Stepan (SCL) 10-Q 1 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 22, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	SCL
Entity Registrant Name	STEPAN CO
Entity Central Index Key	94,049
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		22,516,077

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net Sales		$ 507,997	$ 487,814		$ 1,527,198	$ 1,451,184
Cost of Sales	[1]	423,872	412,238		1,264,223	1,193,501
Gross Profit	[1]	84,125	75,576		262,975	257,683
Operating Expenses:
Selling	[1]	14,613	13,710		42,872	40,396
Administrative	[1]	21,904	18,480		59,441	54,141
Research, development and technical services	[1]	13,977	12,655		41,311	40,288
Deferred compensation expense		4,222	(129)		4,971	5,263
Total Operating expenses		54,716	44,716		148,595	140,088
Business restructuring expenses (Note 15)		(1,715)	(426)	[2]	(2,346)	(1,798)	[2]
Operating Income	[1]	27,694	30,434	[2]	112,034	115,797	[2]
Other Income (Expense):
Interest, net		(2,797)	(2,763)	[2]	(8,620)	(8,618)	[2]
Other, net (Note 14)	[1]	346	1,641	[2]	1,990	3,526	[2]
Nonoperating Income (Expense), Total		(2,451)	(1,122)		(6,630)	(5,092)
Income Before Provision for Income Taxes		25,243	29,312	[2]	105,404	110,705	[2]
Provision for Income Taxes (Note 17)		3,075	7,459		19,597	29,044
Net Income		22,168	21,853		85,807	81,661
Net Loss Attributable to Noncontrolling Interests (Note 2)			46		9	33
Net Income Attributable to Stepan Company		$ 22,168	$ 21,899		$ 85,816	$ 81,694
Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic		$ 0.96	$ 0.95		$ 3.73	$ 3.56
Diluted		$ 0.95	$ 0.94		$ 3.68	$ 3.50
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 9):
Basic		22,986	22,971		23,036	22,941
Diluted		23,288	23,374		23,324	23,361
Dividends Declared Per Common Share		$ 0.23	$ 0.21		$ 0.68	$ 0.62
[1]	The 2017 amounts for the noted line items have been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of Accounting Standards Update (ASU) No. 2017-7, Compensation –Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.
[2]	The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 22,168	$ 21,853	$ 85,807	$ 81,661
Other comprehensive income :
Foreign currency translation adjustments (Note 10)	(2,534)	9,837	(28,776)	26,288
Defined benefit pension adjustments, net of tax (Note 10)	788	539	2,293	1,671
Derivative instrument activity, net of tax (Note 10)	(2)	(2)	(7)	(7)
Total other comprehensive income	(1,748)	10,374	(26,490)	27,952
Comprehensive income (loss)	20,420	32,227	59,317	109,613
Comprehensive (income) loss attributable to noncontrolling interests (Note 2)	31	20	55	(26)
Comprehensive income (loss) attributable to Stepan Company	$ 20,451	$ 32,247	$ 59,372	$ 109,587

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 273,988	$ 298,894
Receivables, net	323,059	293,541
Inventories (Note 6)	195,169	172,748
Other current assets	22,816	23,553
Total current assets	815,032	788,736
Property, Plant and Equipment:
Cost	1,648,841	1,603,286
Less: Accumulated depreciation	(1,050,126)	(1,004,843)
Property, plant and equipment, net	598,715	598,443
Goodwill, net	22,480	25,118
Other intangible assets, net	14,988	18,538
Long-term investments (Note 3)	28,055	28,270
Other non-current assets	12,961	11,756
Total assets	1,492,231	1,470,861
Current Liabilities:
Current maturities of long-term debt (Note 13)	23,686	22,500
Accounts payable	209,302	204,977
Accrued liabilities	93,895	92,776
Total current liabilities	326,883	320,253
Deferred income taxes	18,798	10,962
Long-term debt, less current maturities (Notes 13)	262,551	268,299
Other non-current liabilities	105,585	130,433
Commitments and Contingencies (Note 7)
Equity:
Common stock, $1 par value; authorized 60,000,000 shares; 26,286,587 issued shares in 2018 and 26,070,787 issued shares in 2017	26,287	26,071
Additional paid-in capital	180,368	170,408
Accumulated other comprehensive loss (Note 10)	(126,007)	(99,563)
Retained earnings	792,134	721,741
Less: Common treasury stock, at cost, 3,773,946 shares in 2018 and 3,561,509 shares in 2017	(95,131)	(78,561)
Total Stepan Company stockholders’ equity	777,651	740,096
Noncontrolling interests (Note 2)	763	818
Total equity	778,414	740,914
Total liabilities and equity	$ 1,492,231	$ 1,470,861

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	26,286,587	26,070,787
Treasury stock, shares	3,773,946	3,561,509

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows From Operating Activities
Net income	$ 85,807	$ 81,661
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	60,778	57,121
Deferred compensation	4,971	5,263
Realized and unrealized gains on long-term investments	(1,241)	(3,677)
Stock-based compensation	6,722	6,248
Deferred income taxes	6,410	7,132
Other non-cash items	1,370	3,738
Changes in assets and liabilities:
Receivables, net	(34,807)	(37,713)
Inventories	(21,586)	14,789
Other current assets	727	(631)
Accounts payable and accrued liabilities	(6,906)	(5,872)
Pension liabilities	(5,059)	(2,141)
Environmental and legal liabilities	(763)	(392)
Deferred revenues	(243)	(843)
Net Cash Provided By Operating Activities	96,180	124,683
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(62,895)	(57,902)
Business acquisition (Note 16)	(21,475)	(4,339)
Other, net	1,684	(759)
Net Cash Used In Investing Activities	(82,686)	(63,000)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net	1,379	(7,309)
Other debt repayments	(5,714)	(5,714)
Dividends paid	(15,225)	(13,841)
Company stock repurchased	(13,500)	(4,500)
Stock option exercises	3,488	3,127
Other, net	(4,504)	(1,649)
Net Cash Used In Financing Activities	(34,076)	(29,886)
Effect of Exchange Rate Changes on Cash	(4,324)	6,560
Net Decrease in Cash and Cash Equivalents	(24,906)	38,357
Cash and Cash Equivalents at Beginning of Period	298,894	225,743
Cash and Cash Equivalents at End of Period	273,988	264,100
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds/payments	25,190	22,377
Cash payments of interest	$ 8,553	$ 9,113

Condensed Consolidated Financia

Condensed Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Condensed Consolidated Financial Statements	1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS The condensed consolidated financial statements included herein have been prepared by Stepan Company (the Company), without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) have been condensed or omitted pursuant to such rules and regulations, although management believes that the disclosures are adequate and make the information presented not misleading. In the opinion of management, all adjustments, consisting only of normal recurring accruals, necessary to present fairly the Company’s financial position as of September 30, 2018, results of operations for the three and nine months ended September 30, 2018 and 2017, and cash flows for the nine months ended September 30, 2018 and 2017, have been included. These financial statements and related footnotes should be read in conjunction with the financial statements and related footnotes included in the Company’s 2017 Annual Report on Form 10-K.

Reconciliations of Equity

Reconciliations of Equity	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Reconciliations of Equity	2. RECONCILIATIONS OF EQUITY Below are reconciliations of total equity, Company equity and equity attributable to noncontrolling interests for the nine months ended September 30, 2018 and 2017: (In thousands) Total Equity Stepan Company Equity Noncontrolling Interests’ Equity (3) Balance at January 1, 2018 $ 740,914 $ 740,096 $ 818 Net income 85,807 85,816 (9 ) Dividends (15,225 ) (15,225 ) — Common stock purchases (1) (16,756 ) (16,756 ) — Stock option exercises 3,488 3,488 — Defined benefit pension adjustments, net of tax 2,293 2,293 — Translation adjustments (28,776 ) (28,730 ) (46 ) Derivative instrument activity, net of tax (7 ) (7 ) — Other (2) 6,676 6,676 — Balance at September 30, 2018 $ 778,414 $ 777,651 $ 763 (In thousands) Total Equity Stepan Company Equity Noncontrolling Interests’ Equity (3) Balance at January 1, 2017 $ 635,916 $ 634,604 $ 1,312 Net income 81,661 81,694 (33 ) Dividends (13,841 ) (13,841 ) — Common stock purchases (1) (6,255 ) (6,255 ) — Stock option exercises 3,127 3,127 — Defined benefit pension adjustments, net of tax 1,671 1,671 — Translation adjustments 26,288 26,229 59 Derivative instrument activity, net of tax (7 ) (7 ) — Other (2) 7,711 7,711 — Balance at September 30, 2017 $ 736,271 $ 734,933 $ 1,338 (1) (2) Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (3)

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. FAIR VALUE MEASUREMENTS The following were the financial instruments held by the Company at September 30, 2018, and December 31, 2017, and the methods and assumptions used to estimate the instruments’ fair values: Cash and cash equivalents Carrying value approximated fair value because of the short maturity of the instruments. Derivative assets and liabilities Derivative assets and liabilities included the foreign currency exchange contracts discussed in Note 4. Fair value and carrying value were the same because the contracts were recorded at fair value. The fair values of the foreign currency contracts were calculated as the difference between the applicable forward foreign exchange rates at the reporting date and the contracted foreign exchange rates multiplied by the contracted notional amounts. See the table that follows the financial instrument descriptions for the reported fair values of derivative assets and liabilities. Long-term investments Long-term investments included the mutual fund assets the Company held to fund a portion of its deferred compensation liabilities and all of its non-qualified supplemental executive defined contribution obligations (see the defined contribution plans section of Note 8). Fair value and carrying value were the same because the mutual fund assets were recorded at fair value. Fair values for the mutual funds were calculated using the published market price per unit at the reporting date multiplied by the number of units held at the reporting date. See the table that follows the financial instrument descriptions for the reported fair value of long-term investments. Debt obligations The fair value of debt with original maturities greater than one year comprised the combined present values of scheduled principal and interest payments for each of the various loans, individually discounted at rates equivalent to those which could be obtained by the Company for new debt issues with durations equal to the average life to maturity of each loan. The fair values of the remaining Company debt obligations approximated their carrying values due to the short-term nature of the debt. The Company’s fair value measurements for debt fall within level 2 of the fair value hierarchy. At September 30, 2018, and December 31, 2017, the fair values and related carrying values of debt, including current maturities, were as follows (the fair value and carrying value amounts are presented without regard to unamortized debt issuance costs of $1,021,000 and $987,000 as of September 30, 2018 and December 31, 2017, respectively): (In thousands) September 30, 2018 December 31, 2017 Fair value $ 282,123 $ 293,272 Carrying value 287,258 291,786 The following tables present financial assets and liabilities measured on a recurring basis at fair value as of September 30, 2018, and December 31, 2017, and the level within the fair value hierarchy in which the fair value measurements fall: (In thousands) September 30, 2018 Level 1 Level 2 Level 3 Mutual fund assets $ 28,055 $ 28,055 $ — $ — Derivative assets: Foreign currency contracts 248 — 248 — Total assets at fair value $ 28,303 $ 28,055 $ 248 $ — Derivative liabilities: Foreign currency contracts $ 71 $ — $ 71 $ — (In thousands) December 31, 2017 Level 1 Level 2 Level 3 Mutual fund assets $ 28,270 $ 28,270 $ — $ — Derivative assets: Foreign currency contracts 335 — 335 — Total assets at fair value $ 28,605 $ 28,270 $ 335 $ — Derivative liabilities : Foreign currency contracts $ 94 $ — $ 94 $ —

