (8,590 ) (11,314 ) Total $ 333,698 $ 50,113 $ 304,446 $ 539,856 $ 1,228,113 (1) As described in Note 1 , the Company experiences seasonal sales fluctuations to customers in the fuels & emission control and highway safety & construction end uses.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 , and indicates the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. September 30, Quoted Prices in Significant Other Observable Inputs (Level 2) Significant Assets: Derivative contracts (Note 14) $ 40,125 $ — $ 40,125 $ — Restoration plan assets 4,238 4,238 — — Total $ 44,363 $ 4,238 $ 40,125 $ — Liabilities: Derivative contracts (Note 14) $ 4,130 $ — $ 4,130 $ — December 31, Quoted Prices in Significant Other Observable Inputs (Level 2) Significant Assets: Derivative contracts (Note 14) $ 20,768 $ — $ 20,768 $ — Restoration plan assets 4,244 4,244 — — Total $ 25,012 $ 4,244 $ 20,768 $ — Liabilities: Derivative contracts (Note 14) $ 2,026 $ — $ 2,026 $ —

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables present the tax effects of each component of other comprehensive income for the three and nine months ended September 30, 2019 and 2018 : Three months ended September 30, 2019 2018 Pre-tax amount Tax benefit/(expense) After-tax amount Pre-tax amount Tax benefit/(expense) After-tax amount Defined benefit and other postretirement plans: Amortization of net gains and (losses) $ (10 ) $ 4 $ (6 ) $ (50 ) $ 13 $ (37 ) Amortization of prior service cost (63 ) 10 (53 ) (19 ) 4 (15 ) Benefit plans, net (73 ) 14 (59 ) (69 ) 17 (52 ) Net (loss) gain from hedging activities 46 (11 ) 35 494 (124 ) 370 Foreign currency translation (1) (10,020 ) (3,852 ) (13,872 ) 3,391 1,795 5,186 Other comprehensive income (loss) $ (10,047 ) $ (3,849 ) $ (13,896 ) $ 3,816 $ 1,688 $ 5,504 Nine months ended September 30, 2019 2018 Pre-tax amount Tax benefit/(expense) After-tax amount Pre-tax amount Tax benefit/(expense) After-tax amount Defined benefit and other postretirement plans: Amortization of net gains and (losses) $ (26 ) $ 8 $ (18 ) $ 1,798 $ (449 ) $ 1,349 Amortization of prior service cost (128 ) 26 (102 ) (58 ) 14 (44 ) Benefit plans, net (154 ) 34 (120 ) 1,740 (435 ) 1,305 Net (loss) gain from hedging activities (3,579 ) 895 (2,684 ) 4,143 (1,037 ) 3,106 Foreign currency translation (1) 4,731 (5,351 ) (620 ) (16,442 ) 806 (15,636 ) Other comprehensive income (loss) $ 998 $ (4,422 ) $ (3,424 ) $ (10,559 ) $ (666 ) $ (11,225 ) (1) The income tax benefit or expense included in other comprehensive income is attributed to the portion of foreign currency translation associated with the Company’s cross-currency interest rate swaps, for which the tax effect is based on the applicable U.S. deferred income tax rate. See Note 14 to these condensed consolidated financial statements for information regarding the Company’s cross-currency interest rate swaps. The following table presents the changes in accumulated other comprehensive income (loss), net of tax, by component for the nine months ended September 30, 2019 and 2018 : Defined benefit Net gain (loss) from hedging activities Foreign Total December 31, 2018 $ (546 ) $ 637 $ (39,195 ) $ (39,104 ) Other comprehensive loss before reclassifications (27 ) (3,163 ) (665 ) (3,855 ) Amounts reclassified from accumulated other comprehensive income (1) (93 ) 479 — 386 Net current period other comprehensive loss (120 ) (2,684 ) (665 ) (3,469 ) Tax Cuts and Jobs Act, reclassification from AOCI to retained earnings 1,684 190 — 1,874 September 30, 2019 $ 1,018 $ (1,857 ) $ (39,860 ) $ (40,699 ) December 31, 2017 $ 7,412 $ 967 $ (4,068 ) $ 4,311 Other comprehensive income (loss) before reclassifications 1,360 2,906 (16,363 ) (12,097 ) Amounts reclassified from accumulated other comprehensive income (1) (55 ) 200 — 145 Net current period other comprehensive income (loss) 1,305 3,106 (16,363 ) (11,952 ) September 30, 2018 $ 8,717 $ 4,073 $ (20,431 ) $ (7,641 ) (1) See the following table for details about these reclassifications. Amounts in parentheses indicate debits.
Reclassification out of Accumulated Other Comprehensive Income	The following table presents the reclassifications out of accumulated other comprehensive income for the three and nine months ended September 30, 2019 and 2018 : Details about Accumulated Other Comprehensive Income Components Amounts Reclassified from Accumulated Other Comprehensive Income(1) Affected Line Item where Income is Presented Three months ended Nine months ended 2019 2018 2019 2018 Amortization of defined benefit and other postretirement items: Prior service credit (cost) $ 32 $ 40 $ 97 $ 79 Other income (expense) (2) Actuarial gains (losses) 8 (2 ) 26 (5 ) Other income (expense) (2) 40 38 123 74 Total before tax (10 ) (13 ) (30 ) (19 ) Tax expense $ 30 $ 25 $ 93 $ 55 Net of tax Gains and losses on cash flow hedges: Interest rate caps $ (157 ) $ (71 ) $ (449 ) $ (164 ) Interest expense Natural gas swaps (291 ) (30 ) (187 ) (101 ) Cost of goods sold (448 ) (101 ) (636 ) (265 ) Total before tax 111 24 157 65 Tax benefit $ (337 ) $ (77 ) $ (479 ) $ (200 ) Net of tax Total reclassifications for the period $ (307 ) $ (52 ) $ (386 ) $ (145 ) Net of tax (1) Amounts in parentheses indicate debits to profit/loss. (2) These accumulated other comprehensive income (loss) components are components of net periodic pension and other postretirement cost (see Note 16 to these condensed consolidated financial statements for additional details).

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The change in the carrying amount of goodwill for the nine months ended September 30, 2019 is summarized as follows: Refining Services Catalysts Performance Materials Performance Chemicals Total Balance as of December 31, 2018 $ 311,892 $ 77,759 $ 274,947 $ 590,331 $ 1,254,929 Foreign exchange impact — (844 ) 458 (3,247 ) (3,633 ) Balance as of September 30, 2019 $ 311,892 $ 76,915 $ 275,405 $ 587,084 $ 1,251,296

Other Operating Expense, Net (T

Other Operating Expense, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Other Income and Expenses [Abstract]
Schedule of Other Operating (Income) Expense	A summary of other operating expense, net is as follows: Three months ended Nine months ended 2019 2018 2019 2018 Amortization expense $ 8,607 $ 8,711 $ 25,907 $ 26,404 Transaction and other related costs 2,930 215 3,938 827 Net (gain) loss on asset disposals (1) 1,136 5,202 (7,697 ) 11,106 Insurance recoveries (2) — — — (1,557 ) Environmental related costs 1,174 39 2,501 526 Other, net 1,948 2,334 3,704 4,382 $ 15,795 $ 16,501 $ 28,353 $ 41,688 (1) During the nine months ended September 30, 2019 , the Company recognized a gain of $11,362 related to the sale of a product line. Refer to Note 6 of these condensed consolidated financial statements for additional details. (2) During the nine months ended September 30, 2018 , the Company recognized $2,500 of insurance recoveries in its condensed consolidated statements of income related to the Company’s claim for losses sustained during Hurricane Harvey in August 2017. For the nine months ended September 30, 2018 , $1,557 was recorded as a gain in other operating expense, net, as reimbursement of expenses, $207 was recorded as a gain in net loss on asset disposals within other operating expense, net, for the Company’s previously recognized property losses, and $736 represented recoveries in excess of the Company’s property losses which was recorded as a non-operating gain in other expense, net, in the Company’s condensed consolidated statements of income.

