Stepan (SCL) 10-K 27 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Jan. 30, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	SCL
Entity Registrant Name	STEPAN CO
Entity Central Index Key	94049
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		22,255,647
Entity Public Float			$1,016,145,805

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Statement [Abstract]
Net Sales (Note 1)	$1,927,213	[1]	$1,880,786	[1]	$1,803,737	[1]
Cost of Sales	1,677,650		1,599,101		1,512,184
Gross Profit	249,563		281,685		291,553
Operating Expenses:
Selling (Note 1)	54,763		53,229		53,145
Administrative (Note 1)	54,646		71,454		63,979
Research, development and technical services (Note 1)	45,451		46,809		45,713
Total Operating expenses	154,860		171,492		162,837
Business restructuring and asset impairments (Note 21)	4,009	[2]	1,040	[2]
Operating Income	90,694		109,153		128,716
Other Income (Expense):
Interest, net (Note 6)	-11,441		-10,358		-9,599
Loss from equity in joint ventures (Note 1)	-5,008		-5,336		-4,724
Other, net (Note 8)	1,290		2,171		1,329
Nonoperating Income (Expense), Total	-15,159		-13,523		-12,994
Income Before Provision for Income Taxes	75,535		95,630		115,722
Provision for Income Taxes (Note 9)	18,454		23,293		36,035
Net Income	57,081		72,337		79,687
Net (Income) Loss Attributable to Noncontrolling Interests (Note 1)	20		491		-291
Net Income Attributable to Stepan Company	$57,101		$72,828		$79,396
Net Income Per Common Share Attributable to Stepan Company (Note 18):
Basic	$2.51		$3.22		$3.71
Diluted	$2.49		$3.18		$3.49
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 18):
Basic	22,758		22,621		21,273
Diluted	22,917		22,924		22,730
[1]	Net sales are attributed to countries based on selling location.
[2]	See Note 21 regarding business restructuring and asset impairment costs.

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$57,081	$72,337	$79,687
Other Comprehensive Income (Loss):
Foreign currency translation adjustments (Note 19)	-31,980	-8,034	6,101
Defined benefit pension plans:
Net actuarial loss arising in period (net of taxes of $14,227, $7,783 and $2,568 for 2014, 2013 and 2012, respectively)	-24,186	13,417	-5,387
Amortization of prior service cost included in pension expense (net of taxes of $6, $6 and $5 for 2014, 2013 and 2012, respectively)	14	13	13
Amortization of actuarial loss included in pension expense (net of taxes of $1,032, $2,015 and $1,371 for 2014, 2013 and 2012, respectively)	1,695	3,395	2,261
Amortization of transition obligation included in pension expense (net of taxes of $0, $1 and $5 for 2014, 2013 and 2012, respectively)		1	13
Net defined benefit pension plan activity (Note 19)	-22,477	16,826	-3,100
Cash flow hedges:
Gains (losses) arising in period (net of taxes of $0, $0, $16 in 2014, 2013 and 2012, respectively)		-32	116
Reclassifications to income in period (net of taxes of $7, $14 and $8 in 2014, 2013 and 2012, respectively)	3	13	19
Net cash flow hedge activity (Note 19)	3	-19	135
Other Comprehensive Income (Loss)	-54,454	8,773	3,136
Comprehensive Income	2,627	81,110	82,823
Comprehensive (Income) Loss Attributable to Noncontrolling Interests	57	440	-389
Comprehensive Income Attributable to Stepan Company	$2,684	$81,550	$82,434

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net actuarial loss arising in period, tax	($14,227)	$7,783	($2,568)
Amortization of prior service cost included in pension expense, tax	6	6	5
Amortization of actuarial loss included in pension expense, tax	1,032	2,015	1,371
Amortization of transition obligation included in pension expense, tax	0	1	5
Gains (losses) arising in period, tax	0	0	16
Reclassifications to income in period, tax	$7	$14	$8

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets:
Cash and cash equivalents	$85,215	$133,347
Receivables, less allowances of $10,011 in 2014 and $5,945 in 2013	270,436	265,721
Inventories (Note 5)	183,233	172,368
Deferred income taxes (Note 9)	15,364	12,637
Other current assets	21,308	24,477
Total current assets	575,556	608,550
Property, Plant and Equipment:
Land	12,446	13,008
Buildings and improvements	171,559	162,199
Machinery and equipment	1,119,400	1,085,763
Construction in progress	82,446	55,529
Property, Plant and Equipment, Gross	1,385,851	1,316,499
Less: accumulated depreciation	-861,656	-822,457
Property, plant and equipment, net	524,195	494,042
Goodwill, net (Note 4)	11,502	11,726
Other intangible assets, net (Note 4)	20,803	23,669
Long-term investments (Note 2)	20,217	18,305
Other non-current assets	9,741	10,910
Total Assets	1,162,014	1,167,202
Current Liabilities:
Current maturities of long-term debt (Note 6)	27,034	35,377
Accounts payable	156,983	157,277
Accrued liabilities (Note 14)	65,496	76,339
Total current liabilities	249,513	268,993
Deferred income taxes (Note 9)	15,804	20,616
Long-term debt, less current maturities (Note 6)	246,897	235,246
Other non-current liabilities (Note 15)	112,856	88,606
Commitments and Contingencies (Note 16)
Equity (Note 10):
Common stock, $1 par value; authorized 60,000,000 shares; issued 25,640,090 shares in 2014 and 25,563,909 shares in 2013	25,640	25,564
Additional paid-in capital	139,573	135,693
Accumulated other comprehensive loss (Note 19)	-83,945	-29,528
Retained earnings	520,540	478,826
Less: Common treasury stock, at cost, 3,384,443 shares in 2014 and 3,231,289 shares in 2013	-66,262	-58,269
Total Stepan Company stockholders’ equity	535,546	552,286
Noncontrolling interests	1,398	1,455
Total equity	536,944	553,741
Total Liabilities and Equity	$1,162,014	$1,167,202

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]
Allowances	$10,011	$5,945
Common stock, par value	$1	$1
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	25,640,090	25,563,909
Treasury stock, shares	3,384,443	3,231,289

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows From Operating Activities
Net income	$57,081	$72,337	$79,687
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	63,804	56,400	51,294
Deferred compensation	-11,903	9,496	10,252
Realized and unrealized gain on long-term investments	-241	-2,611	-1,460
Stock-based compensation	-68	2,783	3,122
Deferred income taxes	5,306	259	134
Other non-cash items	8,260	7,253	2,755
Changes in assets and liabilities, excluding effects of acquisitions:
Receivables, net	-21,229	-12,749	3,906
Inventories	-18,521	-3,794	-50,260
Other current assets	1,430	-5,950	-2,210
Accounts payable and accrued liabilities	-4,376	26,256	24,055
Pension liabilities	-2,709	1,997	-4,341
Environmental and legal liabilities	6,493	-353	-66
Deferred revenues	-732	2,428	-662
Excess tax benefit from stock options and awards	-640	-3,438	-7,237
Net Cash Provided By Operating Activities	81,955	150,314	108,969
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	-101,819	-92,865	-83,159
Business acquisitions, net of cash acquired (Note 20)		-68,212
Sale of mutual funds	908	698	537
Other, net	-8,310	-7,179	-4,827
Net Cash Used In Investing Activities	-109,221	-167,558	-87,449
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net	14,219	4,820	770
Other debt borrowings	4,923	100,000
Other debt repayments	-12,656	-17,618	-18,460
Dividends paid	-15,387	-14,474	-12,757
Company stock repurchased	-7,924	-2,275	-2,098
Stock option exercises	1,754	3,977	4,473
Excess tax benefit from stock options and awards	640	3,438	7,237
Other, net	-421	-1,615	-8,640
Net Cash Provided By (Used In) Financing Activities	-14,852	76,253	-29,475
Effect of Exchange Rate Changes on Cash	-6,014	-2,537	731
Net Increase (Decrease) in Cash and Cash Equivalents	-48,132	56,472	-7,224
Cash and Cash Equivalents at Beginning of Year	133,347	76,875	84,099
Cash and Cash Equivalents at End of Year	85,215	133,347	76,875
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds	23,142	22,691	29,698
Cash payments of interest	$12,447	$11,281	$10,491

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (USD $)	Total	Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interests' Equity [Member]
In Thousands, unless otherwise specified
Balance at Dec. 31, 2011	$405,465	$12,957	$11,709	$94,932	($43,195)	($41,485)	$366,293	$4,254
Issuance of common stock under stock option plan	8,806		321	8,485
Purchase of common stock	-11,759				-11,759
Purchase of remaining interest in Stepan Philippines, Inc. from noncontrolling interest	-2,000			551		197		-2,748
Conversion of preferred stock to common stock		-11,409	604	10,805
Stock-based and deferred compensation	3,065		48	2,993	24
Net Income	79,687						79,396	291
Other comprehensive income	3,136					3,038		98
Cash dividends paid:
Preferred stock	-579						-579
Common stock	-12,178						-12,178
Non-qualified stock option and stock award income tax benefit	7,237			7,237
Two-for-one stock split			12,460				-12,460
Balance at Dec. 31, 2012	480,880	1,548	25,142	125,003	-54,930	-38,250	420,472	1,895
Issuance of common stock under stock option plan	4,069		227	3,842
Purchase of common stock	-3,425				-3,425
Redemption of preferred stock	-21	-21
Conversion of preferred stock to common stock		-1,527	140	1,387
Stock-based and deferred compensation	2,162		55	2,021	86
Net Income	72,337						72,828	-491
Other comprehensive income	8,773					8,722		51
Cash dividends paid:
Preferred stock	-43						-43
Common stock	-14,431						-14,431
Non-qualified stock option and stock award income tax benefit	3,440			3,440
Balance at Dec. 31, 2013	553,741		25,564	135,693	-58,269	-29,528	478,826	1,455
Issuance of common stock under stock option plan	1,754		67	1,687
Purchase of common stock	-7,924				-7,924
Stock-based and deferred compensation	1,493		9	1,553	-69
Net Income	57,081						57,101	-20
Other comprehensive income	-54,454					-54,417		-37
Cash dividends paid:
Common stock	-15,387						-15,387
Non-qualified stock option and stock award income tax benefit	640			640
Balance at Dec. 31, 2014	$536,944		$25,640	$139,573	($66,262)	($83,945)	$520,540	$1,398

Consolidated_Statements_of_Equ1

Consolidated Statements of Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of shares of common stock issued under stock option plan	67,029	227,410	582,730
Number of common stock shares purchased	154,633	60,595	251,312
Preferred stock		$1.38	$1.38
Common stock	$0.69	$0.65	$0.58
Common Stock Split Ratio Declared			2
Common Stock [Member]
Number of shares of common stock issued under stock option plan	67,029	227,410	582,730
Additional Paid-in Capital [Member]
Number of shares of common stock issued under stock option plan	67,029	227,410	582,730
Treasury Stock [Member]
Number of common stock shares purchased	154,633	60,595	251,312