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments	4. DERIVATIVE INSTRUMENTS The Company is exposed to certain risks relating to its ongoing business operations. The primary risk managed by the use of derivative instruments is foreign currency exchange risk. The Company holds forward foreign currency exchange contracts that are not designated as any type of accounting hedge as defined by GAAP. The Company uses these contracts to manage its exposure to exchange rate fluctuations on certain Company subsidiary cash, accounts receivable, accounts payable and other obligation balances that are denominated in currencies other than the entities’ functional currencies. The forward foreign exchange contracts are recognized on the balance sheet as either an asset or a liability measured at fair value. Gains and losses arising from recording the foreign exchange contracts at fair value are reported in earnings as offsets to the losses and gains reported in earnings arising from the re-measurement of the asset and liability balances into the applicable functional currencies. At September 30, 2018, and December 31, 2017, the Company had open forward foreign currency exchange contracts, all with durations of one to three months, to buy or sell foreign currencies with U.S. dollar equivalent amounts of $90,349,000 and $41,197,000, respectively. The fair values of the derivative instruments held by the Company on September 30, 2018, and December 31, 2017, are disclosed in Note 3. Derivative instrument gains and losses for the three- and nine- month periods ending September 30, 2018 and 2017 were immaterial. For amounts reclassified out of accumulated other comprehensive income (loss) (AOCI) into earnings for the three- and nine- month periods ended September 30, 2018 and 2017, see Note 10.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	5. STOCK-BASED COMPENSATION On September 30, 2018, the Company had stock options and stock awards outstanding under its 2006 Incentive Compensation Plan and stock options, stock awards and stock appreciation rights (SARs) outstanding under its 2011 Incentive Compensation Plan. SARs granted prior to 2015 are cash-settled, and SARs granted after 2014 are stock-settled. Stock options and SARs granted prior to 2017 generally cliff vested after two years. Starting in 2017, stock options and SARs have a three-year graded vesting feature, with one-third of the awards vesting each year. The Company has elected the straight-line method of expense attribution for the stock options and SARs with the graded vesting feature. Compensation expense recorded for all stock options, stock awards and SARs was as follows: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 $ 3,335 $ 1,697 $ 6,722 $ 6,248 The year-over-year and quarter-over-quarter increase in stock-based compensation expense was primarily attributable to cash-settled SARs. SARs compensation expense increased due to an increase in the fair values of cash-settled SARs that resulted from an increase in the market value of Company common stock in the third quarter of 2018 and first nine months of 2018 versus the same periods in 2017. Unrecognized compensation costs for stock options, stock awards and SARs were as follows: (In thousands) September 30, 2018 December 31, 2017 Stock options $ 1,917 $ 1,179 Stock awards 3,987 3,737 SARs 4,155 2,398 The increases in unrecognized compensation costs for stock options, stock awards and SARs reflected the 2018 grants of: Shares Stock options 77,038 Stock awards (at target) 49,426 SARs 171,131 The unrecognized compensation costs at September 30, 2018, are expected to be recognized over weighted-average periods of 2.0 years, 1.8 years and 2.0 years

Inventories

Inventories	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Inventories	6. INVENTORIES The composition of inventories at September 30, 2018, and December 31, 2017, was as follows: (In thousands) September 30, 2018 December 31, 2017 Finished goods $ 136,717 $ 117,529 Raw materials 58,452 55,219 Total inventories $ 195,169 $ 172,748 Inventories are priced primarily using the last-in, first-out inventory valuation method. If the first-in, first-out inventory valuation method had been used for all inventories, inventory balances would have been approximately $35,298,000 and $33,518,000 higher than reported at September 30, 2018, and December 31, 2017, respectively.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Contingencies	7. CONTINGENCIES There are a variety of legal proceedings pending or threatened against the Company. Some of these proceedings may result in fines, penalties, judgments or costs being assessed against the Company at some future time. The Company’s operations are subject to extensive local, state and federal regulations, including the U.S. Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) and the Superfund amendments of 1986 (Superfund) as well as similar regulations in other countries where the Company operates. Over the years, the Company has received requests for information related to or has been named by the government as a potentially responsible party (PRP) at a number of waste disposal sites where cleanup costs have been or may be incurred under CERCLA and similar state statutes. In addition, damages are being claimed against the Company in general liability actions for alleged personal injury or property damage in the case of some disposal and plant sites and in other commercial disputes. The Company believes that it has made adequate provisions for the costs it may incur with respect to these matters. As of September 30, 2018, the Company estimated a range of possible environmental and legal losses of $24.0 million to $45.5 million. At September 30, 2018, and December 31, 2017, the Company’s accrued liability for such losses, which represented the Company’s best estimate within the estimated range of possible environmental and legal losses, was $24.0 million and $24.2 million, respectively. Cash outlays related to legal and environmental matters approximated $1.0 million and $1.4 million for the nine-month periods ended September 30, 2018 and 2017, respectively. For certain sites, the Company has responded to information requests made by federal, state or local government agencies but has received no response confirming or denying the Company’s stated positions. As such, estimates of the total costs, or range of possible costs, of remediation, if any, or the Company’s share of such costs, if any, cannot be determined with respect to these sites. Consequently, the Company is unable to predict the effect thereof on the Company’s financial position, cash flows and results of operations. Given the information available, management believes the Company has no liability at these sites. Based upon the Company’s present knowledge with respect to its involvement at these sites, the possibility of other viable entities’ responsibilities for cleanup, and the extended period over which any costs would be incurred, the Company believes that these matters, individually and in the aggregate, will not have a material effect on the Company’s financial position. However, in the event of one or more adverse determinations with respect to such sites in any annual or interim period, the effect on the Company’s cash flows and results of operations for those periods could be material. Following are summaries of the material contingencies at September 30, 2018: Maywood, New Jersey Site The Company’s property in Maywood, New Jersey and property formerly owned by the Company adjacent to its current site and other nearby properties (Maywood site) were listed on the National Priorities List in September 1983 pursuant to the provisions of CERCLA because of certain alleged chemical contamination. Pursuant to an Administrative Order on Consent entered into between the U.S. Environmental Protection Agency (USEPA) and the Company for property formerly owned by the Company, and the issuance of an order by USEPA to the Company for property currently owned by the Company, the Company has completed various Remedial Investigation Feasibility Studies, and in September, 2014, the USEPA issued its Record of Decision (ROD) for chemically-contaminated soil. The USEPA has not yet issued a ROD for chemically-contaminated groundwater for the Maywood site. Based on the most current information available, the Company believes its recorded liability represents its best estimate of the cost of remediation for the Maywood site. The best estimate of the cost of remediation for the Maywood site could change as the Company continues to hold discussions with the USEPA, as the design of the remedial action progresses, if a groundwater ROD is issued or if other PRPs are identified. The ultimate amount for which the Company is liable could differ from the Company’s current recorded liability. In April 2015, the Company entered into an Administrative Settlement Agreement and Administrative Order on Consent with the USEPA which requires payment of certain costs and performance of certain investigative and design work for chemically-contaminated soil. Based on the Company’s review and analysis of this order, no changes to the Company’s recorded liability for claims associated with soil remediation of chemical contamination were required. In addition, under the terms of a settlement agreement reached on November 12, 2004, the U. S. Department of Justice and the Company agreed to fulfill the terms of a Cooperative Agreement reached in 1985 under which the United States will take title to and responsibility for radioactive waste removal at the Maywood site, including past and future remediation costs incurred by the United States. As such, the Company recorded no liability related to this settlement agreement. D’Imperio Property Site During the mid-1970’s, Jerome Lightman and the Lightman Drum Company disposed of hazardous substances at several sites in New Jersey. The Company was named as a PRP in a lawsuit in the U.S. District Court for the District of New Jersey that involved the D’Imperio Property Site located in New Jersey. In 2016, the PRPs were provided with updated remediation cost estimates which were considered in the Company’s determination of its range of estimated possible losses and liability balance. The changes in range of possible losses and liability balance were immaterial. Remediation work is continuing at this site. Based on current information, the Company believes that its recorded liability represents its best estimate of the cost of remediation for the D’Imperio site. Depending on the ultimate cost of the remediation at this site, the amount for which the Company is liable could differ from the current estimates. Wilmington Site The Company is currently contractually obligated to contribute to the response costs associated with the Company’s formerly-owned site in Wilmington, Massachusetts. Remediation at this site is being managed by its current owner, to whom the Company sold the property in 1980. Under the agreement, once total site remediation costs exceed certain levels, the Company is obligated to contribute up to five percent of future response costs associated with this site with no limitation on the ultimate amount of contributions. The Company has paid the current owner $2.6 million for the Company’s portion of environmental response costs through September 30, 2018. The Company has recorded a liability for its portion of the estimated remediation costs for the site. Depending on the ultimate cost of the remediation at this site, the amount for which the Company is liable could differ from the current estimates. The Company and other prior owners also entered into an agreement in April 2004 waiving certain statute of limitations defenses for claims which may be filed by the Town of Wilmington, Massachusetts, in connection with this site. While the Company has denied any liability for any such claims, the Company agreed to this waiver while the parties continue to discuss the resolution of any potential claim which may be filed. Other U.S. Sites Through the regular environmental monitoring of its plant production sites, the Company discovered levels of chemical contamination that were above thresholds allowed by law at two of its U.S. plants. The Company voluntarily reported its results to the applicable state environmental agencies. As a result, the Company is required to perform self-remediation of the affected areas. In the fourth quarter of 2016, the Company recognized a charge for the estimated cost of remediating the sites. Based on current information, the Company believes that its recorded liability for the remediation of the affected areas represents its best estimate of expected costs. However, actual costs could differ from current estimates.