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory, Current	Inventories, net, are classified and valued as follows: September 30, December 31, Finished products and work in process $ 206,419 $ 206,188 Raw materials 53,347 58,560 $ 259,766 $ 264,748 Valued at lower of cost or market: LIFO basis $ 155,089 $ 160,863 Valued at lower of cost and net realizable value: FIFO or average cost basis 104,677 103,885 $ 259,766 $ 264,748

Investments in Affiliated Com_2

Investments in Affiliated Companies (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 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% Asociacion para el Estudio de las Tecnologias de Equipamiento de Carreteras, S.A. (“Aetec”) Spain 20% Following is summarized information of the combined investments (1) : Three months ended Nine months ended 2019 2018 2019 2018 Sales $ 121,471 $ 74,088 $ 279,503 $ 271,562 Gross profit 48,416 24,495 102,966 100,686 Operating income 37,958 14,594 74,217 72,257 Net income 37,852 14,545 75,002 72,204 (1) Summarized information of the combined investments is presented at 100%; the Company’s share of the net assets and net income of affiliates is calculated based on the percent ownership specified in the table above.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2019
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, December 31, Land $ 189,234 $ 190,772 Buildings 219,380 212,284 Machinery and equipment 1,162,273 1,125,117 Construction in progress 111,984 102,185 1,682,871 1,630,358 Less: accumulated depreciation (504,392 ) (421,379 ) $ 1,178,479 $ 1,208,979

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Schedule of Right-of-Use Lease Assets and Lease Liabilities	The table below presents the operating and finance right-of-use lease assets and lease liabilities recognized on the condensed consolidated balance sheet as of September 30, 2019 : Classification September 30, Assets Operating lease assets Right-of-use lease assets $ 54,238 Finance lease assets Property, plant and equipment, net 1,582 Total leased assets $ 55,820 Liabilities Current: Operating lease liabilities Operating lease liabilities—current $ 14,095 Finance lease liabilities Accrued liabilities 176 Noncurrent: Operating lease liabilities Operating lease liabilities—noncurrent 38,473 Finance lease liabilities Other long-term liabilities 364 Total lease liabilities $ 53,108
Weighted Average Remaining Lease Term and Discount Rate	The Company’s weighted average remaining lease term and weighted average discount rate for operating leases as of September 30, 2019 are as follows: September 30, Weighted average remaining lease term (in years): Operating leases 5.86 Finance leases 2.90 Weighted average discount rate: Operating leases 5.74 % Finance leases 4.67 %
Maturities of Lease Liabilities	Maturities of lease liabilities as of September 30, 2019 are as follows: Operating Leases Finance Leases Remainder of 2019 $ 16,522 $ 47 2020 13,198 201 2021 9,816 201 2022 7,256 123 2023 4,767 3 Thereafter 11,395 — Total lease payments 62,954 575 Less: Interest (10,386 ) (35 ) Total lease liabilities (1) $ 52,568 $ 540 (1) Refer to the above table regarding the Company’s right-of-use lease assets and lease liabilities for the presentation of the lease liabilities in the Company’s condensed consolidated balance sheet at September 30, 2019 .
Schedule of Future Minimum Rental Payments for Operating Leases	At December 31, 2018 , future minimum payments under non-cancelable operating leases under previous lease guidance was as follows: Year Amount 2019 $ 18,457 2020 14,344 2021 11,432 2022 8,354 2023 6,198 Thereafter 17,477 $ 76,262
Cash Flow Information Related to Leases	The following table presents other information related to our operating and finance leases and the impact on the Company’s condensed consolidated statement of cash flows: Nine months ended Cash paid for amounts included in the measurement of lease liabilities: Payments on operating leases included in operating cash flows $ 12,158 Interest payments under finance lease obligations included in operating cash flows 29 Principal payments under finance lease obligations included in financing cash flows 169 Right-of-use assets obtained in exchange for new lease liabilities (non-cash): Operating leases 5,148 Finance leases —

Long-term Debt (Tables)

Long-term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The summary of long-term debt is as follows: September 30, December 31, 2018 Term Loan Facility $ 1,057,497 $ 1,157,498 6.75% Senior Secured Notes due 2022 625,000 625,000 5.75% Senior Unsecured Notes due 2025 295,000 300,000 ABL Facility — — Other 65,778 65,925 Total debt 2,043,275 2,148,423 Original issue discount (15,331 ) (18,584 ) Deferred financing costs (13,017 ) (15,882 ) Total debt, net of original issue discount and deferred financing costs 2,014,927 2,113,957 Less: current portion (8,210 ) (7,237 ) Total long-term debt, excluding current portion $ 2,006,717 $ 2,106,720

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivatives Held	The fair values of derivative instruments held as of September 30, 2019 and December 31, 2018 are shown below: Balance sheet location September 30, 2019 December 31, 2018 Derivative assets: Derivatives designated as cash flow hedges: Natural gas swaps Prepaid and other current assets $ — $ 21 Interest rate caps Prepaid and other current assets — 1,358 Interest rate caps Other long-term assets — 546 — 1,925 Derivatives designed as net investment hedges: Cross-currency interest rate swaps Prepaid and other current assets 7,517 5,499 Cross-currency interest rate swaps Other long-term assets 32,608 13,344 40,125 18,843 Total derivative assets $ 40,125 $ 20,768 Derivative liabilities: Derivatives designated as cash flow hedges: Natural gas swaps Accrued liabilities $ 626 $ 36 Natural gas swaps Other long-term liabilities 302 148 Interest rate caps Other long-term liabilities 3,202 1,842 Total derivative liabilities $ 4,130 $ 2,026
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 cash flow hedges on AOCI for the three and nine months ended September 30, 2019 and 2018 : Three months ended September 30, 2019 2018 Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Interest rate caps Interest (expense) income $ (216 ) $ (157 ) $ (93 ) $ (71 ) Natural gas swaps Cost of goods sold (185 ) (291 ) (300 ) (30 ) $ (401 ) $ (448 ) $ (393 ) $ (101 ) Nine months ended September 30, 2019 2018 Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Interest rate caps Interest (expense) income $ (3,264 ) $ (449 ) $ (3,396 ) $ (164 ) Natural gas swaps Cost of goods sold (951 ) (187 ) (482 ) (101 ) $ (4,215 ) $ (636 ) $ (3,878 ) $ (265 )
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss)	The following tables show the effect of the Company’s cash flow hedge accounting on the condensed consolidated statements of income for the three and nine months ended September 30, 2019 and 2018 : Location and amount of gain (loss) recognized in income on cash flow hedging relationships Three months ended September 30, 2019 2018 Cost of goods sold Interest (expense) income Cost of goods sold Interest (expense) income Total amounts of income and expense line items presented in the statement of income in which the effects of cash flow hedges are recorded $ (310,904 ) $ (27,697 ) $ (319,703 ) $ (28,238 ) The effects of cash flow hedging: Gain (loss) on cash flow hedging relationships: Interest contracts: Amount of gain (loss) reclassified from AOCI into income — (157 ) — (71 ) Commodity contracts: Amount of gain (loss) reclassified from AOCI into income (291 ) — (30 ) — Location and amount of gain (loss) recognized in income on cash flow hedging relationships Nine months ended September 30, 2019 2018 Cost of goods sold Interest (expense) income Cost of goods sold Interest (expense) income Total amounts of income and expense line items presented in the statement of income in which the effects of cash flow hedges are recorded (905,395 ) (84,855 ) (934,088 ) (84,622 ) The effects of cash flow hedging: Gain (loss) on cash flow hedging relationships: Interest contracts: Amount of gain (loss) reclassified from AOCI into income — (449 ) — (164 ) Commodity contracts: Amount of gain (loss) reclassified from AOCI into income (187 ) — (101 ) —
Schedule of Net Investment Hedges in Accumulated Other Comprehensive Income (Loss)	The following tables show the effect of the Company’s net investment hedges on AOCI and the condensed consolidated statements of income for the three and nine months ended September 30, 2019 and 2018 : Amount of gain (loss) recognized in OCI on derivative Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) reclassified from AOCI into income Location of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Three months ended September 30, Three months ended September 30, Three months ended September 30, 2019 2018 2019 2018 2019 2018 Cross-currency interest rate swaps $ 15,342 $ 1,138 Gain (loss) on sale of subsidiary $ — $ — Interest (expense) income $ 2,395 $ 2,271 Amount of gain (loss) recognized in OCI on derivative Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) reclassified from AOCI into income Location of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing) Nine months ended Nine months ended Nine months ended 2019 2018 2019 2018 2019 2018 Cross-currency interest rate swaps $ 21,282 $ 8,799 Gain (loss) on sale of subsidiary $ — $ — Interest (expense) income $ 6,888 $ 5,662