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies
	Nature of Operations
	Stepan Company (the Company) operations consist predominantly of the production and sale of specialty and intermediate chemicals, which are sold to other manufacturers for use in a variety of end products. Principal markets for all products are manufacturers of cleaning and washing compounds (including detergents, shampoos, fabric softeners, toothpastes and household cleaners), paints, cosmetics, food, beverages, nutritional supplements, agricultural products, plastics, furniture, automotive equipment, insulation and refrigeration.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires Company management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and all wholly and majority-owned subsidiaries in which the Company exercises controlling influence. The equity method is used to account for investments in which the Company exercises significant but noncontrolling influence. Intercompany balances and transactions are eliminated in consolidation.
	The Company is a partner in two joint ventures: Nanjing Stepan Jinling Chemical Limited Liability Company (Stepan China) in Nanjing, China, and TIORCO, LLC in Denver, Colorado. The Company has an 80 percent ownership interest in the Stepan China joint venture and exercises controlling influence. Therefore, Stepan China’s accounts are included in the Company’s consolidated financial statements. The joint venture partner’s interest in Stepan China’s net income is reported in the net income attributable to noncontrolling interests line of the consolidated statements of income. The joint venture partner’s interest in the net assets of Stepan China is reported in the noncontrolling interests line (a component of equity separate from Company equity) of the consolidated balance sheets.
	TIORCO, LLC is equally owned and controlled by the Company and Nalco Company (a subsidiary of Ecolab Inc.). The Company’s investment in TIORCO, LLC is accounted for using the equity method and is included in the other non-current assets line on the consolidated balance sheets. The Company’s share of TIORCO, LLC’s net earnings is included in the loss from equity in joint ventures line of the consolidated statements of income.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with purchased maturities of three months or less to be cash equivalents.
	At December 31, 2014, the Company’s cash and cash equivalents totaled $85.2 million.  Cash in U.S. demand deposit accounts totaled $8.4 million and cash of the Company’s non-U.S. subsidiaries held outside the U.S. totaled $76.8 million as of December 31, 2014.
	Receivables and Credit Risk
	Receivables are stated net of allowances for doubtful accounts and other allowances and primarily include trade receivables from customers, as well as nontrade receivables from suppliers, governmental tax agencies and others.
	The Company is exposed to credit risk on accounts receivable balances. This risk is mitigated by the Company’s large, diverse customer base, which is dispersed over various geographic regions and industrial sectors. No single customer comprised more than 10 percent of the Company’s consolidated net sales in 2014, 2013 or 2012.
	The Company maintains allowances for potential credit losses. Specific customer allowances are recorded when a review of customer creditworthiness and current economic conditions indicate that collection is doubtful. In addition, the Company maintains a general allowance as a percentage of total trade receivables. The general allowance percentage is periodically reviewed and adjusted based on historical bad debt losses of the Company.
	The Company also maintains other customer allowances that occur in the normal course of business. Such allowances are based on historical averages and trade receivable levels.
	The following is an analysis of the allowance for doubtful accounts and other accounts receivable allowances for the years ended December 31, 2014, 2013 and 2012:
	(In thousands)	2014			2013			2012
	Balance at January 1	$	5,945		$	5,533		$	5,214
	Provision charged to income		4,625			719			314
	Accounts written off, net of recoveries		(559	)		(307	)		5
	Balance at December 31	$	10,011		$	5,945		$	5,533
	The 2014 provision charged to income included a $2,388,000 bad debt allowance for a major Polymer customer that filed for protection under Chapter 11 of the U.S. Bankruptcy Code in September 2014. Also included in the 2014 provision charged to income were additional allowances for certain high risk accounts and for general reserves.
	Inventories
	Inventories are valued at cost, which is not in excess of market value, and include material, labor and plant overhead costs. The last-in, first-out (LIFO) method is used to determine the cost of the Company’s U.S. inventories. The first-in, first-out (FIFO) method is used for all other inventories. Inventories priced at LIFO as of December 31, 2014 and 2013, accounted for 67 and 64 percent of total inventories, respectively.
	Property, Plant and Equipment
	Depreciation of property, plant and equipment is provided on a straight-line basis over the estimated useful lives of the assets. Lives used for calculating depreciation are generally 30 years for buildings and 15 years for building improvements. For assets classified as machinery and equipment, lives generally used for calculating depreciation expense range from 10 to 15 years for manufacturing equipment, five to 10 years for furniture and fixtures, three to five years for vehicles and three to 10 years for computer equipment and software. Manufacturing of chemicals is capital intensive with a large majority of the assets included in machinery and equipment representing manufacturing equipment. Major renewals and betterments are capitalized in the property accounts, while maintenance and repairs ($55,923,000, $48,683,000, and $45,072,000 in 2014, 2013 and 2012, respectively), which do not renew or extend the life of the respective assets, are charged to operations as incurred. Land is not depreciated. The cost of property retired or sold and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in income.
	Included in the computer equipment and software component of machinery and equipment are costs related to the acquisition and development of internal-use software. Capitalized costs for internal-use software include external direct costs of materials and services consumed in obtaining and developing the software. For development projects where major internal resources are committed, payroll and payroll-related costs incurred during the application development phase of the project are also capitalized. The capitalized costs are amortized over the useful lives of the software, which are generally three to 10 years. Costs incurred in the preliminary project phase are expensed.
	Interest charges on borrowings applicable to major construction projects are capitalized.
	Property, plant and equipment assets are tested for impairment when events indicate that impairment may have occurred.
	Fair Value Measurements
	GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Furthermore, GAAP establishes a framework, in the form of a three-level hierarchy, for measuring fair value that prioritizes the inputs to valuation techniques used to measure fair value. The following describes the hierarchy levels:
	Level 1 - quoted prices in active markets for identical assets and liabilities.
	Level 2 - inputs other than quoted prices included within Level 1 that are directly or indirectly observable for the asset or liability, such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data.
	Level 3 - unobservable inputs which reflect the entity’s own assumptions about the assumptions market participants use in pricing the assets and liabilities.
	The Company applies the fair value measurement provisions of GAAP to any of its financial assets and liabilities that are carried at fair value on the consolidated balance sheets (see Note 2), its outstanding debt for disclosure purposes (also Note 6) and its pension plan assets (see Note 13).
	The Company also applies the fair value measurement requirements to nonrecurring fair value measurements of nonfinancial assets and liabilities recorded in conjunction with business combinations and as part of impairment reviews for goodwill and other long-lived assets.
	Revenue Recognition
	Revenue is recognized upon shipment of goods to customers, at which time title and risk of loss pass to the customer. For arrangements where the Company consigns product to a customer location, revenue is recognized when the customer uses the inventory. The Company records shipping and handling billed to a customer in a sales transaction as revenue. Costs incurred for shipping and handling are reported in cost of sales. Volume discounts due customers are estimated and recorded in the same period as the sales to which the discounts relate and reported as reductions of revenue in the consolidated statements of income.
	Cost of Sales
	Cost of sales comprises raw material costs (including inbound freight expense to deliver the raw materials), manufacturing plant labor expenses and various manufacturing overhead expenses, such as utility, maintenance, operating supply, amortization and manufacturing asset depreciation expenses. Cost of sales also includes outbound shipping and handling expenses, inter-plant transfer costs and warehouse expenses.
	Operating Expenses
	Selling expense comprises salary and the related fringe benefit expenses for marketing and sales personnel and operating costs, such as outside agent commissions, automobile rental and travel-related expenses, which support the sales and marketing functions. Bad debt charges and any depreciation expenses related to marketing assets (e.g., computers) are also classified as selling expense.
	Administrative expense comprises salary and the related fringe benefit expenses and operating costs for the Company’s various administrative functions, which include information services, finance, legal, and human resources. Compensation expense related to the Company’s deferred compensation plans and legal and environmental remediation expenses are also classified as administrative expense.
	The Company’s research and development costs are expensed as incurred. These expenses are aimed at discovery and commercialization of new knowledge with the intent that such effort will be useful in developing a new product or in bringing about a significant improvement to an existing product or process. Total research and development expenses were $27,236,000, $28,782,000 and $28,032,000 in 2014, 2013 and 2012, respectively. The remainder of research, development and technical service expenses reflected on the consolidated statements of income relates to technical services, which include routine product testing, quality control and sales support service.
	Environmental Expenditures
	Environmental expenditures that relate to current operations are expensed in cost of sales. Expenditures that mitigate or prevent environmental contamination and that benefit future operations are capitalized as assets and depreciated on a straight-line basis over the estimated useful lives of the assets, which are typically 10 years.
	Estimated future expenditures that relate to an existing condition caused by past operations, and which do not contribute to current or future revenue generation, are recorded as liabilities, with the corresponding charge recorded in administrative expenses, when environmental assessments and/or remedial efforts are probable and the cost or range of possible costs can be reasonably estimated. When no amount within the range is a better estimate than any other amount, the minimum amount in the range is accrued. Some of the factors on which the Company bases its estimates include information provided by feasibility studies, potentially responsible party negotiations and the development of remedial action plans. Legal costs related to environmental matters are expensed as incurred (see Note 16 for environmental contingencies).
	Goodwill and Other Intangible Assets
	The Company’s intangible assets include patents, agreements not to compete, trademarks, customer lists, technological and manufacturing know-how and goodwill, all of which were acquired as part of business or product line acquisitions. Intangible assets other than goodwill are determined to have either finite or indefinite useful lives. The Company currently has no indefinite-life intangible assets. The values for intangible assets with finite lives are amortized over the useful lives of the assets. In addition, finite-life intangible assets are tested for impairment when events or changes in circumstances indicate that the carrying value of an intangible asset may not be recoverable. Goodwill is not amortized. Goodwill is tested for impairment at least annually or more frequently if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit to which goodwill relates below the reporting unit’s carrying value. For more details see Note 4.
	Income Taxes
	The provision for income taxes is determined using the asset and liability method, under which deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. Deferred tax assets or liabilities are computed using the currently enacted tax rates that apply to taxable income in effect for the years in which those tax assets and liabilities are expected to be realized or settled. Deferred tax assets and liabilities are adjusted for changes in tax rates or laws, and the effects of the changes are recorded in income in the period of enactment. Valuation allowances are recorded to reduce deferred tax assets when the Company determines that it is more likely than not that a tax benefit will not be realized.
	The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained upon examination by tax authorities. If the tax position meets the more-likely-than-not threshold, the tax benefit recognized in the consolidated financial statements is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon effective settlement. Unrecognized tax benefits, which are differences between the tax position taken on a tax return and the amounts recognized in the financial statements, are recorded either as an increase to a tax liability or as a decrease to an income tax receivable. The Company includes estimated interest and penalty amounts related to the unrecognized tax benefits in the tax provision.
	See Note 9 for detailed information about income taxes.
	Translation of Foreign Currencies
	For the Company’s consolidated foreign subsidiaries whose functional currency is the local foreign currency, assets and liabilities are translated into U.S. dollars at exchange rates in effect at year end and revenues and expenses are translated at average exchange rates for the year. Any resulting translation adjustments are included in the consolidated balance sheets in the accumulated other comprehensive loss line of stockholders’ equity. Gains or losses on foreign currency transactions are reflected in the other, net caption of the consolidated statements of income. The Company has one foreign subsidiary whose functional currency is the U.S. dollar. For this subsidiary, nonmonetary assets and liabilities are translated at historical rates, monetary assets and liabilities are translated at exchange rates in effect at year end, revenues and expenses are translated at average exchange rates for the year and translation gains and losses are included in the other, net caption of the consolidated statements of income.
	Stock-Based Compensation
	The Company grants stock options, performance stock awards and stock appreciation rights (SARs) to certain employees under its incentive compensation plans. The Company calculates the fair values of stock options, performance stock awards and SARs on the date such instruments are granted. The fair values of the stock option and performance stock awards are then recognized as compensation expense over the vesting periods of the instruments. The Company’s SARs are cash-settled and accounted for as liabilities that must be re-measured at fair value at the end of each reporting period. Compensation expense for each reporting period is calculated as the period-to-period change (or portion of the change, depending on the proportion of the vesting period that has been completed at the reporting date) in the fair value of the SARs. See Note 11 for detailed information about the Company’s stock-based compensation.
	Earnings Per Share
	Basic earnings per share amounts are computed based on the weighted-average number of common shares outstanding. Net income used in computing basic earnings per share is net income attributable to the Company reduced by dividends paid to preferred stockholders. Diluted earnings per share amounts are based on the weighted-average number of common shares outstanding plus the increased number of common shares that would be outstanding assuming the exercise of certain outstanding stock options (under the treasury stock method), the conversion of the convertible preferred stock (when such conversion would have the effect of reducing earnings per share), and contingent stock awards that are part of the Company’s incentive stock-based compensation program (see Note 11). See Note 18 for detailed information about the Company’s earnings per share calculations.
	Comprehensive Income and Accumulated Other Comprehensive Income
	Comprehensive income includes net income and all other non-owner changes in equity that are not reported in net income. Comprehensive income is disclosed in the consolidated statements of comprehensive income. Accumulated other comprehensive income (AOCI) is reported as a component of stockholders’ equity in the Company’s consolidated balance sheets. See Note 19 for detailed information regarding changes in the Company’s AOCI and reclassifications out of AOCI to income.
	Segment Reporting
The Company reports financial and descriptive information about its reportable operating segments. Operating segments are components of the Company that have separate financial information that is regularly evaluated by the chief operating decision maker to assess segment performance and allocate resources. The Company discloses segment revenue, operating income, assets, capital expenditures and depreciation and amortization expenses. Enterprise-wide financial information about the geographic locations in which the Company earns revenues and holds assets is also disclosed (see Note 17).
Derivative Instruments
Derivative instruments are recognized in the consolidated balance sheets as either assets or liabilities measured at fair value. For derivative instruments that are not designated as hedging instruments, changes in the fair values of the derivative instruments are recognized currently in earnings. For derivative instruments designated as hedging instruments, depending on the nature of the hedge, changes in the fair values of the derivative instruments are either offset in earnings against changes in the fair values of the hedged items or recognized in AOCI until the hedged transaction is recognized in earnings. At the time a hedging relationship is designated, the Company establishes the method it will use for assessing the effectiveness of the hedge and the measurement approach for determining the ineffective aspect of the hedge.   Company policy prohibits the use of derivative instruments for trading or speculative purposes. See Note 3 for further information regarding the Company’s use of derivatives.
At December 31, 2014, the Company held open forward contracts for the purchase of 1.6 million dekatherms of natural gas in 2015 and 2016 at a cost of $6,558,000. The Company uses forward contracts to minimize its exposure to volatile natural gas prices. Because the Company anticipates taking delivery of the natural gas for use in its operations, the forward contracts qualify for the normal purchase exception election provided under U.S. GAAP for derivative instruments. The Company has elected the exceptions for such contracts. As a result, the forward contracts are not accounted for as derivative instruments. The cost of natural gas is charged to expense at the time the natural gas is delivered and used.
Recent Accounting Pronouncements
In February 2013, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2013-04, Liabilities (Topic 405), Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date. This update requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date, as the sum of a) the amount the reporting entity agreed to pay on the basis of its arrangement among its co-obligors and b) any additional amount the reporting entity expects to pay on behalf of its co-obligors. The update also requires an entity to disclose the nature and amount of the obligation as well as other information about those obligations. The requirements of ASU No. 2013-04 were effective on a retrospective basis for interim and annual periods beginning after December 15, 2013. Because the Company had no applicable obligations resulting from joint and several liability arrangements, adoption of ASU No. 2013-04 did not impact on the Company’s financial position, results of operations or cash flows.
In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740), Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The update clarifies that unrecognized tax benefits related to a net operating loss carryforward, or similar tax loss, or tax credit carryforward, should generally be presented in the financial statements as a reduction to a deferred tax asset. The requirements of ASU No. 2013-11 were effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. Because the Company had no unrecognized tax benefits in jurisdictions where a net operating loss carryforward, or similar tax loss, or tax credit carryforward existed, adoption of the new guidance had no impact on the Company’s financial position, results of operations or cash flows.
In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The update amends the definition of a discontinued operation, changes the criteria for reporting discontinued operations and requires expanded disclosures for discontinued operations and new disclosures about disposal transactions that do not meet the discontinued operations criteria. Under the new guidance, a discontinued operation is defined as a disposal of a component or group of components that is disposed of or is classified as held for sale and represents a strategic shift that has or will have a major effect on an entity's operations and financial results. The requirements of ASU No. 2014-08 are effective for fiscal years, and interim periods within those years, beginning after December 15, 2014, with early adoption permitted. Upon adoption of the ASU, the Company will assess discontinued operations using the new criteria and will provide the necessary disclosures for discontinued operations and other disposal activities. This ASU is not expected to have an effect on the Company’s financial position, results of operations or cash flows.
In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The standard, which is the result of a joint project by the FASB and the International Accounting Standards Board, outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. In addition, the ASU requires expanded disclosures about revenue recognition that enable the users of the financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. ASU No. 2014-09 supersedes most of the previous revenue recognition guidance. For public entities, the new guidance is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. An entity may use either a full retrospective or a modified retrospective approach to adopt the requirements of the new standard. The Company is in the process of determining the effects, if any, that adoption of ASU No. 2014-09 will have on Company financial position, results of operations and cash flows.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	2. Fair Value Measurements
	The following are the financial instruments held by the Company at December 31, 2014 and 2013, and descriptions of 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 relate to the foreign currency exchange and interest rate contracts discussed in Note 3. 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. The fair values of the interest rate swaps were calculated as the difference between the contracted swap rate and the current market replacement swap rate multiplied by the present value of one basis point for the notional amount of the contract. 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 are the mutual fund assets the Company holds 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 13). Fair value and carrying value were the same because the mutual fund assets were recorded at fair value in accordance with the FASB’s fair value option rules. 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 in level 2 of the fair value hierarchy.
	At December 31, 2014 and 2013, the fair values and related carrying values of debt, including current maturities, were as follows:
	(In thousands)	31-Dec
		2014		2013
	Fair value	$	285,441	$	276,069
	Carrying value		273,931		270,623
	The following tables present financial assets and liabilities measured on a recurring basis at fair value as of December 31, 2014 and 2013, and the level within the fair value hierarchy in which the fair value measurement falls:
	(In thousands)	December		Level 1		Level 2		Level 3
		2014
	Mutual fund assets	$	20,217	$	20,217	$	─	$	─
	Derivative assets:
	Foreign currency contracts		73		─		73		─
	Total assets at fair value	$	20,290	$	20,217	$	73	$	─
	Derivative liabilities:
	Foreign currency contracts	$	628	$	─	$	628	$	─
	(In thousands)	December		Level 1		Level 2		Level 3
		2013
	Mutual fund assets	$	18,305	$	18,305	$	—	$	—
	Derivative assets:
	Foreign currency contracts		74		—		74		—
	Total assets at fair value	$	18,379	$	18,305	$	74	$	—
	Derivative liabilities:
	Foreign currency contracts	$	165	$	—	$	165	$	—
	Interest rate contracts		20		—		20		—
	Total liabilities at fair value	$	185	$	—	$	185	$	—