Postretirement Benefit Plans

Postretirement Benefit Plans	9 Months Ended
	Sep. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Postretirement Benefit Plans	8. POSTRETIREMENT BENEFIT PLANS Defined Benefit Pension Plans The Company sponsors various funded qualified and unfunded non-qualified defined benefit pension plans, the most significant of which cover employees in the U.S. and U.K. locations. The U.S. and U.K. defined benefit pension plans are frozen and service benefits are no longer being accrued. Components of Net Periodic Benefit Cost UNITED STATES (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Interest cost $ 1,566 $ 1,665 $ 4,645 $ 4,988 Expected return on plan assets (2,320 ) (2,323 ) (6,962 ) (6,966 ) Amortization of net actuarial loss 987 738 2,860 2,314 Net periodic benefit cost $ 233 $ 80 $ 543 $ 336 UNITED KINGDOM (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Interest cost $ 138 $ 151 $ 430 $ 441 Expected return on plan assets (216 ) (203 ) (673 ) (593 ) Amortization of net actuarial loss 53 97 166 284 Net periodic benefit cost (income) $ (25 ) $ 45 $ (77 ) $ 132 In the first quarter of 2018, the Company implemented ASU No. 2017-07, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost Employer Contributions U.S. Plans The Company made a $5,000,000 voluntary contribution to its funded U.S. qualified defined benefit plans in the three- and nine-month periods ended September 30, 2018. No further contributions are expected to be made to the funded plans in 2018. As a result of pension funding relief provisions included in the Highway and Transportation Funding Act of 2014, the Company is not required to make contributions to the funded U.S. qualified defined benefit plans during 2018. Approximately $312,000 is expected to be contributed to the unfunded non-qualified plans in 2018. Of such amount, $256,000 had been contributed to the non-qualified plans as of September 30, 2018. U.K. Plan The Company’s U.K. subsidiary expects to contribute approximately $497,000 to its defined benefit pension plan in 2018. Of such amount, $372,000 had been contributed to the plan as of September 30, 2018. Defined Contribution Plans The Company sponsors retirement savings defined contribution plans that cover eligible U.S. and U.K. employees. The Company’s U.S. retirement plans include two qualified plans, one of which is a 401(k) plan and one of which is an employee stock ownership plan, and one non-qualified supplemental executive plan. Historically, the Company made profit sharing contributions into the qualified retirement plans for its U.S. employees. Profit sharing contributions were determined each year using a formula that was applied to Company earnings. The contributions, which were made partly in cash paid to the 401(k) plan and partly in Company common stock, are allocated to participant accounts on the basis of participant base earnings. Effective January 1, 2018, the Company amended its U.S. retirement saving plan and profit sharing formula, which resulted in a higher potential contribution percentage to the U.S. retirement savings plan and a lower potential profit sharing contribution percentage relative to prior years. Defined contribution plan expenses for the Company’s retirement savings plans and profit sharing were as follows: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Retirement savings plans $ 1,738 $ 1,275 $ 5,201 $ 3,758 Profit sharing plan 759 1,308 2,769 5,259 Total defined contribution expense $ 2,497 $ 2,583 $ 7,970 $ 9,017 The Company has a rabbi trust to fund the obligations of its non-qualified supplemental executive defined contribution plans (supplemental plans). The trust comprises various mutual fund investments selected by the participants of the supplemental plans. In accordance with the accounting guidance for rabbi trust arrangements, the assets of the trust and the obligations of the supplemental plans are reported on the Company’s consolidated balance sheets. The Company elected the fair value option for the mutual fund investment assets so that offsetting changes in the mutual fund values and defined contribution plan obligations would be recorded in earnings in the same period. Therefore, the mutual funds are reported at fair value with any subsequent changes in fair value recorded in the consolidated statements of income. The liabilities related to the supplemental plans increase (i.e., supplemental plan expense is recognized) when the value of the trust assets appreciates and decrease when the value of the trust assets declines (i.e., supplemental plan income is recognized). At September 30, 2018, the balance of the trust assets was $1,617,000, which equaled the balance of the supplemental plan liabilities (see the long-term investments section in Note 3 for further information regarding the Company’s mutual fund assets).

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	9. EARNINGS PER SHARE Below are the computations of basic and diluted earnings per share for the three and nine months ended September 30, 2018 and 2017: (In thousands, except per share amounts) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Computation of Basic Earnings per Share Net income attributable to Stepan Company $ 22,168 $ 21,899 $ 85,816 $ 81,694 Weighted-average number of common shares outstanding 22,986 22,971 23,036 22,941 Basic earnings per share $ 0.96 $ 0.95 $ 3.73 $ 3.56 Computation of Diluted Earnings per Share Net income attributable to Stepan Company $ 22,168 $ 21,899 $ 85,816 $ 81,694 Weighted-average number of shares outstanding 22,986 22,971 23,036 22,941 Add weighted-average net shares from assumed exercise of options (under treasury stock method) (1) 103 147 103 167 Add weighted-average net shares related to unvested stock awards (under treasury stock method) 3 8 2 8 Add weighted-average net shares from assumed exercise of SARs (under treasury stock method) (1) 113 140 111 142 Add weighted-average contingently issuable net shares related to performance stock awards (under treasury stock method) 83 108 72 103 Weighted-average shares applicable to diluted earnings 23,288 23,374 23,324 23,361 Diluted earnings per share $ 0.95 $ 0.94 $ 3.68 $ 3.50 (1)

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	10. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Below is the change in the Company’s AOCI balance by component (net of income taxes) for the three and nine months ended September 30, 2018 and 2017: (In thousands) Foreign Currency Translation Adjustments Defined Benefit Pension Plan Adjustments Cash Flow Hedge Adjustments Total Balance at June 30, 2017 $ (80,357 ) $ (29,658 ) $ 95 $ (109,920 ) Other comprehensive income before reclassifications 9,811 — — 9,811 Amounts reclassified from AOCI — 539 (2 ) 537 Net current-period other comprehensive income 9,811 539 (2 ) 10,348 Balance at June 30, 2017 $ (70,546 ) $ (29,119 ) $ 93 $ (99,572 ) Balance at June 30, 2018 $ (96,788 ) $ (27,588 ) $ 86 $ (124,290 ) Other comprehensive income before reclassifications (2,503 ) — — (2,503 ) Amounts reclassified from AOCI — 788 (2 ) 786 Net current-period other comprehensive income (2,503 ) 788 (2 ) (1,717 ) Balance at September 30, 2018 $ (99,291 ) $ (26,800 ) $ 84 $ (126,007 ) Balance at December 31, 2016 $ (96,775 ) $ (30,790 ) $ 100 $ (127,465 ) Other comprehensive income before reclassifications 26,229 — — 26,229 Amounts reclassified from AOCI — 1,671 (7 ) 1,664 Net current-period other comprehensive income 26,229 1,671 (7 ) 27,893 Balance at September 30, 2017 $ (70,546 ) $ (29,119 ) $ 93 $ (99,572 ) Balance at December 31, 2017 $ (70,561 ) $ (29,093 ) $ 91 $ (99,563 ) Other comprehensive income before reclassifications (28,730 ) — — (28,730 ) Amounts reclassified from AOCI — 2,293 (7 ) 2,286 Net current-period other comprehensive income (28,730 ) 2,293 (7 ) (26,444 ) Balance at September 30, 2018 $ (99,291 ) $ (26,800 ) $ 84 $ (126,007 ) Information regarding the reclassifications out of AOCI for the three and nine month periods ended September 30, 2018 and 2017, is displayed below: (In thousands) Amount Reclassified from AOCI (a) Affected Line Item in AOCI Components Three Months Ended September 30 Nine Months Ended September 30 Consolidated Statements of Income 2018 2017 2018 2017 Amortization of defined benefit pension actuarial losses $ (1,040 ) $ (835 ) $ (3,026 ) $ (2,598 ) (b) 252 296 733 927 Tax benefit $ (788 ) $ (539 ) $ (2,293 ) $ (1,671 ) Net of tax Gains and losses on cash flow hedges: Foreign exchange contracts 2 2 7 7 Cost of sales 2 2 7 7 Total before tax — — — — Tax benefit $ 2 $ 2 $ 7 $ 7 Net of tax Total reclassifications for the period $ (786 ) $ (537 ) $ (2,286 ) $ (1,664 ) Net of tax (a) Amounts in parentheses denote expense to statement of income. (b) This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 8 for additional details).

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segment Reporting	11. SEGMENT REPORTING The Company has three reportable segments: Surfactants, Polymers and Specialty Products. Net sales by segment for the three and nine months ended September 30, 2018 and 2017, were as follows: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Segment Net Sales Surfactants $ 346,884 $ 321,444 $ 1,062,708 $ 973,381 Polymers 141,646 147,754 404,446 415,551 Specialty Products 19,467 18,616 60,044 62,252 Total $ 507,997 $ 487,814 $ 1,527,198 $ 1,451,184 Segment operating income and reconciliations of segment operating income to consolidated income before income taxes for the three and nine months ended September 30, 2018 and 2017, are summarized below: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Segment Operating Income Surfactants $ 31,201 $ 22,559 $ 105,670 $ 92,080 Polymers 17,431 21,146 53,783 63,884 Specialty Products 2,653 990 6,543 7,711 Segment operating income 51,285 44,695 165,996 163,675 Business restructuring (1,715 ) (426 ) (2,346 ) (1,798 ) Unallocated corporate expenses (1) (21,876 ) (13,835 ) (51,616 ) (46,080 ) Consolidated operating income 27,694 30,434 112,034 115,797 Interest expense, net (2,797 ) (2,763 ) (8,620 ) (8,618 ) Other, net 346 1,641 1,990 3,526 Consolidated income before income taxes $ 25,243 $ 29,312 $ 105,404 $ 110,705 (1) Unallocated corporate expenses are primarily comprised of corporate administrative expenses (e.g., corporate finance, legal, human resources, information systems, deferred compensation and environmental remediation) that are not included in segment operating income and not used to evaluate segment performance. (2) The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	12. REVENUE FROM CONTRACTS WITH CUSTOMERS In the majority of instances the Company deems a contract with a customer to exist when a purchase order is received from a customer for a specified quantity of product or products and the Company acknowledges receipt of such purchase order. In some instances the Company has entered into manufacturing supply agreements with customers but these agreements typically do not bind a customer to any purchase volume requirements and thus an obligation is not created until the customer submits a purchase order to the Company. The Company’s contracts typically have a single performance obligation that is satisfied at the time product is shipped. For a small portion of the business, performance obligations are deemed satisfied when product is delivered to a customer location. Revenue is recognized when performance obligations under terms of a contract with a customer have been satisfied, which is predominantly at a point in time. With the 2018 adoption of ASU 2014-09, revenue is currently recognized when a customer obtains control of a product as compared to the “risk and rewards” criteria used in prior years. However, the adoption of ASU 2014-09 did not have a material impact on the Company’s financial position or results of operations during the first nine months of 2018. Payment terms on sales of product typically range from 30 to 60 days. As a result, the Company has concluded it does not provide any significant benefits of financing to its customers. The Company has elected to account for shipping and handling as activities to fulfill a promise to transfer the good. As such, shipping and handling fees billed to customers in a sales transaction are recorded in Net Sales and shipping and handling costs incurred are recorded in Cost of Sales. The Company has elected to exclude from Net Sales any value added, sales and other taxes that it collects concurrently with revenue producing activities. These accounting policy elections are consistent with the manner in which the Company has historically recorded shipping and handling fees and taxes. In some instances, a customer may qualify for a rebate based on the volume of purchases made over a specified period of time, typically a quarterly or annual period. The Company estimates the expected volume of total purchases using actual volumes, customer projections and historical order patterns and accrues for these rebates based on the best available information at the time. These estimated rebates are treated as a reduction to Net Sales with the offset being recognized within Current Liabilities. This methodology is consistent with the manner in which the Company has historically estimated and recorded volume based rebates. In other instances, discounts for early payments are offered to certain customers. These discounts are principally accrued for based on a customer’s historical use of discounts. These estimated early payment discounts are accounted for similarly to volume rebates. These forms of variable consideration are considered part of the transaction price. The Company warrants its products from defects. The Company has concluded that these represent assurance-type warranties as opposed to service-type warranties. Product defects are rare in occurrence. As a result, the Company does not maintain any warranty accruals until such time as it is probable a product defect exists. As of September 30, 2018, the Company did not have any contract assets or contract liabilities. A contract liability would typically arise when an advance or deposit is received from a customer before the Company recognizes revenue. In practice, this is extremely rare as it would require a customer to make a payment prior to a performance obligation being satisfied. If such a situation did arise the Company would maintain a deferred revenue liability until the time a performance obligation has been satisfied. The Company did not recognize any revenue in the current period from any pre-existing contract liability balance. The tables below provide a geographic disaggregation of net sales for the three and nine months ended September 30, 2018 and 2017. The Company’s business segmentation by geographic region most effectively captures the nature and economic characteristics of the Company’s revenue streams impacted by economic factors. This regional data is the predominant information used by senior management to assess the financial performance of operating segments and make resource allocation decisions. For the Three Months Ended September 30, 2018 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ 205,032 $ 87,720 $ 16,877 $ 309,629 Europe 68,120 45,780 2,590 116,490 Latin America 58,560 978 — 59,538 Asia 15,172 7,168 — 22,340 Total $ 346,884 $ 141,646 $ 19,467 $ 507,997 For the Three Months Ended September 30, 2017 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ 184,889 $ 86,002 $ 15,215 $ 286,106 Europe 69,325 53,008 3,401 125,734 Latin America 51,241 1,318 — 52,559 Asia 15,989 7,426 — 23,415 Total $ 321,444 $ 147,754 $ 18,616 $ 487,814 For the Nine Months Ended September 30, 2018 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ — Europe — Latin America — — Asia — — Total $ — $ — $ — $ — For the Nine Months Ended September 30, 2017 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ 582,148 $ 251,291 $ 46,353 $ 879,792 Europe 198,037 142,265 15,899 356,201 Latin America 143,305 3,576 — 146,881 Asia 49,891 18,419 — 68,310 Total $ 973,381 $ 415,551 $ 62,252 $ 1,451,184