Benefit Plans (Tables)

Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2019
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure
Components of Net Periodic Expense	Components of net periodic expense (benefit) are as follows: Defined Benefit Pension Plans U.S. Foreign Three months ended Three months ended 2019 2018 2019 2018 Service cost $ 251 $ 243 $ 780 $ 933 Interest cost 2,653 2,395 801 (601 ) Expected return on plan assets (2,912 ) (3,165 ) (782 ) 453 Amortization of net loss — — 1 13 Amortization of prior service cost — — 6 — Net periodic expense (benefit) $ (8 ) $ (527 ) $ 806 $ 798 U.S. Foreign Nine months ended Nine months ended 2019 2018 2019 2018 Service cost $ 751 $ 776 $ 2,464 $ 2,665 Interest cost 7,958 7,137 2,458 2,512 Expected return on plan assets (8,733 ) (9,515 ) (2,375 ) (2,494 ) Amortization of net loss — — 1 38 Amortization of prior service cost — — 18 — Curtailment gain recognized — (576 ) — — Net periodic expense (benefit) $ (24 ) $ (2,178 ) $ 2,566 $ 2,721
Supplemental Retirement Plans
Defined Benefit Plan Disclosure
Components of Net Periodic Expense	Supplemental Retirement Plans Three months ended Nine months ended 2019 2018 2019 2018 Interest cost $ 121 $ 110 $ 364 $ 330 Net periodic expense $ 121 $ 110 $ 364 $ 330
Other Postretirement Benefits Plans
Defined Benefit Plan Disclosure
Components of Net Periodic Expense	Other Postretirement Benefit Plans Three months ended Nine months ended 2019 2018 2019 2018 Service cost $ 3 $ 3 $ 10 $ 12 Interest cost 38 43 114 108 Amortization of prior service credit (32 ) (40 ) (97 ) (79 ) Amortization of net gain (9 ) (11 ) (27 ) (33 ) Net periodic expense (benefit) $ — $ (5 ) $ — $ 8

Reportable Segments (Tables)

Reportable Segments (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Reconciliation of Revenue from Reportable Segments to Consolidated	Summarized financial information for the Company’s reportable segments is shown in the following table: Three months ended Nine months ended 2019 2018 2019 2018 Sales: Refining Services $ 118,335 $ 123,369 $ 341,469 $ 336,154 Catalysts (1) 25,612 16,347 62,335 50,167 Performance Materials 115,134 115,380 295,095 304,660 Performance Chemicals 167,949 174,722 526,239 548,446 Eliminations (2) (3,229 ) (2,615 ) (10,441 ) (11,314 ) Total $ 423,801 $ 427,203 $ 1,214,697 $ 1,228,113 Segment Adjusted EBITDA: (3) Refining Services $ 51,166 $ 49,559 $ 133,721 $ 126,368 Catalysts (4) 31,638 15,751 79,372 62,227 Performance Materials 25,769 21,255 65,505 61,880 Performance Chemicals 36,804 41,832 120,642 131,748 Total Segment Adjusted EBITDA (5) $ 145,377 $ 128,397 $ 399,240 $ 382,223 (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 $54,414 and $32,297 for the three months ended September 30, 2019 and 2018 , respectively. The proportionate share of sales is $123,016 and $120,159 for the nine months ended September 30, 2019 and 2018 , respectively. (2) The Company eliminates intersegment sales when reconciling to the Company’s condensed consolidated statements of income. (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 Catalysts segment is $22,628 for the three months ended September 30, 2019 , which includes $17,248 of equity in net income plus $1,658 of amortization of investment in affiliate step-up and $3,722 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Catalysts segment is $10,513 for the three months ended September 30, 2018 , which includes $5,563 of equity in net income plus $1,658 of amortization of investment in affiliate step-up and $3,292 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Catalysts segment is $48,621 for the nine months ended September 30, 2019 , which includes $31,548 of equity in net income plus $5,875 of amortization of investment in affiliate step-up and $11,198 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Catalysts segment is $45,194 for the nine months ended September 30, 2018 , which includes $31,005 of equity in net income plus $4,975 of amortization of investment in affiliate step-up and $9,214 of joint venture depreciation, amortization and interest. (5)
Reconciliation of Net Income to Segment Adjusted EBITDA	A reconciliation of net income attributable to PQ Group Holdings to Segment Adjusted EBITDA is as follows: Three months ended Nine months ended 2019 2018 2019 2018 Reconciliation of net income attributable to PQ Group Holdings Inc. to Segment Adjusted EBITDA Net income attributable to PQ Group Holdings Inc. $ 26,713 $ 14,185 $ 60,438 $ 30,181 Provision for income taxes 16,718 8,470 39,472 21,590 Interest expense, net 27,697 28,238 84,855 84,622 Depreciation and amortization 44,246 43,827 135,230 139,298 Segment EBITDA 115,374 94,720 319,995 275,691 Unallocated corporate expenses 7,693 10,276 28,062 27,322 Joint venture depreciation, amortization and interest 3,722 3,292 11,198 9,214 Amortization of investment in affiliate step-up 1,658 1,658 5,875 4,975 Amortization of inventory step-up — — — 1,603 Debt extinguishment costs 1,767 864 1,767 6,743 Net (gain) loss on asset disposals 1,136 5,202 (7,697 ) 11,106 Foreign currency exchange loss 4,457 3,527 5,380 15,347 LIFO expense 534 856 10,814 5,903 Transaction and other related costs 670 210 1,725 895 Equity-based compensation 4,806 4,252 13,576 11,879 Restructuring, integration and business optimization expenses 717 2,178 1,436 5,662 Defined benefit pension plan cost 834 112 2,379 260 Other 2,009 1,250 4,730 5,623 Segment Adjusted EBITDA $ 145,377 $ 128,397 $ 399,240 $ 382,223

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Stock-Based Compensation [Abstract]
Schedule of Nonvested Restricted Stock and Performance Stock Unit Activity	The following table summarizes the activity for the Company’s restricted stock units and performance stock units for the nine months ended September 30, 2019 : Restricted Stock Units Performance Stock Units Number of Weighted Average Grant Date Fair Value (per share) Number of Weighted Average Grant Date Fair Value (per share) Nonvested as of December 31, 2018 998,786 $ 16.83 — $ — Granted 1,245,628 $ 15.42 550,676 $ 15.41 Vested (148,551 ) $ 15.90 — $ — Forfeited (20,837 ) $ 16.00 — $ — Nonvested as of September 30, 2019 2,075,026 $ 16.06 550,676 $ 15.41