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments	3. 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 U.S. generally accepted accounting principles. 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 receivable and payable balances into the applicable functional currencies. At December 31, 2014 and 2013, the Company had open forward foreign currency exchange contracts, all with settlement dates of about one month, to buy or sell foreign currencies with a U.S. dollar equivalent of $51,623,000 and $20,289,000, respectively.
	The Company is exposed to volatility in short-term interest rates and, at times, mitigates certain portions of that risk using interest rate swaps and designating such swaps as cash flow hedges. The interest rate swaps are recognized on the balance sheet as either an asset or a liability measured at fair value. Period-to-period changes in the fair value of interest rate swap hedges are recognized as gains or losses in other comprehensive income, to the extent effective. As each interest rate swap hedge contract is settled, the corresponding gain or loss is reclassified out of AOCI into earnings in that settlement period. At December 31, 2014, the Company held no significant interest rate swap contracts. At December 31, 2013, the Company held interest rate swap contracts with notional values of $2,268,000.
	The fair values of the derivative instruments held by the Company on December 31, 2014, and December 31, 2013, and derivative instrument gains and losses for the years ended December 31, 2014, 2013 and 2012, were immaterial. For amounts reclassified out of AOCI into earnings for the years ended December 31, 2014, 2013 and 2012, see Note 19.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	4. Goodwill and Other Intangible Assets
	The changes in the carrying value of goodwill for the years ended December 31, 2014 and 2013, were as follows:
	(In thousands)		Surfactants						Polymer					Specialty Products				Total
			Segment						Segment					Segment
			2014			2013			2014			2013		2014		2013		2014			2013
	Balance as of January 1
	Goodwill		$	9,107		$	9,246		$	5,603		$	937	$	483	$	483	$	15,193		$	10,666
	Accumulated impairment loss			(3,467	)		(3,467	)		—			—		—		—		(3,467	)		(3,467	)
	Goodwill, net			5,640			5,779			5,603			937		483		483		11,726			7,199
	Goodwill acquired (1)			—			—			—			4,642		—		—		—			4,642
	Foreign currency translation			(82	)		(139	)		(142	)		24		—		—		(224	)		(115	)
	Balance as of December 31
	Goodwill			9,025			9,107			5,461			5,603		483		483		14,969			15,193
	Accumulated impairment loss			(3,467	)		(3,467	)		—			—		—		—		(3,467	)		(3,467	)
	Goodwill, net		$	5,558		$	5,640		$	5,461		$	5,603	$	483	$	483	$	11,502		$	11,726
	-1	See Note 20 for information regarding the goodwill acquired in business combinations.
	The Company tests its goodwill balances for impairment in the second quarter of each calendar year. The 2014 and 2013 tests indicated no impairment.
	The following table presents the components of other intangible assets, all of which have finite lives, as of December 31, 2014 and 2013. The year-over-year changes in gross carrying values resulted from the effects of foreign currency translation.
	(In thousands)		Gross Carrying Value						Accumulated Amortization
			31-Dec						31-Dec
			2014			2013			2014			2013
	Other Intangible Assets:
	Patents		$	6,947		$	6,947		$	2,096		$	1,498
	Trademarks			4,087			4,087			748			345
	Customer lists			8,082			8,094			1,871			1,098
	Know-how (a)			8,273			8,313			1,871			831
	Total		$	27,389		$	27,441		$	6,586		$	3,772
	(a)	Know-how includes intellectual property rights covering proprietary information, written formulae, trade secrets or secret processes, inventions and developmental products (whether patentable or not), discoveries, improvements, compositions, manufacturing processes, manuals, specifications and technical data.
	Aggregate amortization expense for the years ended December 31, 2014, 2013 and 2012, was $2,841,000, $2,832,000 and $2,516,000, respectively. Estimated amortization expense for identifiable intangibles assets for each of the five succeeding fiscal years is as follows:
	(In thousands)
	For year ended 12/31/15		$	2,825
	For year ended 12/31/16			2,681
	For year ended 12/31/17			2,565
	For year ended 12/31/18			2,565
	For year ended 12/31/19			2,565

Inventories

Inventories	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventories	5. Inventories
	The composition of inventories was as follows:
		December 31
	(In thousands)	2014		2013
	Finished products	$	126,157	$	123,211
	Raw materials		57,076		49,156
	Total inventories	$	183,233	$	172,368
	Inventories are primarily priced using the last-in, first-out (LIFO) inventory valuation method. If the first-in, first-out (FIFO) inventory valuation method had been used for all inventories, inventory balances would have been approximately $34,340,000 and $30,786,000 higher than reported at December 31, 2014 and 2013, respectively.