Debt

Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt	13. DEBT At September 30, 2018, and December 31, 2017, debt comprised the following: (In thousands) Maturity Dates September 30, 2018 December 31, 2017 Unsecured private placement notes 3.95% (net of unamortized debt issuance cost of $371 and $346 for 2018 and 2017, respectively) 2021-2027 $ 99,630 $ 99,654 3.86% (net of unamortized debt issuance cost of $361 and $343 for 2018 and 2017, respectively) 2019-2025 99,639 99,657 4.86% (net of unamortized debt issuance cost of $195 and $191 for 2018 and 2017, respectively) 2018-2023 55,519 55,523 5.88% (net of unamortized debt issuance cost of $93 and $95 for 2018 and 2017, respectively) 2018-2022 22,764 28,476 5.69% (net of unamortized debt issuance cost of $1 and $12 for 2018 and 2017, respectively) 2018 5,713 5,703 Debt of foreign subsidiaries Unsecured bank debt, foreign currency 2018 2,972 1,786 Total debt $ 286,237 $ 290,799 Less current maturities 23,686 22,500 Long-term debt $ 262,551 $ 268,299 On January 30, 2018, the Company entered into a five year committed $350 million multi-currency revolving credit facility that matures on January 30, 2023 with a syndicate of banks. This credit facility replaced the Company’s prior $125 million credit agreement. The Company’s outstanding Note Purchase Agreements were amended effective January 30, 2018 to make certain covenants consistent with those included in the revolving credit agreement. The Company maintains standby letters of credit under its workers’ compensation insurance agreements and for other purposes, as needed from time to time, which are issued under the revolving credit agreement. As of September 30, 2018, the Company had outstanding letters of credit totaling $5,041,000 and no outstanding debt under the revolving credit agreement. There was $344,959,000 available under the revolving credit agreement as of September 30, 2018. The Company’s loan agreements contain provisions which, among others, require maintenance of certain financial ratios and place limitations on additional debt, investments and payment of dividends. Based on the loan agreement provisions that place limitations on dividend payments, unrestricted retained earnings (i.e., retained earnings available for dividend distribution) were $169,388,000 and $190,495,000 at September 30, 2018 and December 31, 2017, respectively.

Other, Net

Other, Net	9 Months Ended
	Sep. 30, 2018
Other Income And Expenses [Abstract]
Other, Net	14. OTHER, NET Other, net in the consolidated statements of income included the following: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Foreign exchange gains (losses) $ (274 ) $ 596 $ 895 $ 97 Investment income 91 69 320 220 Realized and unrealized gains on investments 737 1,101 1,241 3,677 Net periodic benefit cost (208 ) (125 ) (466 ) (468 ) Other, net $ 346 $ 1,641 $ 1,990 $ 3,526 Based on requirements of ASU No. 2017-07, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, .

Business Restructuring

Business Restructuring	9 Months Ended
	Sep. 30, 2018
Restructuring And Related Activities [Abstract]
Business Restructuring	15. BUSINESS RESTRUCTURING During the third quarter of 2018, the Company approved a plan to shut down Surfactants operations at its German plant site. As of September 30, the Company recognized restructuring costs of $1,410,000 comprised of asset and spare part write-downs. The shutdown decision was made in order to reduce the Company’s fixed cost base, facilitate a refocusing of Surfactant resources on higher margin end markets and allow for select assets to be repurposed to support future polyol growth. Decommissioning expenses associated with the shutdown will be incurred throughout 2019. In June 2017, the Company eliminated 11 positions from manufacturing operations at its Singapore plant, which is part of the Company’s Surfactant segment. The reduction in positions was made to better align the number of personnel with business requirements and to reduce costs at that site. As a result of the reduction in workforce, termination expense of $132,000 was recognized in the consolidated statements of income for the nine months ended September 30, 2017. There is no more termination liability remaining for this site. In May 2016, the Company announced plans to shut down its Longford Mills, Ontario, Canada (Longford Mills) manufacturing facility, a part of the Surfactant reportable segment, by December 31, 2016. The shutdown plan was developed as an effort to improve the Company’s asset utilization in North America and to reduce the Company’s fixed cost base. Manufacturing operations at the Longford Mills plant ceased by the end of 2016, and production of goods manufactured at the facility was transferred to other Company production sites in the United States. Decommissioning activities are expected to continue throughout the remainder of 2018 and 2019. As of September 30, 2018, $5,775,000 of aggregate restructuring expense has been recognized, reflecting $1,594,000 of termination benefits for approximately 30 employees and $4,181,000 for other expenses, principally asset decommissioning costs. Below is a reconciliation of the December 31, 2017 and the September 30, 2018 restructuring liabilities: (In thousands) Termination Benefits Other Expense Total Restructuring liability at December 31, 2017 $ 592 $ 99 $ 691 Expense recognized — 358 358 Amounts paid (140 ) (409 ) (549 ) Foreign currency translation (3 ) (4 ) (7 ) Restructuring liability at March 31, 2018 $ 449 $ 44 $ 493 Expense recognized — 273 273 Amounts paid (79 ) (226 ) (305 ) Foreign currency translation (7 ) (2 ) (9 ) Restructuring liability at June 30, 2018 $ 363 $ 89 $ 452 Expense recognized — 305 305 Amounts paid (61 ) (306 ) (367 ) Foreign currency translation 6 1 7 Restructuring liability at September 30, 2018 $ 308 $ 89 $ 397