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Reconciliation 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 2019 2018 2019 2018 Weighted average shares outstanding – Basic 134,511,819 133,336,352 134,213,571 133,237,653 Dilutive effect of unvested common shares and restricted stock units with service conditions, performance stock units considered probable of vesting and assumed stock option exercises and conversions 1,137,891 1,239,810 1,091,799 985,975 Weighted average shares outstanding – Diluted 135,649,710 134,576,162 135,305,370 134,223,628
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted earnings per share are calculated as follows: Three months ended Nine months ended 2019 2018 2019 2018 Numerator: Net income attributable to PQ Group Holdings Inc. $ 26,713 $ 14,185 $ 60,438 $ 30,181 Denominator: Weighted average shares outstanding – Basic 134,511,819 133,336,352 134,213,571 133,237,653 Weighted average shares outstanding – Diluted 135,649,710 134,576,162 135,305,370 134,223,628 Net income per share: Basic income per share $ 0.20 $ 0.11 $ 0.45 $ 0.23 Diluted income per share $ 0.20 $ 0.11 $ 0.45 $ 0.22
Schedule of Securities Excluded from Computation of Earnings Per Share	The table below presents the details of the Company’s weighted average equity-based awards outstanding during each respective period that were excluded from the calculation of diluted earnings per share: Three months ended Nine months ended 2019 2018 2019 2018 Restricted stock awards with performance only targets not yet achieved 1,537,572 1,709,463 1,601,474 1,719,775 Stock options with performance only targets not yet achieved 578,564 586,253 583,204 586,253 Anti-dilutive restricted stock awards, restricted stock units and performance stock units — — — 18,076 Anti-dilutive stock options 863,063 760,766 863,063 668,596

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	The following table presents supplemental cash flow information for the Company: Nine months ended 2019 2018 Cash paid during the period for: Income taxes, net of refunds $ 13,261 $ 16,121 Interest (1) 82,349 83,612 Non-cash investing activity (2) : Capital expenditures acquired on account but unpaid as of the period end 13,265 10,624 (1) Excludes capitalized interest for the periods presented, as well as $8,435 and $4,279 of net interest proceeds on swaps designated as net investment hedges for the nine months ended September 30, 2019 and 2018 , respectively, all of which is included within cash flows from investing activities in the Company’s condensed consolidated statements of cash flows. (2) For the supplemental non-cash information on lease liabilities arising from obtaining right-of-use lease assets, see Note 12 to these condensed consolidated financial statements for additional details.
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets as of September 30, 2019 and 2018 to the total of the same amounts shown in the condensed consolidated statements of cash flows for the nine months then ended: September 30, 2019 2018 Cash and cash equivalents $ 78,510 $ 56,684 Restricted cash included in prepaid and other current assets 1,745 1,333 Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows $ 80,255 $ 58,017
Restrictions on Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets as of September 30, 2019 and 2018 to the total of the same amounts shown in the condensed consolidated statements of cash flows for the nine months then ended: September 30, 2019 2018 Cash and cash equivalents $ 78,510 $ 56,684 Restricted cash included in prepaid and other current assets 1,745 1,333 Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows $ 80,255 $ 58,017

Background and Basis of Prese_3

Background and Basis of Presentation (Details)	Mar. 01, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	4	2
Number of operating segments	4	2
Number of reporting units	4	4

New Accounting Standards (Detai

New Accounting Standards (Details) $ in Thousands	Jan. 01, 2019USD ($)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating and finance leases, right-of-use asset	$ 60,726
Operating and finance leases, right-of-use asset, lease commitments	57,832
Operating and finance lease, right-of-use asset, favorable lease agreement intangible asset reclassification	2,895
Operating and finance lease, liability	58,929
Accounting Standards Update 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax Cuts and Jobs Act, reclassification from AOCI to retained earnings	$ 1,874

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregated Revenue
Sales	$ 423,801	$ 427,203	$ 1,214,697	$ 1,228,113
Refining Services
Disaggregated Revenue
Sales	117,522	122,536	338,874	333,698
Catalysts
Disaggregated Revenue
Sales	25,565	16,347	62,226	50,113
Performance Materials
Disaggregated Revenue
Sales	115,116	115,499	294,925	304,446
Performance Chemicals
Disaggregated Revenue
Sales	165,598	172,821	518,672	539,856
Operating segments
Disaggregated Revenue
Sales	427,030	429,818	1,225,138	1,239,427
Operating segments | Industrial & process chemicals
Disaggregated Revenue
Sales	87,148	87,879	273,640	280,357
Operating segments | Fuels & emission control
Disaggregated Revenue
Sales	70,048	66,095	191,243	182,304
Operating segments | Packaging & engineered plastics
Disaggregated Revenue
Sales	66,696	64,832	194,163	192,767
Operating segments | Highway safety & construction
Disaggregated Revenue
Sales	103,302	105,204	260,155	263,095
Operating segments | Consumer products
Disaggregated Revenue
Sales	64,849	67,138	198,798	209,256
Operating segments | Natural resources
Disaggregated Revenue
Sales	34,987	38,670	107,139	111,648
Operating segments | Refining Services
Disaggregated Revenue
Sales	118,335	123,369	341,469	336,154
Operating segments | Refining Services | Industrial & process chemicals
Disaggregated Revenue
Sales	20,180	21,027	60,485	55,347
Operating segments | Refining Services | Fuels & emission control
Disaggregated Revenue
Sales	70,048	66,095	191,243	182,304
Operating segments | Refining Services | Packaging & engineered plastics
Disaggregated Revenue
Sales	12,197	16,636	38,953	45,032
Operating segments | Refining Services | Highway safety & construction
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Refining Services | Consumer products
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Refining Services | Natural resources
Disaggregated Revenue
Sales	15,910	19,611	50,788	53,471
Operating segments | Catalysts
Disaggregated Revenue
Sales	25,612	16,347	62,335	50,167
Operating segments | Catalysts | Industrial & process chemicals
Disaggregated Revenue
Sales	47	0	109	54
Operating segments | Catalysts | Fuels & emission control
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Catalysts | Packaging & engineered plastics
Disaggregated Revenue
Sales	25,565	16,347	62,226	50,113
Operating segments | Catalysts | Highway safety & construction
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Catalysts | Consumer products
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Catalysts | Natural resources
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Performance Materials
Disaggregated Revenue
Sales	115,134	115,380	295,095	304,660
Operating segments | Performance Materials | Industrial & process chemicals
Disaggregated Revenue
Sales	12,225	11,263	38,037	38,070
Operating segments | Performance Materials | Fuels & emission control
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Performance Materials | Packaging & engineered plastics
Disaggregated Revenue
Sales	16,886	17,763	51,863	57,247
Operating segments | Performance Materials | Highway safety & construction
Disaggregated Revenue
Sales	82,502	82,738	195,119	198,165
Operating segments | Performance Materials | Consumer products
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Performance Materials | Natural resources
Disaggregated Revenue
Sales	3,521	3,616	10,076	11,178
Operating segments | Performance Chemicals
Disaggregated Revenue
Sales	167,949	174,722	526,239	548,446
Operating segments | Performance Chemicals | Industrial & process chemicals
Disaggregated Revenue
Sales	54,696	55,589	175,009	186,886
Operating segments | Performance Chemicals | Fuels & emission control
Disaggregated Revenue
Sales	0	0	0	0
Operating segments | Performance Chemicals | Packaging & engineered plastics
Disaggregated Revenue
Sales	12,048	14,086	41,121	40,375
Operating segments | Performance Chemicals | Highway safety & construction
Disaggregated Revenue
Sales	20,800	22,466	65,036	64,930
Operating segments | Performance Chemicals | Consumer products
Disaggregated Revenue
Sales	64,849	67,138	198,798	209,256
Operating segments | Performance Chemicals | Natural resources
Disaggregated Revenue
Sales	15,556	15,443	46,275	46,999
Inter-segment sales eliminations
Disaggregated Revenue
Sales	(3,229)	(2,615)	(10,441)	(11,314)
Inter-segment sales eliminations | Refining Services
Disaggregated Revenue
Sales	(813)	(833)	(2,595)	(2,456)
Inter-segment sales eliminations | Catalysts
Disaggregated Revenue
Sales	(47)	0	(109)	(54)
Inter-segment sales eliminations | Performance Materials
Disaggregated Revenue
Sales	(18)	119	(170)	(214)
Inter-segment sales eliminations | Performance Chemicals
Disaggregated Revenue
Sales	$ (2,351)	$ (1,901)	$ (7,567)	$ (8,590)