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt	6. Debt
	Debt comprised the following at December 31, 2014 and 2013:
	(In thousands)	Maturity			December 31,			December 31,
		Dates			2014			2013
	Unsecured private placement notes
	3.86%		2019-2025		$	100,000		$	100,000
	4.86%		2017-2023			65,000			65,000
	5.88%		2016-2022			40,000			40,000
	5.69%		2015-2018			22,857			28,571
	6.86%		2015			4,284			8,570
	Unsecured U.S. bank debt		2019			20,000			─
	Debt of foreign subsidiaries
	Unsecured bank debt, foreign currency		2015			12,043			19,488
	Unsecured bank term loan, foreign currency		2021			4,840			─
	Secured bank term loan, foreign currency		2015			2,723			5,843
	Secured bank debt, foreign currency		2015			1,638			2,153
	Unsecured bank debt, U.S. dollars		2015			546			998
	Total debt				$	273,931		$	270,623
	Less current maturities					27,034			35,377
	Long-term debt				$	246,897		$	235,246
	The majority of the Company’s long-term debt financing is composed of unsecured private placement notes issued to insurance companies, totaling $232,141,000 as of December 31, 2014. These notes are denominated in U.S. dollars and have fixed interest rates ranging from 3.86 percent to 6.86 percent. At inception, these notes had final maturities of 12 to 13 years with remaining amortization scheduled from 2015 to 2025.
	On July 10, 2014, the Company amended its committed $125,000,000 multi-currency five-year revolving credit agreement.  This unsecured facility is the Company’s primary source of short-term borrowings, which the Company may draw on as needed to finance certain acquisitions, working capital and for general corporate purposes. The amendment extends the maturity date of the original agreement from September 20, 2017 to July 10, 2019. As of December 31, 2014, the Company had outstanding borrowings of $20,000,000 and letters of credit of $2,727,000  under the credit agreement, with $102,273,000 remaining available.
	Loans under the amended agreement may be incurred, at the discretion of the Company, with terms to maturity of 1 to 180 days. The Company may choose interest rate options, including (1) LIBOR applicable to each currency plus spreads ranging from 0.975 percent to 1.525 percent, depending on the Company’s leverage ratio or (2) the prime rate plus zero percent to 0.525 percent, depending on the leverage ratio. The amended agreement requires the Company to pay a facility fee ranging from 0.150 percent to 0.350 percent, which also depends on the leverage ratio. The amended agreement requires the maintenance of certain financial ratios and compliance with certain other covenants that are similar to the Company’s existing debt agreements, including net worth, interest coverage and leverage financial covenants and limitations on restricted payments, indebtedness and liens.
	At December 31, 2014, European debt included $7,563,000 of bank term loans. One of these term loans, for $4,840,000 matures in 2021 and has a variable interest rate of 90-day EURIBOR plus a spread of 1.30 percent. The other term loan, for $1,815,000, matures in 2016 and has a variable interest rate of 90-day EURIBOR plus a spread of 1.08 percent. The other term loan for, $908,000, matures in 2015 and bears a fixed interest rate of 2.15 percent. At December 31, 2014, debt in Europe also included short-term borrowings of $11,842,000 with variable interest rates of 90-day EURIBOR plus spreads ranging from 0.30 percent and 0.50 percent and short-term borrowings of $1,638,000 with a variable rate comprised of the UK base rate plus a spread of 2.00 percent. The Company’s Philippine subsidiary had short-term borrowings of $747,000, guaranteed by the Company, with a variable interest rate of 30-day LIBOR plus a spread of 1.375 percent. The balance of the Company’s secured foreign debt is secured only by the assets of the respective entities.
	The Company’s loan agreements in the U.S., France and the Philippines 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 $88,684,000 and $148,467,000 at December 31, 2014, and 2013, respectively.
	Debt at December 31, 2014, matures as follows: $27,034,000 in 2015; $12,723,000 in 2016; $21,405,000 in 2017; $21,406,000 in 2018; $49,977,000 in 2019 and $141,386,000 after 2019. Debt maturing in 2015 includes $12,808,000 of scheduled repayments under long-term debt agreements and $14,226,000 of debt of foreign subsidiaries under short-term working capital loans. These short-term loan agreements are routinely renewed, but could be supplemented or replaced, if necessary, by the Company’s $125,000,000 revolving credit agreement.
	Net interest expense for the years ended December 31, 2014, 2013 and 2012, comprised the following:
	(In thousands)	2014			2013			2012
	Interest expense	$	12,542		$	11,104		$	9,998
	Interest income		(262	)		(57	)		(112	)
			12,280			11,047			9,886
	Capitalized interest		(839	)		(689	)		(287	)
	Interest expense, net	$	11,441		$	10,358		$	9,599

Leased_Properties

Leased Properties	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Leased Properties	7. Leased Properties
	The Company leases certain property and equipment (primarily transportation equipment, buildings and land) under operating leases, which are denominated in local currencies. Total rental expense was $6,660,000, $6,280,000 and $6,713,000 in 2014, 2013 and 2012, respectively.
	Consolidated Company minimum future rental payments under operating leases with terms in excess of one year as of December 31, 2014, are:
	(In thousands)	Year		Amount
			2015	$	4,523
			2016		3,522
			2017		2,163
			2018		1,866
			2019		1,822
			Subsequent to 2019		16,651
			Total minimum future rental payments	$	30,547

Other_Net

Other, Net	12 Months Ended
	Dec. 31, 2014
Other Income And Expenses [Abstract]
Other, Net	8. Other, Net
	Other, net in the consolidated statements of income included the following:
	(In thousands)	2014			2013			2012
	Foreign exchange loss	$	(220	)	$	(1,495	)	$	(304	)
	Investment related income		1,269			1,055			173
	Realized and unrealized gain on investments		241			2,611			1,460
	Other, net	$	1,290		$	2,171		$	1,329

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes
	The provisions for taxes on income and the related income before taxes for the years ended December 31, 2014, 2013 and 2012, were as follows:
	(In thousands)	2014			2013			2012
	Taxes on Income
	Federal
	Current	$	3,362		$	9,744		$	23,744
	Deferred		4,338			(285	)		(525	)
	State
	Current		782			1,223			1,999
	Deferred		643			(680	)		(537	)
	Foreign
	Current		9,004			12,067			10,158
	Deferred		325			1,224			1,196
	Total	$	18,454		$	23,293		$	36,035
	Income before Taxes
	Domestic	$	34,091		$	50,626		$	80,371
	Foreign		41,444			45,004			35,351
	Total	$	75,535		$	95,630		$	115,722
	The variations between the effective and statutory U.S. federal income tax rates are summarized as follows:
	(In thousands)	2014			%			2013			%			2012			%
		Amount						Amount						Amount
	Federal income tax provision at statutory tax rate	$	26,437			35		$	33,471			35		$	40,503			35
	State tax provision on income less applicable federal tax benefit		926			1.2			353			0.4			1,470			1.3
	Foreign income taxed at different rates		(5,175	)		(6.9	)		(2,509	)		(2.6	)		(1,172	)		(1.0	)
	Repatriation of foreign earnings		83			0.1			146			0.2			24			—
	Domestic production activities deduction		(312	)		(0.4	)		(991	)		(1.0	)		(1,446	)		(1.2	)
	Nontaxable foreign interest income		(2,435	)		(3.2	)		(2,614	)		(2.7	)		(2,690	)		(2.3	)
	Nontaxable biodiesel excise credit income		(130	)		(0.2	)		(2,347	)		(2.5	)		—			—
	U.S. tax credits		(1,086	)		(1.4	)		(2,209	)		(2.3	)		—			—
	Non-deductible expenses and other items, net		146			0.2			(7	)		(0.1	)		(654	)		(0.7	)
	Total income tax provision	$	18,454			24.4		$	23,293			24.4		$	36,035			31.1
	At December 31, 2014 and 2013, the tax effects of significant temporary differences representing deferred tax assets and liabilities were as follows:
	(In thousands)	2014			2013
	Deferred Tax Liabilities:
	Depreciation	$	(63,104	)	$	(57,113	)
	Amortization of intangibles		—			(49	)
	Unrealized foreign exchange loss		(838	)		(910	)
	Other		(1,159	)		(823	)
		$	(65,101	)	$	(58,895	)
	Deferred Tax Assets:
	Pensions	$	18,775		$	5,640
	Deferred revenue		1,650			3,058
	Other accruals and reserves		13,230			12,061
	Inventories		1,957			1,158
	Legal and environmental accruals		9,505			6,594
	Deferred compensation		15,636			20,510
	Bad debt and rebate reserves		4,618			3,018
	Subsidiaries net operating loss carryforwards		727			899
	Tax credit carryforwards		2,064			915
		$	68,162		$	53,853
	Valuation Allowance	$	(1,506	)	$	(1,302	)
	Net Deferred Tax (Liabilities) Assets	$	1,555		$	(6,344	)
	Reconciliation to Consolidated Balance Sheet:
	Current deferred tax assets	$	15,364		$	12,637
	Non-current deferred tax assets (in other non-current assets)		2,044			1,658
	Current deferred tax liabilities (in accrued liabilities)		(49	)		(23	)
	Non-current deferred tax liabilities		(15,804	)		(20,616	)
	Net Deferred Tax (Liabilities) Assets	$	1,555		$	(6,344	)
	Undistributed earnings of foreign subsidiaries and related companies that are deemed to be permanently reinvested amounted to $224,483,000 at December 31, 2014, compared to $194,148,000 at December 31, 2013. In general, the Company reinvests earnings of foreign subsidiaries in their operations indefinitely. However, the Company will repatriate earnings from a subsidiary where excess cash has accumulated and it is advantageous for tax or foreign exchange reasons. Because of the probable availability of foreign tax credits, it is not practicable to estimate the amount, if any, of the deferred tax liability on earnings reinvested indefinitely.
	The Company has tax loss carryforwards of $2,776,000 (pretax) as of December 31, 2014, and $3,980,000 as of December 31, 2013, that are available for use by the Company between 2015 and 2023. The Company has tax credit carryforwards of $2,064,000 as of December 31, 2014 and $915,000 as of December 31, 2013, that are available for use by the Company between 2015 and 2034.
	At December 31, 2014, the Company had valuation allowances of $1,506,000, which were primarily attributable to deferred tax assets in China, India and the Philippines. The realization of deferred tax assets is dependent on the generation of sufficient taxable income in the appropriate tax jurisdictions. The Company believes that it is more likely than not that the related deferred tax assets will not be realized.
	As of December 31, 2014 and 2013, unrecognized tax benefits totaled $464,000 and $240,000, respectively. The amount of unrecognized tax benefits that, if recognized, would favorably affect the Company’s effective income tax rate in any future periods, net of the federal benefit on state issues, was approximately $454,000, $231,000 and $275,000 at December 31, 2014, 2013 and 2012, respectively. The Company does not believe that the amount of unrecognized tax benefits related to its current uncertain tax positions will change significantly over the next 12 months.
	The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. In 2014, the Company recognized net interest and penalty expense of $6,000 compared to $9,000 and $444,000 of net interest and penalty income in 2013 and 2012, respectively. At December 31, 2014 the liability for interest and penalties was $38,000 compared to $32,000 at December 31, 2013.
	During 2012, the Company negotiated and finalized ten state income tax voluntary disclosure agreements. As a result, the Company recorded a net tax benefit of $688,000.
The Company files income tax returns in the U.S. federal jurisdiction and various states and foreign jurisdictions. The Company is not subject to U.S. federal income tax examinations by tax authorities for years before 2010. Some foreign jurisdictions and various U.S. states jurisdictions may be subject to examination back to 2008.
Below are reconciliations of the January 1 and December 31 balances of unrecognized tax benefits for 2014, 2013 and 2012:
(In thousands)	2014			2013			2012
Unrecognized tax benefits, opening balance	$	240		$	289		$	1,232
Gross increases – tax positions in prior period		—			27			—
Gross decreases – tax positions in prior period		—			(41	)		(569	)
Gross increases – current period tax positions		261			17			44
Settlements		—			—			—
Foreign currency translation		(13	)		5			23
Lapse of statute of limitations		(24	)		(57	)		(441	)
Unrecognized tax benefits, ending balance	$	464		$	240		$	289