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisition	16. ACQUISITION On March 26, 2018, the Company, through a subsidiary in Mexico, acquired BASF Mexicana, S.A.DE C.V.’s (BASF) production facility in Ecatepec, Mexico and a portion of its related surfactants business. The facility, which is near Mexico City, has over 50,000 metric tons of capacity, 124,000 square feet of warehouse space, a large laboratory and office space. The acquired assets and business are included in the Company’s Surfactants segment. The initial purchase price of the acquisition was $21,475,000 and was paid with cash on hand. The primary assets acquired were land, buildings, machinery and equipment and inventory. In the third quarter of 2018 the Company reached alignment with BASF on the final value of inventory acquired. The incremental inventory and related value-added taxes totaled $1,377,000 and increased the total assets acquired in the transaction from $21,475,000 to $22,852,000 as of September 30, 2018. The final inventory settlement payment is anticipated to be made in the fourth quarter of 2018. The purchase price allocation remains preliminary as of September 30, 2018. The acquisition was accounted for as a business combination, and, accordingly, the assets acquired were measured and recorded at their estimated fair values. The following table summarizes the assets acquired as a result of the acquisition: (In thousands) Assets: Property, plant and equipment $ 14,464 Inventory 5,687 Other Receivable 2,701 Total assets acquired $ 22,852 The acquired business is expected to have minimal impact on the Company’s 2018 financial results. Pro forma financial information for the first nine months of 2017 and 2018 has not been included because revenues and earnings of the Company would not have been significantly different than reported had the acquisition date been January 1, 2017.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	17. INCOME TAXES The Company’s effective tax rate was 12.2 percent for the third quarter of 2018 compared to 25.4 percent for the third quarter of 2017. The Company’s effective tax rate was 18.6 percent for the first nine months of 2018 compared to 26.2 percent for the first nine months of 2017. Both the third quarter and nine months decreases were primarily attributable to a lower U.S. statutory tax rate of 21 percent in 2018 versus 35 percent in 2017. This benefit was partially offset by: (a) certain unfavorable U.S. tax reform changes that became effective on January 1, 2018 (i.e. global intangible low taxed income, non-deductible executive compensation and the repeal of the domestic production activities deduction), and (b) lower excess tax benefits derived from stock based compensation awards exercised or distributed in 2018 versus 2017. In addition, during the third quarter of 2018, the Company filed applications to automatically change certain tax accounting methods related to the 2017 tax year. These method changes provided a favorable tax benefit that was partially offset by the negative tax impact recognized as a result of the Company’s plan to repatriate approximately $100 million of foreign cash in the fourth quarter of 2018. On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (Tax Act). The Tax Act made broad and complex changes to the U.S. tax code. Our accounting for the following elements of the Tax Act is complete: Deemed Repatriation Transition Tax: The Transition Tax is a tax on previously untaxed accumulated and current earnings and profits of our foreign subsidiaries. We were able to reasonably estimate the Transition Tax and recorded a provisional Transition Tax obligation of $19.4 million, with a corresponding adjustment of $19.4 million to income tax expense for the year ended December 31, 2017. On the basis of revised earnings and profits computations that were completed during the third quarter, we recognized a favorable measurement-period adjustment of $0.4 million to the Transition Tax obligation, with a corresponding favorable adjustment of $0.4 million to income tax expense during the third quarter of 2018. The effect of the measurement-period adjustment on the 2018 effective tax rate was a reduction of approximately 0.4 percent. The Transition Tax, which has now been determined to be complete, resulted in recording a total Transition Tax obligation of $19.0 million, with a corresponding adjustment of $19.0 million to income tax expense. Pursuant to the Tax Act, the Company’s foreign earnings have been subject to U.S. federal taxes. The Company now has the ability to repatriate to the U.S. parent the cash associated with these foreign earnings with little additional U.S. federal taxes. This cash may, however, be subject to foreign income and/or local country taxes if repatriated to the United States. In addition, repatriation of some foreign cash balances may be further restricted by local laws. During the quarter, the Company completed analyzing its foreign capital structure and determined the amount of cash at its foreign subsidiaries that can be repatriated to the United States with minimal additional taxes. In our analysis, the Company considered the future operating and liquidity needs of the Company and its foreign subsidiaries, while also considering the Company’s past assertion of indefinite reinvestment in its foreign earnings. The Company recorded $1.9 million of additional income tax expense during the third quarter of 2018. The effect of the adjustment on the 2018 effective tax rate was an increase of approximately 1.8 percent. With regard to the cash remaining at the Company’s foreign subsidiaries after the repatriation, the Company maintains its assertion of indefinite reinvestment in its foreign earnings. Reduction of U.S. federal corporate tax rate: The Tax Act reduced the corporate tax rate to 21 percent, effective January 1, 2018. We were able to reasonably estimate the impact to our deferred tax assets and liabilities and recorded a provisional net adjustment of $4.5 million for the year ended December 31, 2017. On the basis of revised temporary differences that were completed during the third quarter of 2018, we recognized a favorable measurement-period adjustment of $5.2 million. The effect of the measurement-period adjustment on the 2018 effective tax rate was a reduction of approximately 4.9 percent. The reduction of the U.S. federal corporate tax rate, which has now been determined to be complete, resulted in recording a total deferred income tax benefit of $9.7 million as a result of revaluing the Company’s deferred tax assets and liabilities. Cost recovery: The Company is able to claim bonus depreciation to accelerate the expensing of the cost of certain qualified property acquired and placed in service after September 27, 2017 and before January 1, 2024. For the first five-year period (through 2022), the Company can deduct 100 percent of the cost of qualified property. Starting in 2023, the additional bonus depreciation is gradually phased out by 20 percent each year through 2027. We have completed the computations necessary and completed an inventory of our 2017 expenditures for property that was placed into service after September 27, 2017 through December 31, 2017 and that qualifies for immediate expensing. We concluded the impact of the true-up adjustment from this analysis, which has now been determined to be complete, was immaterial . Valuation allowances: The Company must assess whether valuation allowances assessments are affected by various aspects of the Tax Act (e.g., GILTI inclusions and new categories of foreign tax credits). The Tax Act did not result in any additional valuation allowances for the Company. Our accounting for the following elements of the Tax Act is incomplete. As noted at year-end, we were not yet able to reasonably estimate the effects for the items set forth below. Therefore, no provisional adjustments were recorded. The Company expects to finalize its computations for these items in the fourth quarter of 2018. Global intangible low taxed income (GILTI): The Tax Act requires the Company to include certain income (GILTI) of its foreign subsidiaries in gross income. The amount of this inclusion is determined under complex rules, and depends, in part, on the character of income earned by the foreign subsidiaries, the tax bases of those subsidiaries’ assets and the amount of certain interest expenses. Under GAAP, we are allowed to make an accounting policy choice of either (1) treating taxes due on future income inclusions related to GILTI as a current-period expense when incurred (the period cost method) or (2) accounting for such amounts in measuring deferred taxes (the deferred method). Our selection of an accounting policy with respect to the new GILTI tax rules will depend, in part, on analyzing our global income to determine whether we expect to have future income inclusions related to GILTI and, if so, what the impact is expected to be. These determinations depend not only on our current structure and estimated future results of global operations but also our intent and ability to modify our structure and/or our business. Therefore, we have not made any adjustments or estimates related to any potential deferred tax liabilities related to GILTI in our financial statements and have not made a policy decision regarding whether to record deferred tax liabilities related to GILTI. Deductibility of Executive Compensation: The Tax Act amended certain aspects of Section 162(m) of the Internal Revenue Code (Section 162(m)), which generally disallows a tax deduction for annual compensation paid to “covered employees” in excess of $1 million, including eliminating an exception to the deduction limit for “qualified performance-based compensation,” effective for tax years beginning after December 31, 2017. The Tax Act provides for a grandfather provision, pursuant to which remuneration that is provided pursuant to a written binding contract in effect on November 2, 2017, and which has not been modified in any material respect on or after that date, will not be subject to the amendments made to Section 162(m) by the Tax Act and will remain eligible for deduction as qualified performance-based compensation. For compensation not yet paid or incurred related to services performed before January 1, 2018, to the extent available, we intend to continue to treat as “qualified performance-based compensation” that is grandfathered under the Tax Act which is deductible compensation. However, we have not yet completed our evaluation of our existing compensation arrangements to determine whether any amounts payable to our Section 162(m) covered employees may continue to constitute qualified performance-based compensation under Section 162(m) and qualify under the grandfather provision.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	18. RECENT ACCOUNTING PRONOUNCEMENTS In May 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-9, Revenue from Contracts with Customers (Topic 606) Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date Revenue from Contracts with Customers In February 2016, the FASB issued ASU No. 2016-2, Leases (Topic 842) Leases (Topic 842): Targeted Improvements, Leases (Topic 842) In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory In January 2017, the FASB issued ASU No. 2017-4, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued ASU No. 2017-1, Business Combination (Topic 805): Clarifying the Definition of a Business, In March 2017, the FASB issued ASU No. 2017-7, Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities In January 2018, the FASB issued ASU No. 2018-01, Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842 In February 2018, the FASB issued ASU No. 2018-02, Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. In August 2018, the FASB issued ASU No. 2018-14, Compensation-Retirement Benefits-Defined Benefit Plans-General (Subtopic 715-20). In August 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use software (Subtopic 350-40) Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-9, Revenue from Contracts with Customers (Topic 606) Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date Revenue from Contracts with Customers In February 2016, the FASB issued ASU No. 2016-2, Leases (Topic 842) Leases (Topic 842): Targeted Improvements, Leases (Topic 842) In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory In January 2017, the FASB issued ASU No. 2017-4, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment In January 2017, the FASB issued ASU No. 2017-1, Business Combination (Topic 805): Clarifying the Definition of a Business, In March 2017, the FASB issued ASU No. 2017-7, Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities In January 2018, the FASB issued ASU No. 2018-01, Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842 In February 2018, the FASB issued ASU No. 2018-02, Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820) Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. In August 2018, the FASB issued ASU No. 2018-14, Compensation-Retirement Benefits-Defined Benefit Plans-General (Subtopic 715-20). In August 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use software (Subtopic 350-40) Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract

Reconciliations of Equity (Tabl

Reconciliations of Equity (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Reconciliations of Total Equity	Below are reconciliations of total equity, Company equity and equity attributable to noncontrolling interests for the nine months ended September 30, 2018 and 2017: (In thousands) Total Equity Stepan Company Equity Noncontrolling Interests’ Equity (3) Balance at January 1, 2018 $ 740,914 $ 740,096 $ 818 Net income 85,807 85,816 (9 ) Dividends (15,225 ) (15,225 ) — Common stock purchases (1) (16,756 ) (16,756 ) — Stock option exercises 3,488 3,488 — Defined benefit pension adjustments, net of tax 2,293 2,293 — Translation adjustments (28,776 ) (28,730 ) (46 ) Derivative instrument activity, net of tax (7 ) (7 ) — Other (2) 6,676 6,676 — Balance at September 30, 2018 $ 778,414 $ 777,651 $ 763 (In thousands) Total Equity Stepan Company Equity Noncontrolling Interests’ Equity (3) Balance at January 1, 2017 $ 635,916 $ 634,604 $ 1,312 Net income 81,661 81,694 (33 ) Dividends (13,841 ) (13,841 ) — Common stock purchases (1) (6,255 ) (6,255 ) — Stock option exercises 3,127 3,127 — Defined benefit pension adjustments, net of tax 1,671 1,671 — Translation adjustments 26,288 26,229 59 Derivative instrument activity, net of tax (7 ) (7 ) — Other (2) 7,711 7,711 — Balance at September 30, 2017 $ 736,271 $ 734,933 $ 1,338 (1) (2) Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (3)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Values and Related Carrying Values of Debt	At September 30, 2018, and December 31, 2017, the fair values and related carrying values of debt, including current maturities, were as follows (the fair value and carrying value amounts are presented without regard to unamortized debt issuance costs of $1,021,000 and $987,000 as of September 30, 2018 and December 31, 2017, respectively): (In thousands) September 30, 2018 December 31, 2017 Fair value $ 282,123 $ 293,272 Carrying value 287,258 291,786
Financial Assets and Liabilities Measured on a Recurring Basis at Fair Value	The following tables present financial assets and liabilities measured on a recurring basis at fair value as of September 30, 2018, and December 31, 2017, and the level within the fair value hierarchy in which the fair value measurements fall: (In thousands) September 30, 2018 Level 1 Level 2 Level 3 Mutual fund assets $ 28,055 $ 28,055 $ — $ — Derivative assets: Foreign currency contracts 248 — 248 — Total assets at fair value $ 28,303 $ 28,055 $ 248 $ — Derivative liabilities: Foreign currency contracts $ 71 $ — $ 71 $ — (In thousands) December 31, 2017 Level 1 Level 2 Level 3 Mutual fund assets $ 28,270 $ 28,270 $ — $ — Derivative assets: Foreign currency contracts 335 — 335 — Total assets at fair value $ 28,605 $ 28,270 $ 335 $ — Derivative liabilities : Foreign currency contracts $ 94 $ — $ 94 $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Compensation Expense Recorded for All Stock Options, Stock Awards and SARs	Compensation expense recorded for all stock options, stock awards and SARs was as follows: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 $ 3,335 $ 1,697 $ 6,722 $ 6,248
Unrecognized Compensation Costs for Stock Options, Stock Awards and SARs	Unrecognized compensation costs for stock options, stock awards and SARs were as follows: (In thousands) September 30, 2018 December 31, 2017 Stock options $ 1,917 $ 1,179 Stock awards 3,987 3,737 SARs 4,155 2,398
Share Based Payment Awards Granted in Period	The increases in unrecognized compensation costs for stock options, stock awards and SARs reflected the 2018 grants of: Shares Stock options 77,038 Stock awards (at target) 49,426 SARs 171,131

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Composition of Inventories	The composition of inventories at September 30, 2018, and December 31, 2017, was as follows: (In thousands) September 30, 2018 December 31, 2017 Finished goods $ 136,717 $ 117,529 Raw materials 58,452 55,219 Total inventories $ 195,169 $ 172,748

Postretirement Benefit Plans (T

Postretirement Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Components of Net Periodic Benefit Cost	Components of Net Periodic Benefit Cost UNITED STATES (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Interest cost $ 1,566 $ 1,665 $ 4,645 $ 4,988 Expected return on plan assets (2,320 ) (2,323 ) (6,962 ) (6,966 ) Amortization of net actuarial loss 987 738 2,860 2,314 Net periodic benefit cost $ 233 $ 80 $ 543 $ 336 UNITED KINGDOM (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Interest cost $ 138 $ 151 $ 430 $ 441 Expected return on plan assets (216 ) (203 ) (673 ) (593 ) Amortization of net actuarial loss 53 97 166 284 Net periodic benefit cost (income) $ (25 ) $ 45 $ (77 ) $ 132
Defined Contribution Plan Expenses for Company's Retirement Savings Plans and Profit Sharing	Defined contribution plan expenses for the Company’s retirement savings plans and profit sharing were as follows: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Retirement savings plans $ 1,738 $ 1,275 $ 5,201 $ 3,758 Profit sharing plan 759 1,308 2,769 5,259 Total defined contribution expense $ 2,497 $ 2,583 $ 7,970 $ 9,017