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Contract with Customer, Asset and Liability [Abstract]
Contract assets	$ 0	$ 0
Contract liabilities	9,000	$ 0
Deferred revenue	7,965
Revenue recognized	$ (1,035)

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, 2019	Dec. 31, 2018
Assets:
Derivative contracts	$ 40,125	$ 20,768
Restoration plan assets	4,238	4,244
Total	44,363	25,012
Liabilities:
Derivative contracts	4,130	2,026
Quoted Prices in Active Markets (Level 1)
Assets:
Derivative contracts	0	0
Restoration plan assets	4,238	4,244
Total	4,238	4,244
Liabilities:
Derivative contracts	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Derivative contracts	40,125	20,768
Restoration plan assets	0	0
Total	40,125	20,768
Liabilities:
Derivative contracts	4,130	2,026
Significant Unobservable Inputs (Level 3)
Assets:
Derivative contracts	0	0
Restoration plan assets	0	0
Total	0	0
Liabilities:
Derivative contracts	$ 0	$ 0

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income - Pre-tax and After-tax Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
After-tax amount
Pre-tax amount	$ (10,047)			$ 3,816			$ 998	$ (10,559)
Tax benefit/(expense)	(3,849)			1,688			(4,422)	(666)
Total other comprehensive income (loss)	(13,896)	$ 4,887	$ 5,585	5,504	$ (27,565)	$ 10,836	(3,424)	(11,225)
Amortization of net gains and (losses)
After-tax amount
Pre-tax amount	(10)			(50)			(26)	1,798
Tax benefit/(expense)	4			13			8	(449)
Total other comprehensive income (loss)	(6)			(37)			(18)	1,349
Amortization of prior service cost
After-tax amount
Pre-tax amount	(63)			(19)			(128)	(58)
Tax benefit/(expense)	10			4			26	14
Total other comprehensive income (loss)	(53)			(15)			(102)	(44)
Benefit plans, net
After-tax amount
Pre-tax amount	(73)			(69)			(154)	1,740
Tax benefit/(expense)	14			17			34	(435)
Total other comprehensive income (loss)	(59)			(52)			(120)	1,305
Net (loss) gain from hedging activities
After-tax amount
Pre-tax amount	46			494			(3,579)	4,143
Tax benefit/(expense)	(11)			(124)			895	(1,037)
Total other comprehensive income (loss)	35			370			(2,684)	3,106
Foreign currency translation
After-tax amount
Pre-tax amount	(10,020)			3,391			4,731	(16,442)
Tax benefit/(expense)	(3,852)			1,795			(5,351)	806
Total other comprehensive income (loss)	$ (13,872)			$ 5,186			$ (620)	$ (15,636)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income - Change by Component (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,659,560
Ending balance	1,731,646
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(39,104)	$ 4,311
Other comprehensive loss before reclassifications	(3,855)	(12,097)
Amounts reclassified from accumulated other comprehensive income	386	145
Net current period other comprehensive loss	(3,469)	(11,952)
Tax Cuts and Jobs Act, reclassification from AOCI to retained earnings	1,874
Ending balance	(40,699)	(7,641)
Defined benefit and other postretirement plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(546)	7,412
Other comprehensive loss before reclassifications	(27)	1,360
Amounts reclassified from accumulated other comprehensive income	(93)	(55)
Net current period other comprehensive loss	(120)	1,305
Tax Cuts and Jobs Act, reclassification from AOCI to retained earnings	1,684
Ending balance	1,018	8,717
Net gain (loss) from hedging activities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	637	967
Other comprehensive loss before reclassifications	(3,163)	2,906
Amounts reclassified from accumulated other comprehensive income	479	200
Net current period other comprehensive loss	(2,684)	3,106
Tax Cuts and Jobs Act, reclassification from AOCI to retained earnings	190
Ending balance	(1,857)	4,073
Foreign currency translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(39,195)	(4,068)
Other comprehensive loss before reclassifications	(665)	(16,363)
Amounts reclassified from accumulated other comprehensive income	0	0
Net current period other comprehensive loss	(665)	(16,363)
Tax Cuts and Jobs Act, reclassification from AOCI to retained earnings	0
Ending balance	$ (39,860)	$ (20,431)

Accumulated Other Comprehensi_5

Accumulated Other Comprehensive Income - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other expense, net	$ 1,834			$ 2,451			$ 1,890	$ 13,114
Interest expense, net	27,697			28,238			84,855	84,622
Cost of goods sold	310,904			319,703			905,395	934,088
Income before income taxes and noncontrolling interest	(43,537)			(22,906)			(100,451)	(52,741)
Tax benefit (expense)	16,718			8,470			39,472	21,590
Net income	(26,819)	$ (30,719)	$ (3,441)	(14,436)	$ (16,159)	$ (556)	(60,979)	(31,151)
Amount of gain (loss) reclassified from AOCI into income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(307)			(52)			(386)	(145)
Defined benefit and other postretirement plans | Amount of gain (loss) reclassified from AOCI into income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes and noncontrolling interest	40			38			123	74
Tax benefit (expense)	(10)			(13)			(30)	(19)
Net income	30			25			93	55
Prior service credit (cost) | Amount of gain (loss) reclassified from AOCI into income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other expense, net	32			40			97	79
Actuarial gains (losses) | Amount of gain (loss) reclassified from AOCI into income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other expense, net	8			(2)			26	(5)
Net gain (loss) from hedging activities | Amount of gain (loss) reclassified from AOCI into income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes and noncontrolling interest	(448)			(101)			(636)	(265)
Tax benefit (expense)	111			24			157	65
Net income	(337)			(77)			(479)	(200)
Net gain (loss) from hedging activities | Amount of gain (loss) reclassified from AOCI into income | Interest rate caps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	(157)			(71)			(449)	(164)
Net gain (loss) from hedging activities | Amount of gain (loss) reclassified from AOCI into income | Natural gas swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	$ (291)			$ (30)			$ (187)	$ (101)

Sale of Product Line (Details)

Sale of Product Line (Details) - USD ($) $ in Thousands	Jun. 28, 2019	Sep. 30, 2019	Dec. 31, 2018
Sale of Product Line [Line Items]
Property, plant and equipment, net		$ 1,178,479	$ 1,208,979
Sulfate Salts Product Line | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Sale of Product Line [Line Items]
Consideration for sale of product line	$ 28,000
Pre-tax gain on sale	11,362
Net working capital	4,215
Property, plant and equipment, net	3,423
Deferred revenue	$ 9,000

Goodwill (Details)

Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Goodwill
Beginning balance	$ 1,254,929
Foreign exchange impact	(3,633)
Ending balance	1,251,296
Refining Services
Goodwill
Beginning balance	311,892
Foreign exchange impact	0
Ending balance	311,892
Catalysts
Goodwill
Beginning balance	77,759
Foreign exchange impact	(844)
Ending balance	76,915
Performance Materials
Goodwill
Beginning balance	274,947
Foreign exchange impact	458
Ending balance	275,405
Performance Chemicals
Goodwill
Beginning balance	590,331
Foreign exchange impact	(3,247)
Ending balance	$ 587,084