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity
	On June 12, 2013, the Company announced that on August 9, 2013 (redemption date), it would redeem any remaining outstanding shares of its 5½ percent Convertible Preferred Stock without par value (preferred stock). At the time of the redemption announcement, there were 61,735 shares of preferred stock outstanding. Prior to the redemption date, preferred shareholders converted 60,900 shares of preferred stock into 139,029 shares of Company common stock. In accordance with the Certificate of Designation, Preferences and Rights of the 5 1/2% Convertible Preferred Stock, the Company redeemed 835 unconverted shares of Company preferred stock for an aggregate redemption price of $25.26354 per share ($25.00 per share plus accrued and unpaid dividends of $0.26354 per share). As of the redemption date, there are no longer any issued and outstanding shares of preferred stock.
	At December 31, 2014 and 2013, treasury stock consisted of 3,384,443 shares and 3,231,289 shares of common stock, respectively. During 2014, 154,633 shares of Company common stock were purchased in the open market, and 2,179 shares were received to settle employees’ minimum statutory withholding taxes related to performance stock awards and deferred compensation distribution. Also, 3,658 shares of treasury stock were distributed to participants as part of Company’s deferred compensation plan.

Stockbased_Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	11. Stock-based Compensation
	On December 31, 2014, the Company had stock options outstanding under its 2000 Stock Option Plan (2000 Plan), stock options and stock awards outstanding under its 2006 Incentive Compensation Plan (2006 Plan) and stock options, stock awards and SARs under its 2011 Incentive Compensation Plan (2011 Plan). Stock options, stock awards and SARs are currently granted to Company executives and other key employees. No further options or awards may be granted under the 2000 and 2006 Plans. The 2011 Plan authorized the award of 2,600,000 shares of the Company’s common stock for stock options, SARs and stock awards. At December 31, 2014, there were 1,971,353 shares available for grant under the 2011 Plan.
	Compensation expense (income) recorded in the consolidated statements of income for all plans was ($69,000), $2,783,000 and $3,122,000 for the years ended December 31, 2014, 2013 and 2012, respectively. The decline in stock-based compensation expense for the year ended December 31, 2014, compared to the year ended December 31, 2013, reflected adjustments to both performance stock awards and SARs. During the year, management adjusted the profitability estimates on which the compensation expenses for stock awards vesting on December 31, 2015 and 2016 were based, thereby reducing the number of shares expected to vest, which resulted in life-to-date adjustments to compensation expenses for those awards. In addition, due to a decrease in the market value of Company common stock, the fair value of SARs at December 31, 2014, declined, resulting in a reduction of the Company’s SARs liability that led to reversing compensation expense recorded in prior periods.
	The total income tax benefit (expense) recognized in the income statement for share-based compensation arrangements was ($26,000), $1,059,000 and $1,186,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
	Stock Options
	Under all plans, stock option awards are granted with an exercise price equal to the market price of the Company’s stock at the date of grant. The market price is defined and calculated as the average of the opening and closing prices for Company common stock on the grant date as reported in the New York Stock Exchange – Composite Transactions. The stock option awards generally vest based on two years of continuous service and have 8- to 10-year contractual terms. The fair value of each option award was estimated on the date of grant using the Black-Scholes option valuation model incorporating the weighted-average assumptions noted in the following table. Expected volatility is based on the historical volatility of the Company’s stock. The Company also uses historical data to estimate the expected term of options granted. The risk-free rate is the U.S. Treasury note rate that corresponds to the expected option term at the date of grant.
		For the Years Ended December 31
		2014		2013	2012
	Expected dividend yield	1.77%		2.01%	2.10%
	Expected volatility	42.04%		42.48%	43.19%
	Expected term	7.3 years		7.4 years	7.4 years
	Risk-free interest rate	2.18%		1.53%	1.41%
	A summary of stock option activity for the year ended December 31, 2014 is presented below:
		Shares			Weighted-		Weighted-		Aggregate
					Average		Average		Intrinsic Value
					Exercise Price		Remaining		$0
							Contractual
							Term
	Options
	Outstanding at January 1, 2014		505,112		$	30.8
	Granted		53,175			61.69
	Exercised		-67,029			26.17
	Forfeited		-10,522			54.41
	Outstanding at December 31, 2014		480,736			34.35		4.43	$	2,757
	Vested or expected to vest at December 31, 2014		480,736			34.35		4.43		2,757
	Exercisable at December 31, 2014		384,457			27.37		3.37		4,885
	The weighted-average grant-date fair values of options awarded during the years ended December 31, 2014, 2013 and 2012, were $23.77, $23.08 and $15.73, respectively. The total intrinsic values of options exercised during the years ended December 31, 2014, 2013, and 2012 were $2,071,000, $9,138,000, and $17,163,000, respectively.
	As of December 31, 2014, the total unrecognized compensation cost for unvested stock options was $774,000.  That cost is expected to be recognized over a weighted-average period of 1.0 years.
	Cash received from stock option exercises under the Company’s stock option plans for the years ended December 31, 2014, 2013, and 2012 was $1,754,000, $3,977,000 and $4,473,000, respectively. The actual tax benefit realized for the tax deductions from stock option exercises totaled $568,000, $2,786,000, and $6,411,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
	Stock Awards
	In 2012, 2013, and 2014, the Company granted stock awards under the 2006 and 2011 Plans. The stock awards vest only upon the Company’s achievement of certain levels of consolidated net income and return on invested capital by the end of the specified measurement periods, which are December 31, 2014, 2015 and 2016 for the 2012, 2013 and 2014 awards, respectively. The number of Company shares of common stock ultimately distributed, if any, is contingent upon the level of consolidated net income and return on invested capital attained. The fair value of stock awards equals the grant-date market price of the Company’s common stock, discounted for the estimated amount of dividends that would not be received during the measurement period. Compensation expense is recorded each reporting period based on the probable number of awards that will ultimately vest given the projected level of consolidated net income and return on invested capital. If at the end of the measurement period the performance objectives are not met, no compensation cost is recognized and any compensation expense recorded in prior periods is reversed.   No performance stock awards vested for the measurement period ended December 31, 2014, because the financial performance conditions for those awards were not met.
	A summary of stock award activity for the year ended December 31, 2014, is presented below:
		Shares			Weighted-Average Grant
					Date
					Fair Value
	Unvested Stock Awards
	Unvested at January 1, 2014		221,090		$	48.75
	Granted		89,234			59.52
	Vested		—			—
	Forfeited		127,314			43.12
	Unvested at December 31, 2014		183,010			57.92
	The weighted-average grant-date fair values of stock awards granted during the years ended December 31, 2014, 2013 and 2012, were $59.52, $60.75 and $41.00, respectively. As of December 31, 2014, under the current Company assumption as to the number of stock award shares that will probably vest at the measurement periods ended December 31, 2015 and 2016, there was $1,365,000 of unrecognized compensation cost for unvested stock awards. That cost is expected to be recognized over a period of 2.0 years.
	In general, it is the Company’s policy to issue new shares of its common stock upon the exercise of stock options or the vesting of stock awards.
	SARs
	SARs cliff vest after two years of continuous service, settle in cash and expire ten years from the grant date. Upon the exercise of a SARs award, a participant receives in cash an amount that equals the excess of the fair market value of a share of Company common stock at the date of exercise over the fair market value of a share of Company common stock at the date of grant (the exercise price). Because SARs are cash-settled, they are accounted for as liabilities that must be re-measured at fair value at the end of every reporting period until settlement. Compensation expense for each reporting period is based on the period-to-period change (or portion of the change, depending on the proportion of the vesting period that has been completed at the reporting date) in the fair value of the SARs.
	A summary of SARs activity for the year ended December 31, 2014 is presented below:
		Shares			Weighted-		Weighted-		Aggregate
					Average		Average		Intrinsic Value
					Exercise Price		Remaining		$0
							Contractual
							Term
	SARs
	Outstanding at January 1, 2014		148,311		$	54.6
	Granted		116,843			61.62
	Forfeited		(33,972	)		55.99
	Outstanding at December 31, 2014		231,182			57.94		8.4	$	(4,130	)
	The weighted-average grant-date fair values of SARs granted during the years 2014, 2013 and 2012 were $23.74, $23.12 and $15.73, respectively. The fair value for each SARs award was estimated using the Black-Scholes valuation model incorporating the same assumptions as noted for stock options.
	As of December 31, 2014 and 2013, the SARs liability recorded on the consolidated balance sheet (non-current liabilities) was $1,457,000 and $2,172,000, respectively. In addition, at December 31, 2014, there was $693,000 of total unrecognized compensation cost related to unvested SARs. That cost is to be recognized over a weighted-average period of 1.1 years.

Deferred_Compensation

Deferred Compensation	12 Months Ended
	Dec. 31, 2014
Compensation Related Costs [Abstract]
Deferred Compensation	12. Deferred Compensation
	The Company sponsors deferred compensation plans that allow management employees to defer receipt of their annual bonuses and outside directors to defer receipt of their fees until retirement, departure from the Company or as elected. Compensation expense and the related deferred compensation obligation are recorded when the underlying compensation is earned. Over time, the deferred obligation may increase or decrease based on the performance results of investment options chosen by the plan participants. The investment options include Company common stock and a limited selection of mutual funds. The Company maintains sufficient shares of treasury stock to cover the equivalent number of shares that result from participants elections of the Company common stock investment option. As a result, the Company must periodically purchase its common shares in the open market. The Company purchases shares of the applicable mutual funds to fund the portion of its deferred compensation liabilities tied to such investments.
	Some plan distributions may be made in cash or Company common stock at the option of the participant. Other plan distributions can only be made in Company common stock. For deferred compensation obligations that may be settled in cash or Company common stock at the option of the participant, the Company must record appreciation in the market value of the investment choices made by participants as additional compensation expense. Conversely, declines in the market value of the investment choices reduce compensation expense. Increases and decreases of compensation expense that result from fluctuations in the underlying investments are recorded in the administrative expense line of the consolidated statements of income. The additional compensation income or expense resulting from the changes in the market values and earnings of the selected investment options was $11,903,000 income in 2014, $9,496,000 expense in 2013 and $10,252,000 expense in 2012. The 2014 income primarily resulted from a current year decline in the value of Company common stock. The obligations that must be settled only in Company common stock are treated as equity instruments; therefore, fluctuations in the market price of the underlying Company stock do not affect earnings. The Company’s deferred compensation liability was $38,730,000 and $51,543,000 at December 31, 2014 and 2013, respectively.