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	Below are the computations of basic and diluted earnings per share for the three and nine months ended September 30, 2018 and 2017: (In thousands, except per share amounts) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Computation of Basic Earnings per Share Net income attributable to Stepan Company $ 22,168 $ 21,899 $ 85,816 $ 81,694 Weighted-average number of common shares outstanding 22,986 22,971 23,036 22,941 Basic earnings per share $ 0.96 $ 0.95 $ 3.73 $ 3.56 Computation of Diluted Earnings per Share Net income attributable to Stepan Company $ 22,168 $ 21,899 $ 85,816 $ 81,694 Weighted-average number of shares outstanding 22,986 22,971 23,036 22,941 Add weighted-average net shares from assumed exercise of options (under treasury stock method) (1) 103 147 103 167 Add weighted-average net shares related to unvested stock awards (under treasury stock method) 3 8 2 8 Add weighted-average net shares from assumed exercise of SARs (under treasury stock method) (1) 113 140 111 142 Add weighted-average contingently issuable net shares related to performance stock awards (under treasury stock method) 83 108 72 103 Weighted-average shares applicable to diluted earnings 23,288 23,374 23,324 23,361 Diluted earnings per share $ 0.95 $ 0.94 $ 3.68 $ 3.50 (1)

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Summary of Changes in Accumulated Other Comprehensive Income	Below is the change in the Company’s AOCI balance by component (net of income taxes) for the three and nine months ended September 30, 2018 and 2017: (In thousands) Foreign Currency Translation Adjustments Defined Benefit Pension Plan Adjustments Cash Flow Hedge Adjustments Total Balance at June 30, 2017 $ (80,357 ) $ (29,658 ) $ 95 $ (109,920 ) Other comprehensive income before reclassifications 9,811 — — 9,811 Amounts reclassified from AOCI — 539 (2 ) 537 Net current-period other comprehensive income 9,811 539 (2 ) 10,348 Balance at June 30, 2017 $ (70,546 ) $ (29,119 ) $ 93 $ (99,572 ) Balance at June 30, 2018 $ (96,788 ) $ (27,588 ) $ 86 $ (124,290 ) Other comprehensive income before reclassifications (2,503 ) — — (2,503 ) Amounts reclassified from AOCI — 788 (2 ) 786 Net current-period other comprehensive income (2,503 ) 788 (2 ) (1,717 ) Balance at September 30, 2018 $ (99,291 ) $ (26,800 ) $ 84 $ (126,007 ) Balance at December 31, 2016 $ (96,775 ) $ (30,790 ) $ 100 $ (127,465 ) Other comprehensive income before reclassifications 26,229 — — 26,229 Amounts reclassified from AOCI — 1,671 (7 ) 1,664 Net current-period other comprehensive income 26,229 1,671 (7 ) 27,893 Balance at September 30, 2017 $ (70,546 ) $ (29,119 ) $ 93 $ (99,572 ) Balance at December 31, 2017 $ (70,561 ) $ (29,093 ) $ 91 $ (99,563 ) Other comprehensive income before reclassifications (28,730 ) — — (28,730 ) Amounts reclassified from AOCI — 2,293 (7 ) 2,286 Net current-period other comprehensive income (28,730 ) 2,293 (7 ) (26,444 ) Balance at September 30, 2018 $ (99,291 ) $ (26,800 ) $ 84 $ (126,007 )
Summary of Amounts Reclassifications Out of Accumulated Other Comprehensive Income	Information regarding the reclassifications out of AOCI for the three and nine month periods ended September 30, 2018 and 2017, is displayed below: (In thousands) Amount Reclassified from AOCI (a) Affected Line Item in AOCI Components Three Months Ended September 30 Nine Months Ended September 30 Consolidated Statements of Income 2018 2017 2018 2017 Amortization of defined benefit pension actuarial losses $ (1,040 ) $ (835 ) $ (3,026 ) $ (2,598 ) (b) 252 296 733 927 Tax benefit $ (788 ) $ (539 ) $ (2,293 ) $ (1,671 ) Net of tax Gains and losses on cash flow hedges: Foreign exchange contracts 2 2 7 7 Cost of sales 2 2 7 7 Total before tax — — — — Tax benefit $ 2 $ 2 $ 7 $ 7 Net of tax Total reclassifications for the period $ (786 ) $ (537 ) $ (2,286 ) $ (1,664 ) Net of tax (a) Amounts in parentheses denote expense to statement of income. (b) This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 8 for additional details).

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Operating Segment	The Company has three reportable segments: Surfactants, Polymers and Specialty Products. Net sales by segment for the three and nine months ended September 30, 2018 and 2017, were as follows: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Segment Net Sales Surfactants $ 346,884 $ 321,444 $ 1,062,708 $ 973,381 Polymers 141,646 147,754 404,446 415,551 Specialty Products 19,467 18,616 60,044 62,252 Total $ 507,997 $ 487,814 $ 1,527,198 $ 1,451,184
Reconciliation of Segment Information to Consolidated Financial Statements	Segment operating income and reconciliations of segment operating income to consolidated income before income taxes for the three and nine months ended September 30, 2018 and 2017, are summarized below: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Segment Operating Income Surfactants $ 31,201 $ 22,559 $ 105,670 $ 92,080 Polymers 17,431 21,146 53,783 63,884 Specialty Products 2,653 990 6,543 7,711 Segment operating income 51,285 44,695 165,996 163,675 Business restructuring (1,715 ) (426 ) (2,346 ) (1,798 ) Unallocated corporate expenses (1) (21,876 ) (13,835 ) (51,616 ) (46,080 ) Consolidated operating income 27,694 30,434 112,034 115,797 Interest expense, net (2,797 ) (2,763 ) (8,620 ) (8,618 ) Other, net 346 1,641 1,990 3,526 Consolidated income before income taxes $ 25,243 $ 29,312 $ 105,404 $ 110,705 (1) Unallocated corporate expenses are primarily comprised of corporate administrative expenses (e.g., corporate finance, legal, human resources, information systems, deferred compensation and environmental remediation) that are not included in segment operating income and not used to evaluate segment performance. (2) The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue From Contract With Customer [Abstract]
Geographic Disaggregation of Net Sales	The tables below provide a geographic disaggregation of net sales for the three and nine months ended September 30, 2018 and 2017. The Company’s business segmentation by geographic region most effectively captures the nature and economic characteristics of the Company’s revenue streams impacted by economic factors. This regional data is the predominant information used by senior management to assess the financial performance of operating segments and make resource allocation decisions. For the Three Months Ended September 30, 2018 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ 205,032 $ 87,720 $ 16,877 $ 309,629 Europe 68,120 45,780 2,590 116,490 Latin America 58,560 978 — 59,538 Asia 15,172 7,168 — 22,340 Total $ 346,884 $ 141,646 $ 19,467 $ 507,997 For the Three Months Ended September 30, 2017 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ 184,889 $ 86,002 $ 15,215 $ 286,106 Europe 69,325 53,008 3,401 125,734 Latin America 51,241 1,318 — 52,559 Asia 15,989 7,426 — 23,415 Total $ 321,444 $ 147,754 $ 18,616 $ 487,814 For the Nine Months Ended September 30, 2018 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ — Europe — Latin America — — Asia — — Total $ — $ — $ — $ — For the Nine Months Ended September 30, 2017 (In thousands) Surfactants Polymers Specialty Products Total Geographic Market North America $ 582,148 $ 251,291 $ 46,353 $ 879,792 Europe 198,037 142,265 15,899 356,201 Latin America 143,305 3,576 — 146,881 Asia 49,891 18,419 — 68,310 Total $ 973,381 $ 415,551 $ 62,252 $ 1,451,184

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt	At September 30, 2018, and December 31, 2017, debt comprised the following: (In thousands) Maturity Dates September 30, 2018 December 31, 2017 Unsecured private placement notes 3.95% (net of unamortized debt issuance cost of $371 and $346 for 2018 and 2017, respectively) 2021-2027 $ 99,630 $ 99,654 3.86% (net of unamortized debt issuance cost of $361 and $343 for 2018 and 2017, respectively) 2019-2025 99,639 99,657 4.86% (net of unamortized debt issuance cost of $195 and $191 for 2018 and 2017, respectively) 2018-2023 55,519 55,523 5.88% (net of unamortized debt issuance cost of $93 and $95 for 2018 and 2017, respectively) 2018-2022 22,764 28,476 5.69% (net of unamortized debt issuance cost of $1 and $12 for 2018 and 2017, respectively) 2018 5,713 5,703 Debt of foreign subsidiaries Unsecured bank debt, foreign currency 2018 2,972 1,786 Total debt $ 286,237 $ 290,799 Less current maturities 23,686 22,500 Long-term debt $ 262,551 $ 268,299

Other, Net (Tables)

Other, Net (Tables)	9 Months Ended
	Sep. 30, 2018
Other Income And Expenses [Abstract]
Other Net in Consolidated Statements of Income	Other, net in the consolidated statements of income included the following: (In thousands) Three Months Ended September 30 Nine Months Ended September 30 2018 2017 2018 2017 Foreign exchange gains (losses) $ (274 ) $ 596 $ 895 $ 97 Investment income 91 69 320 220 Realized and unrealized gains on investments 737 1,101 1,241 3,677 Net periodic benefit cost (208 ) (125 ) (466 ) (468 ) Other, net $ 346 $ 1,641 $ 1,990 $ 3,526

Business Restructuring (Tables)

Business Restructuring (Tables)	9 Months Ended
	Sep. 30, 2018
Restructuring And Related Activities [Abstract]
Reconciliation of Restructuring Liabilities	Below is a reconciliation of the December 31, 2017 and the September 30, 2018 restructuring liabilities: (In thousands) Termination Benefits Other Expense Total Restructuring liability at December 31, 2017 $ 592 $ 99 $ 691 Expense recognized — 358 358 Amounts paid (140 ) (409 ) (549 ) Foreign currency translation (3 ) (4 ) (7 ) Restructuring liability at March 31, 2018 $ 449 $ 44 $ 493 Expense recognized — 273 273 Amounts paid (79 ) (226 ) (305 ) Foreign currency translation (7 ) (2 ) (9 ) Restructuring liability at June 30, 2018 $ 363 $ 89 $ 452 Expense recognized — 305 305 Amounts paid (61 ) (306 ) (367 ) Foreign currency translation 6 1 7 Restructuring liability at September 30, 2018 $ 308 $ 89 $ 397

Acquisition (Tables)

Acquisition (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Summary of Assets Acquired Measured and Recorded at Estimated Fair Values	The following table summarizes the assets acquired as a result of the acquisition: (In thousands) Assets: Property, plant and equipment $ 14,464 Inventory 5,687 Other Receivable 2,701 Total assets acquired $ 22,852

Reconciliations of Equity - Rec

Reconciliations of Equity - Reconciliations of Total Equity (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reconciliations of total equity
Beginning Balance				$ 740,914	$ 635,916
Net income		$ 22,168	$ 21,853	85,807	81,661
Dividends				(15,225)	(13,841)
Common stock purchases	[1]			(16,756)	(6,255)
Stock option exercises				3,488	3,127
Defined benefit pension adjustments, net of tax		788	539	2,293	1,671
Translation adjustments		(2,534)	9,837	(28,776)	26,288
Derivative instrument activity, net of tax		(2)	(2)	(7)	(7)
Other	[2]			6,676	7,711
Ending Balance		778,414	736,271	778,414	736,271
Stepan Company Equity [Member]
Reconciliations of total equity
Beginning Balance				740,096	634,604
Net income				85,816	81,694
Dividends				(15,225)	(13,841)
Common stock purchases	[1]			(16,756)	(6,255)
Stock option exercises				3,488	3,127
Defined benefit pension adjustments, net of tax				2,293	1,671
Translation adjustments				(28,730)	26,229
Derivative instrument activity, net of tax				(7)	(7)
Other	[2]			6,676	7,711
Ending Balance		777,651	734,933	777,651	734,933
Noncontrolling Interests' Equity [Member]
Reconciliations of total equity
Beginning Balance	[3]			818	1,312
Net income	[3]			(9)	(33)
Translation adjustments	[3]			(46)	59
Ending Balance	[3]	$ 763	$ 1,338	$ 763	$ 1,338
[1]	Includes the value of Company common stock purchased in the open market and from the Company’s retirement plans and the value of Company common stock tendered by employees to settle statutory withholding taxes related to distributions of deferred performance awards and deferred management incentive compensation and exercises of stock appreciation rights.
[2]	Primarily comprised of activity related to stock-based compensation and deferred compensation. Beginning in 2018, also includes beginning retained earnings adjustment as a result of the Company’s first quarter 2018 adoption of ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory.
[3]	Reflects the noncontrolling interest in the Company’s China joint venture.