Other Operating Expense, Net (D

Other Operating Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Income and Expenses [Abstract]
Amortization expense	$ 8,607	$ 8,711	$ 25,907	$ 26,404
Transaction and other related costs	2,930	215	3,938	827
Net (gain) loss on asset disposals	1,136	5,202	(7,697)	11,106
Insurance recoveries	0	0	0	(1,557)
Environmental related costs	1,174	39	2,501	526
Other, net	1,948	2,334	3,704	4,382
Other operating expense, net	$ 15,795	$ 16,501	$ 28,353	41,688
Total gain related to insurance recoveries				2,500
Insurance recoveries recorded as gain on asset disposals				207
Insurance recoveries recorded as non-operating income				$ 736

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Inventory, Net
Finished products and work in process	$ 206,419	$ 206,188
Raw materials	53,347	58,560
Inventories, net	259,766	264,748
Valued at lower of cost or market:
LIFO basis	155,089	160,863
Valued at lower of cost and net realizable value:
FIFO or average cost basis	104,677	103,885
Inventories, net	$ 259,766	$ 264,748

Investments in Affiliated Com_3

Investments in Affiliated Companies - Ownership Percentage (Details)	Sep. 30, 2019
PQ Silicates Ltd.
Schedule of Equity Method Investments
Ownership percentage	50.00%
Zeolyst International
Schedule of Equity Method Investments
Ownership percentage	50.00%
Zeolyst C.V.
Schedule of Equity Method Investments
Ownership percentage	50.00%
Quaker Holdings
Schedule of Equity Method Investments
Ownership percentage	49.00%
Asociacion para el Estudio de las Tecnologias de Equipamiento de Carreteras, S.A. (“Aetec”)
Schedule of Equity Method Investments
Ownership percentage	20.00%

Investments in Affiliated Com_4

Investments in Affiliated Companies - Summarized Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity Method Investment, Summarized Financial Information
Sales	$ 121,471	$ 74,088	$ 279,503	$ 271,562
Gross profit	48,416	24,495	102,966	100,686
Operating income	37,958	14,594	74,217	72,257
Net income	$ 37,852	$ 14,545	$ 75,002	$ 72,204

Investments in Affiliated Com_5

Investments in Affiliated Companies - Narratives (Details) - Business Combination - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Business Combination
Net purchase accounting fair value adjustments	$ 252,190		$ 252,190		$ 258,066
Amortization of investment in affiliate step-up	$ 1,658	$ 1,658	$ 5,875	$ 4,975

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment
Property, plant and equipment, gross	$ 1,682,871	$ 1,630,358
Less: accumulated depreciation	(504,392)	(421,379)
Property, plant and equipment, net	1,178,479	1,208,979
Land
Property, Plant and Equipment
Property, plant and equipment, gross	189,234	190,772
Buildings
Property, Plant and Equipment
Property, plant and equipment, gross	219,380	212,284
Machinery and equipment
Property, Plant and Equipment
Property, plant and equipment, gross	1,162,273	1,125,117
Construction in progress
Property, Plant and Equipment
Property, plant and equipment, gross	$ 111,984	$ 102,185

Property, Plant and Equipment -

Property, Plant and Equipment - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Depreciation	$ 31,554	$ 30,626	$ 97,088	$ 99,491

Leases - Narratives (Details)

Leases - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases
Operating lease costs	$ 4,858	$ 14,217
Maximum
Leases
Remaining lease term		30 years

Leases - Right-of-Use Lease Ass

Leases - Right-of-Use Lease Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets
Operating lease assets	$ 54,238	$ 0
Finance lease assets	1,582
Total leased assets	55,820
Current:
Operating lease liabilities	14,095	0
Finance lease liabilities	176
Noncurrent:
Operating lease liabilities	38,473	$ 0
Finance lease liabilities	364
Total lease liabilities	$ 53,108
Finance lease assets, balance sheet line item	us-gaap:PropertyPlantAndEquipmentNet
Finance lease liabilities, current, balance sheet line item	us-gaap:AccruedLiabilitiesCurrent
Finance lease liabilities, noncurrent, balance sheet line item	us-gaap:OtherLiabilitiesNoncurrent

Leases - Remaining Average Weig

Leases - Remaining Average Weighted Average Lease Term and Discount Rate (Details)	Sep. 30, 2019
Weighted average remaining lease term (in years):
Operating leases	5 years 10 months 9 days
Finance leases	2 years 10 months 24 days
Weighted average discount rate:
Operating leases	5.74%
Finance leases	4.67%

Leases - Lease Maturity Schedul

Leases - Lease Maturity Schedule - ASC 842 (Details) $ in Thousands	Sep. 30, 2019USD ($)
Operating Leases
Remainder of 2019	$ 16,522
2020	13,198
2021	9,816
2022	7,256
2023	4,767
Thereafter	11,395
Total lease payments	62,954
Less: Interest	(10,386)
Total lease liabilities	52,568
Finance Leases
Remainder of 2019	47
2020	201
2021	201
2022	123
2023	3
Thereafter	0
Total lease payments	575
Less: Interest	35
Total lease liabilities	$ 540

Leases - Lease Maturity Sched_2

Leases - Lease Maturity Schedule - ASC 840 (Details)	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 18,457
2020	14,344
2021	11,432
2022	8,354
2023	6,198
Thereafter	17,477
Total	$ 76,262

Leases - Other Lease Informatio

Leases - Other Lease Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Cash paid for amounts included in the measurement of lease liabilities: [Abstract]
Payments on operating leases included in operating cash flows	$ 12,158
Interest payments under finance lease obligations included in operating cash flows	29
Principal payments under finance lease obligations included in financing cash flows	169
Right-of-use assets obtained in exchange for new lease liabilities (non-cash):
Operating leases	5,148
Finance leases	$ 0

Long-term Debt (Details)

Long-term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument
Total debt	$ 2,043,275	$ 2,148,423
Original issue discount	(15,331)	(18,584)
Deferred financing costs	(13,017)	(15,882)
Total debt, net of original issue discount and deferred financing costs	2,014,927	2,113,957
Less: current portion	(8,210)	(7,237)
Total long-term debt, excluding current portion	2,006,717	2,106,720
Term Loan Facility
Debt Instrument
Total debt	1,057,497	1,157,498
Senior Notes | 6.75% Senior Secured Notes due 2022
Debt Instrument
Total debt	625,000	625,000
Senior Notes | 5.75% Senior Unsecured Notes due 2025
Debt Instrument
Total debt	295,000	300,000
ABL Facility
Debt Instrument
Total debt	0	0
Other
Debt Instrument
Total debt	$ 65,778	$ 65,925

Long-term Debt - Narratives (De

Long-term Debt - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Term Loan Facility
Debt Instrument
Principal repayment of Term Loan Facility	$ 100,000
Debt extinguishment costs, write-off of deferred financing costs	502
Debt extinguishment costs, write-off of original issue discount	1,181
Term Loan And Senior Notes
Debt Instrument
Long-term debt, fair value	$ 2,009,555	$ 2,010,023