Postretirement_Benefit_Plans

Postretirement Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation And Retirement Disclosure [Abstract]
Postretirement Benefit Plans	13. Postretirement Benefit Plans
	Defined Benefit 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 various U.S. defined benefit pension plans were amended in 2005-2008 to freeze the plans by stopping the accrual of service benefits. The U.K. defined benefit pension plan was frozen in 2006. Benefits earned through the freeze dates are available to participants when they retire, in accordance with the terms of the plans. In addition, the Company established defined contribution plans to replace the frozen defined benefit pension plans.
	Obligations and Funded Status at December 31
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Change in benefit obligation
	Benefit obligation at beginning of year	$	144,508		$	157,051		$	21,095		$	21,722
	Interest cost		6,936			6,424			964			899
	Actuarial (gain) loss		23,547			(14,142	)		3,176			(1,365	)
	Benefits paid		(5,584	)		(4,825	)		(822	)		(521	)
	Foreign exchange impact		—			—			(1,430	)		360
	Benefit obligation at end of year	$	169,407		$	144,508		$	22,983		$	21,095
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Change in plan assets
	Fair value of plan assets at beginning of year	$	133,264		$	124,682		$	22,204		$	18,390
	Actual return on plan assets		(2,929	)		13,225			1,902			2,840
	Employer contributions		1,618			182			1,004			949
	Benefits paid		(5,584	)		(4,825	)		(822	)		(521	)
	Foreign exchange impact		—			—			(1,430	)		546
	Fair value of plan assets at end of year	$	126,369		$	133,264		$	22,858		$	22,204
	Over (Under) funded status at end of year	$	(43,038	)	$	(11,244	)	$	(125	)	$	1,109
	The amounts recognized in the consolidated balance sheets at December 31 consisted of
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Non-current asset	$	—		$	818		$	—		$	1,109
	Current liability		(185	)		(185	)		—			—
	Non-current liability		(42,853	)		(11,877	)		(125	)		—
	Net amount recognized	$	(43,038	)	$	(11,244	)	$	(125	)	$	1,109
	The amounts recognized in accumulated other comprehensive income at December 31 consisted of
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Net actuarial loss	$	60,114		$	26,802		$	4,724		$	2,147
	The accumulated benefit obligations at December 31, 2014, for the U.S. and U.K. defined benefit plans were $169,407,000 and $22,983,000, respectively. Below is information for pension plans with projected benefit obligations in excess of plan assets at December 31:
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Projected benefit obligation	$	169,407		$	113,865		$	22,983		$	—
	Accumulated benefit obligation		169,407			113,865			22,983			—
	Fair value of plan assets		126,369			101,803			22,858			—
	Components of Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income
	Net periodic benefit costs for the years ended December 31, 2014, 2013 and 2012, were as follows:
	(In thousands)	United States									United Kingdom
		2014			2013			2012			2014			2013			2012
	Interest cost	$	6,936		$	6,424		$	6,880		$	964		$	899		$	841
	Expected return on plan assets		(9,523	)		(8,828	)		(8,423	)		(1,303	)		(941	)		(888	)
	Amortization of net actuarial loss		2,687			5,109			3,573			—			288			49
	Net periodic benefit cost	$	100		$	2,705		$	2,030		$	(339	)	$	246		$	2
	Other changes in plan assets and benefit obligations recognized in other comprehensive income for the years ended December 31, 2014, 2013 and 2012, were as follows:
	(In thousands)	United States									United Kingdom
		2014			2013			2012			2014			2013			2012
	Net actuarial (gain) loss	$	35,999		$	(18,539	)	$	4,622		$	2,577		$	(3,264	)	$	3,111
	Amortization of net actuarial loss		(2,687	)		(5,109	)		(3,573	)		—			(288	)		(49	)
	Total recognized in other comprehensive income	$	33,312		$	(23,648	)	$	1,049		$	2,577		$	(3,552	)	$	3,062
	Total recognized in net periodic benefit cost and other comprehensive income	$	33,412		$	(20,943	)	$	3,079		$	2,238		$	(3,306	)	$	3,064
	The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2015 are as follows:
	(In thousands)	United States			United Kingdom
	Net actuarial loss	$	4,597		$	184
	Estimated Future Benefit Payments
	(In thousands)	United States			United Kingdom
	2015	$	6,153		$	558
	2016		6,714			584
	2017		7,322			620
	2018		7,821			631
2019		8,283			639
2020-2024		48,207			3,721
Assumptions
The weighted-average assumptions used to determine benefit obligations at December 31 were as follows:
	United States						United Kingdom
	2014			2013			2014			2013
Discount rate		4.09	%		4.87	%		3.5	%		4.6	%
With respect to the assumptions used to determine benefit obligations at December 31, 2014, the Company also adopted the most recent mortality table (RP-2014) issued by the Society of Actuaries. This change in mortality assumptions increased the Company’s benefit obligation by approximately $9,500,000.
The weighted-average assumptions used to determine net periodic benefit costs for years ended December 31 were as follows:
	United States									United Kingdom
	2014			2013			2012			2014			2013			2012
Discount rate		4.87	%		4.17	%		5.06	%		4.6	%		4.3	%		4.9	%
Expected long-term return on plan assets		7.75	%		7.75	%		7.75	%		5.84	%		5.25	%		5.46	%
In addition to the above assumptions, the Company uses a market-related value of assets approach to calculate the expected return on plan assets component of U.S. net periodic benefit cost. The market-related value equals the fair value of plan assets with five-year smoothing of asset gains or losses. Asset gains are subtracted or losses added in the following way: 80 percent of the prior year’s gain or loss; 60 percent of the second preceding year’s gain or loss; 40 percent of the third preceding year’s gain or loss; and 20 percent of the fourth preceding year’s gain or loss. Gains or losses for the year are calculated as the difference between the expected fair value of assets and the actual fair value of assets.
Investment Strategies and Policies
U.S. Plans
Plan assets are predominantly invested using active investment strategies, as compared to passive or index investing. An investment management firm hires and monitors underlying investment management firms for each asset category. Equity managers within each category cover a range of investment styles and approaches, including both active and passive, and are combined in a way that controls for capitalization, style biases, and country exposure versus benchmark indexes, while active managers focus primarily on stock selection to improve returns. Fixed income managers seek to reduce the volatility of the plan’s funded status by matching the duration with the plan’s liability while seeking to improve returns through security selection, sector allocation and yield curve management. Real estate uses public core real estate strategies, which provide stable and high levels of current income and enhanced core strategies, which seek slightly higher returns by emphasizing appreciation. Commodity managers are used to further diversify the portfolio and may serve as an inflation hedge and are benchmarked to a diversified commodities index.
Risk is controlled through diversification among multiple asset categories, managers, styles, and securities. The investment management firm recommends asset allocations based on the time horizon available for investment, the nature of the plan cash flows and liabilities and other factors that affect risk tolerance. The asset allocation targets are approved by the Company’s Plan Committee. Risk is further controlled both at the manager and asset category level by assigning targets for risk versus investment returns.
Allowable investment categories include:
Equities: Common stocks of large, medium, and small companies, including both U.S. and non-U.S. based companies. The long-term target allocation for equities, excluding Company stock, is 34 percent.
Fixed Income (Debt): Bonds or notes issued or guaranteed by the U.S. government, and to a lesser extent, by non-U.S. governments, or by their agencies or branches, mortgage-backed securities, including collateralized mortgage obligations, corporate bonds, municipal bonds and dollar-denominated debt securities issued in the U.S. by non-U.S. banks and corporations. Up to 20 percent of the fixed income assets may be in debt securities that are below investment grade. The target allocation for fixed income is 35 percent.
Real Estate: Public real estate funds using office, apartment, industrial, retail, and other property types. The target allocation for real estate is 4 percent.
Commodities: Commodity funds that match the index using commodity-linked derivative instruments including swap agreements, commodity options, futures, options on futures and commodity-linked notes, while seeking to enhance overall returns through the use of fixed income securities. The target allocation for commodities is 2 percent.
Employer Securities: The retirement plans also hold shares of the Company’s common stock, which are purchased or sold by the trustee from time to time, as directed by the Plan Committee. At the direction of the Plan Committee, the plans sold 37,999 common shares to the Company’s ESOP trust on February 19, 2014, and 43,534 common shares on February 20, 2013. The target allocation for employer securities is 25 percent.
In addition to these primary investment types, excess cash may be invested in futures in order to efficiently achieve more fully invested portfolio positions. Otherwise, a small number of investment managers make limited use of derivatives, including futures contracts, options on futures and interest rate swaps in place of direct investment in securities to efficiently achieve equivalent market positions. Derivatives are not used to leverage portfolios.
U.K. Plan
The objective of the U.K. defined benefit pension fund investment strategy is to maximize the long-term rate of return on plan assets within a medium level of risk in order to minimize the cost of providing pension benefits. To that end, the plan assets are invested in an actively managed pooled fund of funds that diversifies its holdings among equity securities, debt securities, property and cash. Essentially, the plan is to hold equity instruments to back the benefits of participants yet to retire and bonds and cash to back current pensioners. Although there are no formal target allocations for the plan assets, the fund will generally be heavily invested in equity securities. Equity securities are selected from U.K., European, U.S. and emerging market companies. Bonds include U.K. and other countries’ government notes and corporate debt of U.K and non-U.K. companies. There are no specific prohibited investments, but the current managed fund will not allocate assets to derivatives or other financial hedging instruments. Plan trustees meet regularly with the fund manager to assess the fund’s performance and to reassess investment strategy.
At December 31, 2014, equities within the pooled pension fund comprised 23 percent U.K. companies, 41 percent U.S. companies, 20 percent other European companies and 16 percent companies from other regions of the world. The equities are spread across growth and value styles. Fixed income instruments primarily included U.K. bonds, mainly government fixed interest securities with short to mid-tem maturities. Fixed income instruments also included government fixed instrument securities of geographic areas other than the U.K.
Included in plan assets are insurance contracts purchased by the plan trustees to provide pension payments for specific retirees. In past years, at the time a plan participant retired, the plan trustee would periodically purchase insurance contracts to cover the future payments due the retiree. This practice is no longer followed. The contracts are revocable, and the related plan obligations are not considered settled. Therefore, the plan assets and obligations include the insured amounts.
Plan Assets
U.S. Plans
The Company’s asset allocations for its U.S. pension plans at December 31, 2014 and 2013, by asset category, were as follows:
	December 31, 2014
(In thousands)	Level 1			Level 2			Level 3			Total
Cash and Cash Equivalents	$	—		$	1,963		$	—		$	1,963
Equity Securities
U.S. Equities		34,885			—			—			34,885
Non-U.S. Equities		12,478			—			—			12,478
Employer Securities		21,575			—			—			21,575
Total Equities		68,938			—			—			68,938
Fixed Income Securities
U.S. Corporate Bonds		—			27,676			—			27,676
U.S. Government and Agency Bonds		350			10,327			—			10,677
Municipal Bonds		—			3,352			—			3,352
Other Bonds		—			6,155			—			6,155
Total Fixed Income		350			47,510			—			47,860
Real Estate		5,585			—			—			5,585
Commodities		2,023			—			—			2,023
Total	$	76,896		$	49,473		$	—		$	126,369
	December 31, 2013
(In thousands)	Level 1			Level 2			Level 3			Total
Cash and Cash Equivalents	$	—		$	2,471		$	—		$	2,471
Equity Securities
U.S. Equities		32,567			—			—			32,567
Non-U.S. Equities		11,892			—			—			11,892
Employer Securities		37,823			—			—			37,823
Total Equities		82,282			—			—			82,282
Fixed Income Securities
U.S. Corporate Bonds		—			24,733			—			24,733
U.S. Government and Agency Bonds		2,526			6,575			—			9,101
Municipal Bonds		—			3,116			—			3,116
Other Bonds		—			4,559			—			4,559
Total Fixed Income		2,526			38,983			—			41,509
Real Estate		6,090			—			—			6,090
Commodities		912			—			—			912
Total	$	91,810		$	41,454		$	—		$	133,264
Plan Asset Valuation Methodology
Following is a description of the valuation methodologies used for plan assets measured at fair value.
Individual equity securities, including employer securities, are valued by Standard & Poor’s Securities Evaluations as determined by quoted market prices on the New York Stock Exchange or other active markets. Both market pricing and future cash flow analysis may be used in the pricing process as follows:
Level 1 – Equities represent the largest asset category and are valued according to the exchange-quoted market prices of the underlying investments. Level 1 fixed income securities are U.S. government securities and are valued according to quoted prices from active markets.
Level 2 – Fixed income investments without equivalent trading exchanges are valued primarily through a technique known as “future cash flow approach” which is based on what bondholders can reasonably expect to receive based upon an issuer’s current financial condition. Pricing analysts prepare cash-flow forecasts and utilize one or two pricing models to arrive at an evaluated price. Evaluated bid modeling includes factors such as the interest rate on the coupon, maturity, rating, cash flow projections and other factors.
Level 3 – no investments held during 2014 or 2013 are categorized as Level 3.
U.K. Plan
The Company’s asset allocations for its U.K. pension plans at December 31, 2014 and 2013, by asset category, were as follows:
	December 31, 2014
(In thousands)	Level 1			Level 2			Level 3			Total
Cash	$	1,176		$	—		$	—		$	1,176
Equity Securities
Pooled Pension Funds		—			15,322			—			15,322
Fixed Income
Pooled Pension Funds		—			3,642			—			3,642
Real Estate
Pooled Pension Funds		—			477			—			477
Insurance Contracts		—			—			2,241			2,241
Total	$	1,176		$	19,441		$	2,241		$	22,858
	December 31, 2013
(In thousands)	Level 1			Level 2			Level 3			Total
Cash	$	412		$	—		$	—		$	412
Equity Securities
Pooled Pension Funds		—			15,397			—			15,397
Fixed Income
Pooled Pension Funds		—			3,550			—			3,550
Real Estate
Pooled Pension Funds		—			419			—			419
Insurance Contracts		—			—			2,426			2,426
Total	$	412		$	19,366		$	2,426		$	22,204
Units of each of the pooled funds are valued by the trustee based on quoted market prices of the underlying investments (the underlying assets are either exchange traded or have readily available markets).
Fair value changes within asset categories for which fair value measurements use significant unobservable inputs (Level 3) were as follows during 2013 and 2014:
(In thousands)	Insurance Contracts
Fair value, December 31, 2012	$	2,437
Sale proceeds (benefit payments)		(175	)
Change in unrealized gain		120
Foreign exchange impact		44
Fair value, December 31, 2013	$	2,426
Sale proceeds (benefit payments)		(178	)
Change in unrealized gain		135
Foreign exchange impact		(142	)
Fair value, December 31, 2014	$	2,241
Long-term Rate of Return for Plan Assets
U.S. Plans
The overall expected long-term rate of return on assets of 7.75 percent that was used to develop the 2014 pension expense is based on plan asset allocation, capital markets forecasts and expected benefits of active investment management. For fixed income, the expected return is 4.73 percent. This assumption includes the yield on the five-year zero-coupon U.S. Treasury bond as the base rate along with historical data from the U.S. Treasury yield curve. For equities, the expected return is 8.82 percent for U.S. and international equities. This return is based on a blended average of three different statistical models that each incorporates multiple factors including, for example, inflation, Gross Domestic Product and the Fed Funds Target Rate. For real estate, the expected return is 7.40 percent. For commodities, the expected return is 6.70 percent.
The overall investment return forecast reflects the target allocations and the capital markets forecasts for each asset category, plus a premium for active asset management expected over the long-term.
U.K. Plan
The overall expected long-term return on plan assets is a weighted-average of the expected long-term returns for equity securities, debt securities and other assets. The redemption yield at the measurement date on U.K. government fixed interest bonds and the yield on corporate bonds are used as proxies for the return on the debt portfolio. The returns for equities and property are estimated as a premium of 3.0 percent added to the risk-free rate. Cash is assumed to have a long-term return of 4.0 percent.
Other Defined Benefit Plans
The Company maintains funded and unfunded defined benefit plans in other foreign locations. The liabilities and expenses associated with these plans, individually and collectively, are not material to the Company’s consolidated financial statements. Discount rates for these plans are determined based on local interest rates and plan participant data.
Cash Flows
As a result of pension funding relief included in the Highway and Transportation Funding act of 2014, the Company expects to make no 2015 contributions to the funded U.S. qualified defined benefit plans. $185,000 is expected to be paid related to the unfunded non-qualified U.S. pension plans.  The Company expects to contribute $950,000 to the U.K. defined benefit plan in 2015.
Defined Contribution Plans
The Company sponsors retirement savings defined contribution plans that cover U.S. and U.K. employees. The Company also sponsors a profit sharing plan for its U.S. employees. Profit sharing contributions are determined each year using a formula that is applied to Company earnings. The contributions, which are made partly in cash and partly in Company common stock, are allocated to participant accounts on the basis of participant base earnings. The retirement savings and profit sharing defined contribution plans each include a qualified plan and a non-qualified supplemental executive plan.
Defined contribution plan expenses for the Company’s retirement savings plans and profit sharing plan were as follows:
(In thousands)	2014			2013			2012
Retirement savings plans	$	4,565		$	4,500		$	4,284
Profit sharing plan		3,619			4,804			5,762
Total	$	8,184		$	9,304		$	10,046
In July 2011, the Company established a rabbi trust to fund the obligations of its previously unfunded 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 sheet. 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 income statement. The supplemental plan liabilities increase (i.e., supplemental plan expense is recognized) when the value of the trust assets appreciates and decrease (i.e., supplemental plan income is recognized) when the value of the trust assets declines. At December 31, 2014 and 2013, the trust asset balances were $1,741,000 and $1,849,000, respectively, and the supplemental plan liability balances were $1,776,000 and $1,899,000, respectively. The differences between the trust asset balances and the supplemental liability balances were due to estimated liabilities that were not funded until after the end of the year when the actual liabilities were determined.
In addition to the Company sponsored profit sharing plan, certain foreign locations are required by law to make profit sharing contributions to employees based on statutory formulas. For the years ended December 31, 2014, 2013 and 2012, the Company recognized $145,000, $1,999,000 and $711,000, respectively, of statutory profit sharing expense.