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Unamortized debt issuance cost	$ 1,021,000	$ 987,000

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values and Related Carrying Values of Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying value	$ 287,258	$ 291,786
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value	$ 282,123	$ 293,272

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured on a Recurring Basis at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Mutual fund assets	$ 28,055	$ 28,270
Derivative assets:
Foreign currency contracts	248	335
Total assets at fair value	28,303	28,605
Derivative liabilities:
Foreign currency contracts	71	94
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Mutual fund assets	28,055	28,270
Derivative assets:
Total assets at fair value	28,055	28,270
Level 2 [Member]
Derivative assets:
Foreign currency contracts	248	335
Total assets at fair value	248	335
Derivative liabilities:
Foreign currency contracts	$ 71	$ 94

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$ 90,349,000	$ 41,197,000
Minimum [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative foreign currency exchange contracts durations	1 month
Maximum [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative foreign currency exchange contracts durations	3 months

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018
Stock Option and Stock Appreciation Rights (SARs) Granted Prior to 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
Stock Option and Stock Appreciation Rights (SARS) Granted in 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	3 years
Percentage of awards vesting in each year	33.33%
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average period for amortization of unrecognized compensation cost	2 years
Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average period for amortization of unrecognized compensation cost	1 year 9 months 18 days
SARs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average period for amortization of unrecognized compensation cost	2 years

Stock-Based Compensation - Comp

Stock-Based Compensation - Compensation Expense Recorded for All Stock Options, Stock Awards and SARs (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Compensation expense	$ 3,335	$ 1,697	$ 6,722	$ 6,248

Stock-Based Compensation - Unre

Stock-Based Compensation - Unrecognized Compensation Costs for Stock Options, Stock Awards and SARs (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs for stock options, stock awards and SARs	$ 1,917	$ 1,179
Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs for stock options, stock awards and SARs	3,987	3,737
SARs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs for stock options, stock awards and SARs	$ 4,155	$ 2,398

Stock-Based Compensation - Shar

Stock-Based Compensation - Share Based Payment Awards Granted in Period (Detail)	9 Months Ended
	Sep. 30, 2018shares
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted in period	77,038
Stock Awards (at target) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted in period	49,426
SARs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted in period	171,131

Inventories - Composition of In

Inventories - Composition of Inventories (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Finished goods	$ 136,717	$ 117,529
Raw materials	58,452	55,219
Total inventories	$ 195,169	$ 172,748

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
LIFO reserve	$ 35,298,000	$ 33,518,000

Contingencies - Additional Info

Contingencies - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Site Contingency [Line Items]
Environmental and legal losses	$ 24,000,000		$ 24,200,000
Cash outlays related to legal and environmental matters	$ 1,000,000	$ 1,400,000
Contribution for future response costs	5.00%
Wilmington Site [Member]
Site Contingency [Line Items]
Payment of environmental response costs	$ 2,600,000
Minimum [Member]
Site Contingency [Line Items]
Environmental and legal losses	24,000,000
Maximum [Member]
Site Contingency [Line Items]
Environmental and legal losses	$ 45,500,000

Postretirement Benefit Plans -

Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (income)	$ 208	$ 125	$ 466	$ 468
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1,566	1,665	4,645	4,988
Expected return on plan assets	(2,320)	(2,323)	(6,962)	(6,966)
Amortization of net actuarial loss	987	738	2,860	2,314
Net periodic benefit cost (income)	233	80	543	336
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	138	151	430	441
Expected return on plan assets	(216)	(203)	(673)	(593)
Amortization of net actuarial loss	53	97	166	284
Net periodic benefit cost (income)	$ (25)	$ 45	$ (77)	$ 132

Postretirement Benefit Plans _2

Postretirement Benefit Plans - Defined Benefit Pension Plans - Additional Information (Detail)	3 Months Ended	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Defined Contribution Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance of trust assets	$ 1,617,000	$ 1,617,000
United States [Member] | Funded Plan [Member] | Qualified Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	5,000,000	5,000,000
Expected contribution to defined benefit plans	0	0
United States [Member] | Unfunded Plan [Member] | Non-qualified Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		256,000
Expected contribution to defined benefit plans	312,000	312,000
U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		372,000
Expected contribution to defined benefit plans	$ 497,000	$ 497,000

Postretirement Benefit Plans _3

Postretirement Benefit Plans - Defined Contribution Plan Expenses for the Company's Retirement Savings Plans and Profit Sharing (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Contribution Plan Disclosure [Line Items]
Total defined contribution expense	$ 2,497	$ 2,583	$ 7,970	$ 9,017
Retirement Savings Plans [Member]
Defined Contribution Plan Disclosure [Line Items]
Total defined contribution expense	1,738	1,275	5,201	3,758
Profit Sharing Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Total defined contribution expense	$ 759	$ 1,308	$ 2,769	$ 5,259

Earnings Per Share - Computatio

Earnings Per Share - Computations of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Computation of Basic Earnings per Share
Net income attributable to Stepan Company		$ 22,168	$ 21,899	$ 85,816	$ 81,694
Weighted-average number of common shares outstanding		22,986	22,971	23,036	22,941
Basic earnings per share		$ 0.96	$ 0.95	$ 3.73	$ 3.56
Computation of Diluted Earnings per Share
Net income attributable to Stepan Company		$ 22,168	$ 21,899	$ 85,816	$ 81,694
Weighted-average number of common shares outstanding		22,986	22,971	23,036	22,941
Add weighted-average net shares from assumed exercise of options (under treasury stock method)	[1]	103	147	103	167
Add weighted-average net shares related to unvested stock awards (under treasury stock method)		3	8	2	8
Weighted-average shares applicable to diluted earnings		23,288	23,374	23,324	23,361
Diluted earnings per share		$ 0.95	$ 0.94	$ 3.68	$ 3.50
Stock Appreciation Rights (SARs) [Member]
Computation of Diluted Earnings per Share
Add weighted-average net shares from assumed exercise of options (under treasury stock method)	[1]	113	140	111	142
Performance Stock Award [Member]
Computation of Diluted Earnings per Share
Add weighted-average net shares from assumed exercise of options (under treasury stock method)		83	108	72	103
[1]	Options/SARs to acquire 65,919 shares of Company common stock were excluded from the computations of diluted earnings per share for the nine months ended September 30, 2018. Options/SARs to acquire 24,840 shares of Company common stock were excluded from the computations of diluted earnings per share for the nine months ended September 30, 2017. Inclusion of the instruments would have had antidilutive effects on the computations of the earnings per share.

Earnings Per Share - Computat_2

Earnings Per Share - Computations of Basic and Diluted Earnings Per Share (Parenthetical) (Detail) - shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Options and Stock Appreciation Rights (SARs) [Member]
Earnings Per Share Basic [Line Items]
Options to purchase shares of common stock were excluded from the computations of diluted earnings per share	65,919	24,840

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			$ 740,096
Other comprehensive income before reclassifications	$ (2,503)	$ 9,811	(28,730)	$ 26,229
Amounts reclassified from AOCI	786	537	2,286	1,664
Net current-period other comprehensive income	(1,717)	10,348	(26,444)	27,893
Ending Balance	777,651		777,651
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(96,788)	(80,357)	(70,561)	(96,775)
Other comprehensive income before reclassifications	(2,503)	9,811	(28,730)	26,229
Net current-period other comprehensive income	(2,503)	9,811	(28,730)	26,229
Ending Balance	(99,291)	(70,546)	(99,291)	(70,546)
Defined Benefit Pension Plan Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(27,588)	(29,658)	(29,093)	(30,790)
Amounts reclassified from AOCI	788	539	2,293	1,671
Net current-period other comprehensive income	788	539	2,293	1,671
Ending Balance	(26,800)	(29,119)	(26,800)	(29,119)
Cash Flow Hedge Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	86	95	91	100
Amounts reclassified from AOCI	(2)	(2)	(7)	(7)
Net current-period other comprehensive income	(2)	(2)	(7)	(7)
Ending Balance	84	93	84	93
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(124,290)	(109,920)	(99,563)	(127,465)
Ending Balance	$ (126,007)	$ (99,572)	$ (126,007)	$ (99,572)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) - Summary of Amounts Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income Before Provision for Income Taxes		$ 25,243	$ 29,312	[1]	$ 105,404	$ 110,705	[1]
Tax benefit		(3,075)	(7,459)		(19,597)	(29,044)
Cost of Sales	[2]	423,872	412,238		1,264,223	1,193,501
Defined Benefit Pension Plan Adjustments [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension actuarial losses	[3],[4]	(1,040)	(835)		(3,026)	(2,598)
Tax benefit	[3]	252	296		733	927
Income applicable to common stock	[3]	(788)	(539)		(2,293)	(1,671)
Cash Flow Hedge Adjustments [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income Before Provision for Income Taxes	[3]	2	2		7	7
Income applicable to common stock	[3]	2	2		7	7
Cash Flow Hedge Adjustments [Member] | Foreign exchange contracts [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of Sales	[3]	2	2		7	7
Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income applicable to common stock	[3]	$ (786)	$ (537)		$ (2,286)	$ (1,664)
[1]	The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost
[2]	The 2017 amounts for the noted line items have been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of Accounting Standards Update (ASU) No. 2017-7, Compensation –Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.
[3]	Amounts in parentheses denote expense to statement of income.
[4]	This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 8 for additional details).