Financial Instruments - Narrati

Financial Instruments - Narratives (Details) € in Thousands, $ in Thousands, MMBTU in Millions	1 Months Ended	9 Months Ended
	Jul. 31, 2016USD ($)	Sep. 30, 2019USD ($)MMBTU	Nov. 30, 2018USD ($)	Feb. 28, 2018EUR (€)
Cash flow hedging
Derivative
Amount of derivative loss expected to be transferred from OCI		$ 1,431
Cash flow hedging | Natural gas swaps
Derivative
Derivative, notional quantity | MMBTU		3.3
Cash flow hedging | July 2016 interest rate caps
Derivative
Premium paid to acquire derivative instrument	$ 1,551
Derivative, cap interest rate		3.00%
Derivative, notional amount	$ 1,000,000
Cash flow hedging | July 2016 interest rate caps | Minimum
Derivative
Derivative, cap interest rate	1.50%
Cash flow hedging | July 2016 interest rate caps | Maximum
Derivative
Derivative, cap interest rate	3.00%
Cash flow hedging | November 2018 interest rate caps
Derivative
Derivative, cap interest rate			3.50%
Derivative, notional amount			$ 500,000
Net investment hedging | Cross-currency interest rate swaps
Derivative
Derivative, notional amount		$ 306,345		€ 280,000

Financial Instruments - Fair Va

Financial Instruments - Fair Value (Details) - Derivatives designated as hedging instrument - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative assets:
Total derivative assets	$ 40,125	$ 20,768
Derivative liabilities:
Total derivative liabilities	4,130	2,026
Cash flow hedging
Derivative assets:
Total derivative assets	0	1,925
Cash flow hedging | Prepaid and other current assets | Natural gas swaps
Derivative assets:
Total derivative assets	0	21
Cash flow hedging | Prepaid and other current assets | Interest rate caps
Derivative assets:
Total derivative assets	0	1,358
Cash flow hedging | Other long-term assets | Interest rate caps
Derivative assets:
Total derivative assets	0	546
Cash flow hedging | Accrued liabilities | Natural gas swaps
Derivative liabilities:
Total derivative liabilities	626	36
Cash flow hedging | Other long-term liabilities | Natural gas swaps
Derivative liabilities:
Total derivative liabilities	302	148
Cash flow hedging | Other long-term liabilities | Interest rate caps
Derivative liabilities:
Total derivative liabilities	3,202	1,842
Net investment hedging
Derivative assets:
Total derivative assets	40,125	18,843
Net investment hedging | Prepaid and other current assets | Cross-currency interest rate swaps
Derivative assets:
Total derivative assets	7,517	5,499
Net investment hedging | Other long-term assets | Cross-currency interest rate swaps
Derivative assets:
Total derivative assets	$ 32,608	$ 13,344

Financial Instruments - Effect

Financial Instruments - Effect on Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Amount of gain (loss) recognized in OCI on derivatives
Amount of gain (loss) recognized in OCI on derivatives	$ (401)	$ (393)	$ (4,215)	$ (3,878)
Amount of gain (loss) reclassified from AOCI into income
Amount of gain (loss) reclassified from AOCI into income	(448)	(101)	(636)	(265)
Interest rate caps
Amount of gain (loss) recognized in OCI on derivatives
Amount of gain (loss) recognized in OCI on derivatives	(216)	(93)	(3,264)	(3,396)
Interest rate caps | Interest expense
Amount of gain (loss) reclassified from AOCI into income
Amount of gain (loss) reclassified from AOCI into income	(157)	(71)	(449)	(164)
Natural gas swaps
Amount of gain (loss) recognized in OCI on derivatives
Amount of gain (loss) recognized in OCI on derivatives	(185)	(300)	(951)	(482)
Natural gas swaps | Cost of goods sold
Amount of gain (loss) reclassified from AOCI into income
Amount of gain (loss) reclassified from AOCI into income	$ (291)	$ (30)	$ (187)	$ (101)

Financial Instruments - Cash Fl

Financial Instruments - Cash Flow Hedge Impact on Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative
Cost of goods sold	$ (310,904)	$ (319,703)	$ (905,395)	$ (934,088)
Interest (expense) income	(27,697)	(28,238)	(84,855)	(84,622)
Gain (loss) on cash flow hedging relationships | Amount of gain (loss) reclassified from AOCI into income
Derivative
Cost of goods sold	(291)	(30)	(187)	(101)
Interest (expense) income	$ (157)	$ (71)	$ (449)	$ (164)

Financial Instruments - Net Inv

Financial Instruments - Net Investment Hedge Impact on AOCI (Details) - Cross-currency interest rate swaps - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative
Amount of gain (loss) recognized in OCI on derivative	$ 15,342	$ 1,138	$ 21,282	$ 8,799
Gain (loss) on sale of subsidiary
Derivative
Amount of gain (loss) reclassified from AOCI into income	0	0	0	0
Interest (expense) income
Derivative
Amount of gain (loss) recognized in income on derivative (amount excluded from effectiveness testing)	$ 2,395	$ 2,271	$ 6,888	$ 5,662

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate	38.40%	37.00%	39.30%	40.90%

Benefit Plans - Net Periodic Pe

Benefit Plans - Net Periodic Pension Expense Benefit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Pension Plans | U.S.
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Service cost	$ 251	$ 243	$ 751	$ 776
Interest cost	2,653	2,395	7,958	7,137
Expected return on plan assets	(2,912)	(3,165)	(8,733)	(9,515)
Amortization of net (gain) loss	0	0	0	0
Amortization of prior service cost (credit)	0	0	0	0
Curtailment gain recognized			0	(576)
Net periodic expense (benefit)	(8)	(527)	(24)	(2,178)
Defined Benefit Pension Plans | Foreign
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Service cost	780	933	2,464	2,665
Interest cost	801	(601)	2,458	2,512
Expected return on plan assets	(782)	453	(2,375)	(2,494)
Amortization of net (gain) loss	1	13	1	38
Amortization of prior service cost (credit)	6	0	18	0
Curtailment gain recognized			0	0
Net periodic expense (benefit)	806	798	2,566	2,721
Supplemental Retirement Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Interest cost	121	110	364	330
Net periodic expense (benefit)	121	110	364	330
Other Postretirement Benefits Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Service cost	3	3	10	12
Interest cost	38	43	114	108
Amortization of net (gain) loss	(9)	(11)	(27)	(33)
Amortization of prior service cost (credit)	(32)	(40)	(97)	(79)
Net periodic expense (benefit)	$ 0	$ (5)	$ 0	$ 8

Reportable Segments - Summary

Reportable Segments - Summary Financial Information by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting
Sales	$ 423,801	$ 427,203	$ 1,214,697	$ 1,228,113
Equity in net income from affiliated companies	17,261	5,605	31,625	31,123
Refining Services
Segment Reporting
Sales	117,522	122,536	338,874	333,698
Catalysts
Segment Reporting
Sales	25,565	16,347	62,226	50,113
Performance Materials
Segment Reporting
Sales	115,116	115,499	294,925	304,446
Performance Chemicals
Segment Reporting
Sales	165,598	172,821	518,672	539,856
Operating segments
Segment Reporting
Sales	427,030	429,818	1,225,138	1,239,427
Segment Adjusted EBITDA	145,377	128,397	399,240	382,223
Operating segments | Refining Services
Segment Reporting
Sales	118,335	123,369	341,469	336,154
Segment Adjusted EBITDA	51,166	49,559	133,721	126,368
Operating segments | Catalysts
Segment Reporting
Sales	25,612	16,347	62,335	50,167
Segment Adjusted EBITDA	31,638	15,751	79,372	62,227
Operating segments | Performance Materials
Segment Reporting
Sales	115,134	115,380	295,095	304,660
Segment Adjusted EBITDA	25,769	21,255	65,505	61,880
Operating segments | Performance Chemicals
Segment Reporting
Sales	167,949	174,722	526,239	548,446
Segment Adjusted EBITDA	36,804	41,832	120,642	131,748
Eliminations
Segment Reporting
Sales	(3,229)	(2,615)	(10,441)	(11,314)
Zeolyst Joint Venture | Catalysts
Segment Reporting
Sales	54,414	32,297	123,016	120,159
Segment Adjusted EBITDA	22,628	10,513	48,621	45,194
Equity in net income from affiliated companies	17,248	5,563	31,548	31,005
Amortization of investment in affiliate step-up	1,658	1,658	5,875	4,975
Joint venture depreciation, amortization and interest	$ 3,722	$ 3,292	$ 11,198	$ 9,214