Accrued_Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2014
Payables And Accruals [Abstract]
Accrued Liabilities	14. Accrued Liabilities
	The composition of accrued liabilities was as follows:
		December 31
	(In thousands)	2014		2013
	Accrued payroll and benefits	$	28,060	$	39,722
	Accrued customer rebates		17,395		15,514
	Other accrued liabilities		20,041		21,103
	Total accrued liabilities	$	65,496	$	76,339

Other_NonCurrent_Liabilities

Other Non-Current Liabilities	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Other Non-Current Liabilities	15. Other Non-Current Liabilities
	The composition of other non-current liabilities was as follows:
		31-Dec
	(In thousands)	2014		2013
	Deferred revenue	$	3,318	$	4,045
	Environmental and legal matters		20,583		13,133
	Deferred compensation liability		37,790		50,728
	Pension liability		45,738		14,923
	Other non-current liabilities		5,427		5,777
	Total other non-current liabilities	$	112,856	$	88,606

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Contingencies	16. 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). Over the years, the Company has received requests for information related to or has been named by the government as a PRP at a number of waste disposal and manufacturing 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. The Company believes that it has made adequate provisions for the costs it may incur with respect to these sites.
	As of December 31, 2014, the Company estimated a range of possible environmental and legal losses of $21.9 million to $41.8 million. 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 $22.0 million at December 31, 2014, compared to $14.7 million at December 31, 2013. The increase in the environmental and legal liability was primarily attributable to a $7.1 million increase in the estimate to remediate the Company’s Maywood, New Jersey site.  See the Maywood, New Jersey section of this footnote for further information.  During 2014, cash outlays related to legal and environmental matters approximated $1.2 million compared to $2.4 million in 2013.
	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. 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. 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.
	Following are summaries of the material contingencies at December 31, 2014:
	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 1993 pursuant to the provisions of CERCLA because of certain alleged chemical contamination. Pursuant to an Administrative Order on Consent entered into between 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 (RI/FS) and has recorded a liability based on its best estimate of the remediation costs.
	On September 24, 2014, USEPA issued its Record of Decision (“ROD”) for chemically-contaminated soil. In addition, USEPA issued a Notice of Potential Liability letter (“Notice”) dated September 30, 2014. The Company has responded to the Notice indicating a willingness to meet and discuss these matters with USEPA. Based on its current review and analysis of the ROD and subsequent discussions with USEPA, the Company has increased its recorded liability for claims associated with soil remediation of chemical contamination by $7.1 million and believes such increase represents its best estimate of the cost of remediation for the Maywood site. The Company’s best estimate of the cost of remediation for the Maywood site could change as it continues to discuss these matters with USEPA and the design of the remedial action progresses. Depending on the ultimate cost of this remediation, the amount for which the Company is liable could differ from the Company’s current recorded liability.
	In addition, under the terms of a settlement agreement reached on November 12, 2004, the United States 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 potentially responsible party (PRP) in the case United States v. Lightman (1:92-cv-4710 D.N.J.), which involved the D’Imperio Property Site located in New Jersey. In 2012, the PRPs approved certain changes to 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 for claims associated with the D’Imperio site is adequate. However, actual costs could differ from current estimates.
	Wilmington Site
	The Company is currently contractually obligated to contribute to the response costs associated with the Company’s formerly-owned site at 51 Eames Street, 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. To date, the Company has paid the current owner $2.3 million for the Company’s portion of environmental response costs through the third quarter of 2014 (the current owner of the site bills the Company one calendar quarter in arrears). 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.
	The Company believes that based on current information it has adequate reserves for the claims related to this site. However, 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.
	Unclaimed Property Examination
	The Company is undergoing an unclaimed property examination by the state of Delaware (the Company’s state of incorporation) and seven other states for the period covering 1981 through 2010. The types of unclaimed property under examination include certain un-cashed payroll and accounts payable checks and certain accounts receivable credits. Generally, unclaimed property must be reported and remitted to the state of the rightful owner. In cases where the rightful owner cannot be identified, the property must be reported and remitted to the unclaimed property holder’s state of incorporation. The examination of un-cashed payroll and accounts payable checks has been completed, and no significant adjustments to the Company’s unclaimed property liability were required. The examination of accounts receivable credits is ongoing, and on the basis of currently available information, the Company increased its liability for unclaimed property in the fourth quarter of 2014. The adjustment was not material to the Company’s results of operations. Because the audit is not final, the Company’s ultimate actual obligation could differ from the recorded liability.
	Customer Claims
	From time to time in the normal course of business, customers make claims against the Company for issues such as product performance and liability, contract disputes, delivery errors and other various concerns. Frequently, such claims are subject to extensive investigation, discussion and negotiation prior to settlement or resolution. In the fourth quarter of 2014, the Company recognized $3,475,000 of expense for customer claims. The expense recognized was based on the best and most current information available to management. However, investigations and discussions with the affected customers are ongoing. Therefore, the actual amounts paid, if any, to settle the claims could differ significantly from the amounts currently recorded.