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Reporting - Operating S

Segment Reporting - Operating Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Net Sales	$ 507,997	$ 487,814	$ 1,527,198	$ 1,451,184
Surfactants [Member]
Segment Reporting Information [Line Items]
Net Sales	346,884	321,444	1,062,708	973,381
Polymers [Member]
Segment Reporting Information [Line Items]
Net Sales	141,646	147,754	404,446	415,551
Specialty Products [Member]
Segment Reporting Information [Line Items]
Net Sales	$ 19,467	$ 18,616	$ 60,044	$ 62,252

Segment Reporting - Reconciliat

Segment Reporting - Reconciliation of Segment Information to Consolidated Financial Statements (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	[2]	Sep. 30, 2018	Sep. 30, 2017	[2]
Segment Reporting Information [Line Items]
Operating income	[1]	$ 27,694	$ 30,434		$ 112,034	$ 115,797
Business restructuring expenses (Note 15)		(1,715)	(426)		(2,346)	(1,798)
Interest expense, net		(2,797)	(2,763)		(8,620)	(8,618)
Other, net	[1]	346	1,641		1,990	3,526
Income Before Provision for Income Taxes		25,243	29,312		105,404	110,705
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income		51,285	44,695		165,996	163,675
Operating Segments [Member] | Surfactants [Member]
Segment Reporting Information [Line Items]
Operating income		31,201	22,559		105,670	92,080
Operating Segments [Member] | Polymers [Member]
Segment Reporting Information [Line Items]
Operating income		17,431	21,146		53,783	63,884
Operating Segments [Member] | Specialty Products [Member]
Segment Reporting Information [Line Items]
Operating income		2,653	990		6,543	7,711
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Unallocated corporate expenses	[3]	$ (21,876)	$ (13,835)		$ (51,616)	$ (46,080)
[1]	The 2017 amounts for the noted line items have been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of Accounting Standards Update (ASU) No. 2017-7, Compensation –Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.
[2]	The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost
[3]	Unallocated corporate expenses are primarily comprised of corporate administrative expenses (e.g., corporate finance, legal, human resources, information systems, deferred compensation and environmental remediation) that are not included in segment operating income and not used to evaluate segment performance.

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018USD ($)
Disaggregation Of Revenue [Line Items]
Contract assets	$ 0
Contract liabilities	$ 0
Minimum [Member]
Disaggregation Of Revenue [Line Items]
Payment terms on sales of product	30 days
Maximum [Member]
Disaggregation Of Revenue [Line Items]
Payment terms on sales of product	60 days

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Summary of Geographic Disaggregation of Net Sales (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation Of Revenue [Line Items]
Net sales	$ 507,997	$ 487,814	$ 1,527,198	$ 1,451,184
North America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	309,629	286,106		879,792
Europe [Member]
Disaggregation Of Revenue [Line Items]
Net sales	116,490	125,734		356,201
Latin America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	59,538	52,559		146,881
Asia [Member]
Disaggregation Of Revenue [Line Items]
Net sales	22,340	23,415		68,310
Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales	346,884	321,444	1,062,708	973,381
Surfactants [Member] | North America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	205,032	184,889		582,148
Surfactants [Member] | Europe [Member]
Disaggregation Of Revenue [Line Items]
Net sales	68,120	69,325		198,037
Surfactants [Member] | Latin America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	58,560	51,241		143,305
Surfactants [Member] | Asia [Member]
Disaggregation Of Revenue [Line Items]
Net sales	15,172	15,989		49,891
Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales	141,646	147,754	404,446	415,551
Polymers [Member] | North America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	87,720	86,002		251,291
Polymers [Member] | Europe [Member]
Disaggregation Of Revenue [Line Items]
Net sales	45,780	53,008		142,265
Polymers [Member] | Latin America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	978	1,318		3,576
Polymers [Member] | Asia [Member]
Disaggregation Of Revenue [Line Items]
Net sales	7,168	7,426		18,419
Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales	19,467	18,616	$ 60,044	62,252
Specialty Products [Member] | North America [Member]
Disaggregation Of Revenue [Line Items]
Net sales	16,877	15,215		46,353
Specialty Products [Member] | Europe [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ 2,590	$ 3,401		$ 15,899

Debt - Debt (Detail)

Debt - Debt (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total debt	$ 286,237	$ 290,799
Less current maturities	23,686	22,500
Long-term debt	262,551	268,299
Unsecured private placement 3.95% note [Member]
Debt Instrument [Line Items]
Total debt	$ 99,630	$ 99,654
Debt instrument interest rate percentage	3.95%	3.95%
Unsecured private placement 3.95% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,021	2,021
Unsecured private placement 3.95% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,027	2,027
Unsecured private placement 3.86% note [Member]
Debt Instrument [Line Items]
Total debt	$ 99,639	$ 99,657
Debt instrument interest rate percentage	3.86%	3.86%
Unsecured private placement 3.86% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,019	2,019
Unsecured private placement 3.86% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,025	2,025
Unsecured private placement 4.86% note [Member]
Debt Instrument [Line Items]
Total debt	$ 55,519	$ 55,523
Debt instrument interest rate percentage	4.86%	4.86%
Unsecured private placement 4.86% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,018	2,018
Unsecured private placement 4.86% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,023	2,023
Unsecured private placement 5.88% note [Member]
Debt Instrument [Line Items]
Total debt	$ 22,764	$ 28,476
Debt instrument interest rate percentage	5.88%	5.88%
Unsecured private placement 5.88% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,018	2,018
Unsecured private placement 5.88% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2,022	2,022
Unsecured private placement 5.69% note [Member]
Debt Instrument [Line Items]
Total debt	$ 5,713	$ 5,703
Debt instrument interest rate percentage	5.69%	5.69%
Maturity Dates	2,018	2,018
Debt of foreign subsidiaries Unsecured bank debt, foreign currency [Member]
Debt Instrument [Line Items]
Total debt	$ 2,972	$ 1,786
Maturity Dates	2,018	2,018

Debt - Debt (Parenthetical) (De

Debt - Debt (Parenthetical) (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 1,021,000	$ 987,000
Unsecured private placement 3.95% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	371,000	346,000
Unsecured private placement 3.86% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	361,000	343,000
Unsecured private placement 4.86% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	195,000	191,000
Unsecured private placement 5.88% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	93,000	95,000
Unsecured private placement 5.69% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 1,000	$ 12,000

Debt - Additional Information (

Debt - Additional Information (Detail) - Multi currency revolving credit agreement [Member] - USD ($)	Jan. 30, 2018	Sep. 30, 2018	Jan. 29, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Revolving credit agreement term	5 years
Revolving credit agreement	$ 350,000,000		$ 125,000,000
Credit agreement secured date	Jan. 30, 2023
Letters of Credit Outstanding		$ 5,041,000
Debt Outstanding		0
Unused Revolving credit		344,959,000
Unrestricted retained earnings		$ 169,388,000		$ 190,495,000

Other, Net - Other Net in Conso

Other, Net - Other Net in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Other Nonoperating Income Expense [Abstract]
Foreign exchange gains (losses)		$ (274)	$ 596		$ 895	$ 97
Investment income		91	69		320	220
Realized and unrealized gains on investments		737	1,101		1,241	3,677
Net periodic benefit cost		(208)	(125)		(466)	(468)
Other, net	[1]	$ 346	$ 1,641	[2]	$ 1,990	$ 3,526	[2]
[1]	The 2017 amounts for the noted line items have been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of Accounting Standards Update (ASU) No. 2017-7, Compensation –Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.
[2]	The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

Business Restructuring - Additi

Business Restructuring - Additional Information (Detail)	1 Months Ended	3 Months Ended			9 Months Ended
	Jun. 30, 2017Employees	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	[1]	Sep. 30, 2018USD ($)Employees	Sep. 30, 2017USD ($)
Restructuring Cost And Reserve [Line Items]
Business restructuring		$ 1,715,000	$ 426,000		$ 2,346,000	$ 1,798,000	[1]
Germany [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring costs		1,410,000
Singapore [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Number positions eliminated | Employees	11
Restructuring liability		$ 0			$ 0
Singapore [Member] | Surfactants [Member] | Termination Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring						$ 132,000
Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Number positions eliminated | Employees					30
Business restructuring					$ 5,775,000
Longford Mills [Member] | Surfactants [Member] | Termination Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring					1,594,000
Longford Mills [Member] | Surfactants [Member] | Other Expense [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring					$ 4,181,000
[1]	The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

Business Restructuring - Reconc

Business Restructuring - Reconciliation of Restructuring Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended					9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	[1]	Sep. 30, 2018	Sep. 30, 2017	[1]
Restructuring Cost And Reserve [Line Items]
Expense recognized	$ 1,715			$ 426		$ 2,346	$ 1,798
Canada [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring liability	452	$ 493	$ 691			691
Expense recognized	305	273	358
Amounts paid	(367)	(305)	(549)
Foreign currency translation	7	(9)	(7)
Restructuring liability	397	452	493			397
Canada [Member] | Termination Benefits [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring liability	363	449	592			592
Amounts paid	(61)	(79)	(140)
Foreign currency translation	6	(7)	(3)
Restructuring liability	308	363	449			308
Canada [Member] | Other Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring liability	89	44	99			99
Expense recognized	305	273	358
Amounts paid	(306)	(226)	(409)
Foreign currency translation	1	(2)	(4)
Restructuring liability	$ 89	$ 89	$ 44			$ 89
[1]	The 2017 data has been immaterially changed from the amounts originally reported as a result of the Company’s first quarter 2018 adoption of ASU No. 2017-7, Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost

Acquisition - Additional Inform

Acquisition - Additional Information (Detail)	Mar. 26, 2018USD ($)ft²T	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Business Acquisition [Line Items]
Paid from cash on hand		$ 21,475,000	$ 4,339,000
BASF Mexicana, S.A. DE C.V. [Member]
Business Acquisition [Line Items]
Total assets acquired	$ 22,852,000
BASF Mexicana, S.A. DE C.V. [Member] | Surfactants [Member] | Ecatepec, Mexico [Member]
Business Acquisition [Line Items]
Incremental inventory and related value-added taxes		1,377,000
Capacity of production facility expected to be acquired | T	50,000
Warehouse space, laboratory and office space currently expected to be acquired | ft²	124,000
Paid from cash on hand	$ 21,475,000
Total assets acquired		$ 22,852,000

Acquisition - Summary of Assets

Acquisition - Summary of Assets Acquired Measured and Recorded at Estimated Fair Values (Detail) - BASF Mexicana, S.A. DE C.V. [Member] $ in Thousands	Mar. 26, 2018USD ($)
Assets:
Property, plant and equipment	$ 14,464
Inventory	5,687
Other Receivable	2,701
Total assets acquired	$ 22,852

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	12.20%	25.40%	18.60%	26.20%
Corporate tax rate			21.00%		35.00%
Expects repatriate			$ 100,000,000
Provisional transition tax obligation	$ 400,000		19,000,000		$ 19,400,000
Income tax expense	$ 400,000		$ 19,000,000		19,400,000
Measurement-period adjustment reduction of rate	0.40%		4.90%
Additional income tax expense	$ 1,900,000
Increase in effective tax rate			1.80%
Deferred income tax benefit					$ 4,500,000
Favorable measurement-period adjustment			$ 5,200,000
Tax Cuts And Jobs Act Of 2017 Income Tax Expense Benefit			$ 9,700,000
Deduction percent of qualified property			100.00%
Additional bonus depreciation			20.00%
Addition in valuation allowance	0		$ 0
Change in valuation allowance	$ 0		$ 0