Reportable Segments - Reconcil

Reportable Segments - Reconciliation of Net Income to Segment Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information
Net income attributable to PQ Group Holdings Inc.	$ 26,713	$ 14,185	$ 60,438	$ 30,181
Provision for income taxes	16,718	8,470	39,472	21,590
Interest expense, net	27,697	28,238	84,855	84,622
Depreciation and amortization	44,246	43,827	135,230	139,298
Segment EBITDA	115,374	94,720	319,995	275,691
Debt extinguishment costs	1,767	864	1,767	6,743
Net (gain) loss on asset disposals	1,136	5,202	(7,697)	11,106
Foreign currency exchange loss			5,380	15,347
Transaction and other related costs	2,930	215	3,938	827
Corporate, non-segment
Segment Reporting Information
Unallocated corporate expenses	7,693	10,276	28,062	27,322
Segment reconciling items
Segment Reporting Information
Joint venture depreciation, amortization and interest	3,722	3,292	11,198	9,214
Amortization of investment in affiliate step-up	1,658	1,658	5,875	4,975
Amortization of inventory step-up	0	0	0	1,603
Debt extinguishment costs	1,767	864	1,767	6,743
Net (gain) loss on asset disposals	1,136	5,202	(7,697)	11,106
Foreign currency exchange loss	4,457	3,527	5,380	15,347
LIFO expense	534	856	10,814	5,903
Transaction and other related costs	670	210	1,725	895
Equity-based compensation	4,806	4,252	13,576	11,879
Restructuring, integration and business optimization expenses	717	2,178	1,436	5,662
Defined benefit pension plan cost	834	112	2,379	260
Other	2,009	1,250	4,730	5,623
Operating segments
Segment Reporting Information
Segment Adjusted EBITDA	$ 145,377	$ 128,397	$ 399,240	$ 382,223

Stock-Based Compensation - Narr

Stock-Based Compensation - Narratives (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Stock-based compensation expense	$ 4,806	$ 4,252	$ 13,576	$ 11,879
Stock-based compensation expense, tax benefit	$ 1,187	$ 1,051	$ 3,353	$ 2,935
Number of shares available for grant (shares)	3,841,617		3,841,617
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Granted			1,245,628
Unrecognized stock-based compensation expense	$ 22,434		$ 22,434
Unrecognized stock-based compensation expense, period for recognition			1 year 8 months 19 days
Restricted Stock Units (RSUs) | Director
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period			1 year
Restricted Stock Units (RSUs) | Employee
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period			3 years
Performance Stock Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Granted			550,676
Award vesting period			3 years
Unrecognized stock-based compensation expense	$ 6,906		$ 6,906
Unrecognized stock-based compensation expense, period for recognition			2 years 4 months 28 days
Performance Stock Units (PSUs) | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting percentage			0.00%
Performance Stock Units (PSUs) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting percentage			200.00%

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of RSU and PSU Activity (Details)	9 Months Ended
	Sep. 30, 2019$ / sharesshares
Restricted Stock Units (RSUs)
Number of Units
Nonvested, beginning balance | shares	998,786
Granted | shares	1,245,628
Vested | shares	(148,551)
Forfeited | shares	20,837
Nonvested, ending balance | shares	2,075,026
Weighted Average Grant Date Fair Value (per share)
Weighted average grant date fair value, nonvested, beginning balance | $ / shares	$ 16.83
Weighted average grant date fair value, granted | $ / shares	15.42
Weighted average grant date fair value, vested | $ / shares	15.90
Weighted average grant date fair value, forfeited | $ / shares	16
Weighted average grant date fair value, nonvested, ending balance | $ / shares	$ 16.06
Performance Stock Units (PSUs)
Number of Units
Nonvested, beginning balance | shares	0
Granted | shares	550,676
Vested | shares	0
Forfeited | shares	0
Nonvested, ending balance | shares	550,676
Weighted Average Grant Date Fair Value (per share)
Weighted average grant date fair value, nonvested, beginning balance | $ / shares	$ 0
Weighted average grant date fair value, granted | $ / shares	15.41
Weighted average grant date fair value, vested | $ / shares	0
Weighted average grant date fair value, forfeited | $ / shares	0
Weighted average grant date fair value, nonvested, ending balance | $ / shares	$ 15.41

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Weighted average shares outstanding – Basic (shares)	134,511,819	133,336,352	134,213,571	133,237,653
Dilutive effect of unvested common shares and restricted stock units with service conditions, performance stock units considered probable of vesting and assumed stock option exercises and conversions (shares)	1,137,891	1,239,810	1,091,799	985,975
Weighted average shares outstanding – Diluted (shares)	135,649,710	134,576,162	135,305,370	134,223,628

Earnings per Share - Calculatio

Earnings per Share - Calculation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income attributable to PQ Group Holdings Inc.	$ 26,713	$ 14,185	$ 60,438	$ 30,181
Denominator:
Weighted average shares outstanding – Basic (shares)	134,511,819	133,336,352	134,213,571	133,237,653
Weighted average shares outstanding – Diluted (shares)	135,649,710	134,576,162	135,305,370	134,223,628
Net income per share:
Basic income per share (usd per share)	$ 0.20	$ 0.11	$ 0.45	$ 0.23
Diluted income per share (usd per share)	$ 0.20	$ 0.11	$ 0.45	$ 0.22

Earnings per Share - Anti-dilut

Earnings per Share - Anti-dilutive Shares (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restricted stock awards with performance only targets not yet achieved
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive (shares)	1,537,572	1,709,463	1,601,474	1,719,775
Stock options with performance only targets not yet achieved
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive (shares)	578,564	586,253	583,204	586,253
Anti-dilutive restricted stock awards, restricted stock units and performance stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive (shares)	0	0	0	18,076
Anti-dilutive stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive (shares)	863,063	760,766	863,063	668,596
Anti-dilutive stock options | $16.97 (usd per share)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive (shares)	621,747	621,747	621,747	621,747
Exercise price (usd per share)	$ 16.97	$ 16.97	$ 16.97	$ 16.97
Anti-dilutive stock options | $17.50 (usd per share)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive (shares)	241,316	139,019	241,316	46,849
Exercise price (usd per share)	$ 17.50	$ 17.50	$ 17.50	$ 17.50

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash paid during the period for:
Income taxes, net of refunds	$ 13,261	$ 16,121
Interest	82,349	83,612
Non-cash investing activity:
Capital expenditures acquired on account but unpaid as of the period end	13,265	10,624
Net interest proceeds on swaps designated as net investment hedges	$ 8,435	$ 4,279

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information - Cash and Restricted Cash Reconciliation (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 78,510	$ 57,854	$ 56,684
Restricted cash included in prepaid and other current assets	1,745		1,333
Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows	$ 80,255	$ 59,726	$ 58,017	$ 67,243
Restricted cash, balance sheet line item	us-gaap:PrepaidExpenseAndOtherAssetsCurrent

Subsequent Events (Details)

Subsequent Events (Details) - Oct. 31, 2019 - Subsequent Event [Member] - Cross-currency interest rate swaps € in Thousands, $ in Thousands	USD ($)	EUR (€)
Subsequent Event [Line Items]
Cash proceeds from cross-currency swap	$ 38,070
Euro
Subsequent Event [Line Items]
Derivative, notional amount | €		€ 280,000
U.S. Dollar
Subsequent Event [Line Items]
Derivative, notional amount	$ 311,379