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Reporting	17. Segment Reporting
	The Company has three reportable segments: Surfactants, Polymers and Specialty Products. Each segment provides distinct products and requires separate management due to unique markets, technologies and production processes. Surfactants are used in a variety of consumer and industrial cleaning compounds as well as in agricultural products, lubricating ingredients, oil field chemicals and other specialized applications. Polymers are used primarily in plastics, building materials, refrigeration systems and CASE applications. Specialty Products are used in food, flavoring, nutritional supplement and pharmaceutical applications.
	The Company evaluates the performance of its segments and allocates resources based on operating income before interest expense, other income/expense items and income tax provision. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies.
	Segment data for the three years ended December 31, 2014, 2013 and 2012, are as follows:
	(In thousands)		Surfactants			Polymers			Specialty			Segment
									Products			Totals
	2014
	Net sales		$	1,296,638		$	550,966		$	79,609		$	1,927,213
	Operating income			60,778			60,690			10,487			131,955
	Assets			741,677			320,640			67,588			1,129,905
	Capital expenditures			70,796			22,409			5,618			98,823
	Depreciation and			41,483			18,433			2,792			62,708
	amortization expenses
	2013
	Net sales		$	1,317,164		$	483,361		$	80,261		$	1,880,786
	Operating income			100,201			54,536			10,902			165,639
	Assets			710,521			292,015			68,413			1,070,949
	Capital expenditures			66,266			18,804			6,370			91,440
	Depreciation and			36,400			16,351			2,631			55,382
	amortization expenses
	2012
	Net sales		$	1,305,800		$	423,959		$	73,978		$	1,803,737
	Operating income			118,591			48,130			12,242			178,963
	Assets			692,891			199,013			58,810			950,714
	Capital expenditures			56,236			19,266			5,815			81,317
	Depreciation and			34,036			13,328			2,270			49,634
	amortization expenses
	Below are reconciliations of segment data to the consolidated financial statements:
	(In thousands)		2014			2013			2012
	Operating income - segment totals		$	131,955		$	165,639		$	178,963
	Business restructuring and asset impairments (a)			(4,009	)		(1,040	)		—
	Unallocated corporate expenses (b)			(37,252	)		(55,446	)		(50,247	)
	Total operating income			90,694			109,153			128,716
	Interest expense, net			(11,441	)		(10,358	)		(9,599	)
	Loss from equity in joint ventures			(5,008	)		(5,336	)		(4,724	)
	Other, net			1,290			2,171			1,329
	Consolidated income before income taxes		$	75,535		$	95,630		$	115,722
	Assets - segment totals		$	1,129,905		$	1,070,949		$	950,714
	Unallocated corporate assets (c)			32,109			96,253			34,764
	Consolidated assets		$	1,162,014		$	1,167,202		$	985,478
	Capital expenditures - segment totals		$	98,823		$	91,440		$	81,317
	Unallocated corporate expenditures			2,996			1,425			1,842
	Consolidated capital expenditures		$	101,819		$	92,865		$	83,159
	Depreciation and amortization expenses – segment totals		$	62,708		$	55,382		$	49,634
	Unallocated corporate depreciation expenses			1,096			1,018			1,660
	Consolidated depreciation and amortization expenses		$	63,804		$	56,400		$	51,294
	(a)	See Note 21 regarding business restructuring and asset impairment costs.
	(b)	Unallocated corporate expenses primarily comprise 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.
	(c)	The decline in unallocated corporate assets between 2013 and 2014 was primarily attributable to decreases in the balances of U.S. cash and cash equivalents, which are not allocated to segments. The increase in unallocated corporate assets between 2012 and 2013 was primarily attributable to increases in the balances of U.S. cash and cash equivalents and mutual fund investment assets, which are not allocated to segments.
	Below is certain Company-wide geographic data for the years ended December 31, 2014, 2013 and 2012:
	(In thousands)		2014			2013			2012
	Net sales (a)
	United States		$	1,146,405		$	1,103,181		$	1,076,222
	France (b)			183,896			221,971			298,158
	Poland (b)			175,862			122,215			19,588
	United Kingdom			103,696			104,470			103,523
	All other countries			317,354			328,949			306,246
	Total		$	1,927,213		$	1,880,786		$	1,803,737
	Long-lived assets (c)
	United States		$	360,921		$	330,799		$	246,118
	Germany			36,156			42,309			34,213
	Singapore			41,909			44,315			43,239
	Philippines			17,793			18,817			22,658
	Brazil			25,991			22,920			18,410
United Kingdom			23,040			23,061			20,878
All other countries			50,690			47,216			52,483
Total		$	556,500		$	529,437		$	437,999
(a)	Net sales are attributed to countries based on selling location.
(b)	The 2012-to-2013 net sales increase for Poland and net sales decrease for France reflected the 2013 transfer of ownership of the Company’s European Polymer intangibles from the Company’s France subsidiary to its Poland subsidiary, which resulted in European Polymer sales being recognized in Poland instead of France.
(c)	Includes net property, plant and equipment, goodwill and other intangible assets.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share	18. Earnings Per Share
	Below is the computation of basic and diluted earnings per share for the years ended December 31, 2014, 2013 and 2012:
	(In thousands, except per share amounts)		2014		2013		2012
	Computation of Basic Earnings per Share
	Net income attributable to Stepan Company		$	57,101	$	72,828	$	79,396
	Deduct dividends on preferred stock			—		43		579
	Income applicable to common stock		$	57,101	$	72,785	$	78,817
	Weighted-average number of shares outstanding			22,758		22,621		21,273
	Basic earnings per share		$	2.51	$	3.22	$	3.71
	Computation of Diluted Earnings per Share
	Net income attributable to Stepan Company		$	57,101	$	72,828	$	79,396
	Weighted-average number of shares outstanding			22,758		22,621		21,273
	Add weighted-average net shares from assumed exercise of options (under treasury stock			148		215		392
	method) (1)
	Add weighted-average contingently issuable net shares related to performance stock awards (under treasury stock method)			─		─		12
	Add weighted-average unvested stock awards (under treasury stock method)			11		8		6
	Add weighted-average shares from assumed conversion of convertible preferred stock			─		80		1,047
	Weighted-average shares applicable to diluted			22,917		22,924		22,730
	earnings
	Diluted earnings per share		$	2.49	$	3.18	$	3.49
	-1	Options to purchase 99,044, 49,815 and 16,444 shares of common stock were not included in the computations of diluted earnings per share for the years ended December 31, 2014, 2013 and 2012, respectively. The options’ exercise prices were greater than the average market price for the common stock and the effect of the options on earnings per share would have been antidilutive.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	19. Accumulated Other Comprehensive Income (Loss)
	Below is the change in the Company’s accumulated other comprehensive income (loss) (AOCI) balance by component (net of income taxes) for the years ended December 31, 2012, 2013 and 2014:
	(In thousands)		Foreign			Defined
			Currency			Benefit			Cash Flow
			Translation			Pension Plan			Hedge
			Adjustments			Adjustments			Adjustments			Total
	Balance at December 31, 2011		$	(9,086	)	$	-32,398		$	(1	)	$	(41,485	)
	Other comprehensive income before							)
	reclassifications			6,200			(5,387			116			929
	Amounts reclassified from AOCI			—			2,287			19			2,306
	Net current period other comprehensive income							)
				6,200			(3,100			135			3,235
	Balance at December 31, 2012		$	(2,886	)	$	(35,498	)	$	134		$	(38,250	)
	Other comprehensive income before				)						)
	reclassifications			(8,085			13,417			(32			5,300
	Amounts reclassified from AOCI			—			3,409			13			3,422
	Net current period other comprehensive income				)						)
				(8,085			16,826			(19			8,722
	Balance at December 31, 2013		$	(10,971	)	$	(18,672	)	$	115		$	(29,528	)
	Other comprehensive income before				)			)						)
	reclassifications			(31,943			(24,186			—			(56,129
	Amounts reclassified from AOCI			—			1,709			3			1,712
	Net current period other comprehensive income				)			)						)
				(31,943			(22,477			3			(54,417
	Balance at December 31, 2014		$	(42,914	)	$	(41,149	)	$	118		$	(83,945	)
	Amounts reclassified out of AOCI for the three years ended December 31, 2014, 2013 and 2012, is displayed below:
	Amounts Reclassified from AOCI (a)
	(In thousands)											Affected Line Item in
												Consolidated
			2014			2013			2012			Statements of Income
	Amortization of defined pension items:
	Prior service cost		$	(20	)	$	(19	)	$	(18	)
	Actuarial loss			(2,727	)		(5,410	)		(3,632	)
	Transition obligation			–			(2	)		(18	)
			$	(2,747	)		(5,431	)		(3,668	)	Total before tax (b)
				1,038			2,022			1,381		Tax  benefit
			$	(1,709	)	$	(3,409	)	$	(2,287	)	Net of tax
	Gains and losses on cash flow hedges:
	Interest rate contracts		$	(20	)	$	(37	)	$	(27	)	Interest, net
	Foreign exchange contracts			10			10			—		Cost of sales
				(10	)		(27	)		(27	)	Total before tax
				7			14			8		Tax  benefit
			$	(3	)	$	(13	)	$	(19	)	Net of tax
	Total reclassifications for the period		$	(1,712	)	$	(3,422	)	$	(2,306	)	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 13 for details regarding net periodic benefit costs for the Company’s U.S. and U.K. defined benefit plans).

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions	20. Acquisitions
	2014 Acquisition Agreement
	On July 15, 2014, the Company announced that it reached an agreement with Procter & Gamble do Brasil S.A. to acquire (through the Company’s Brazilian subsidiary) a sulfonation production facility in Bahia, Brazil, subject to customary closing conditions. The facility is located in northeastern Brazil and has 30,000 metric tons of surfactants capacity. The acquisition will become a part of the Company’s Surfactants segment. This is synergistic with the Company’s existing Vespasiano, Brazil, plant, and provides an opportunity to serve growing northeastern Brazil. The transaction is projected to close in the first or second quarter of 2015.
	2013 Acquisition
	On June 1, 2013, the Company acquired the North American polyester resins business of Bayer MaterialScience LLC (BMS). Prior to the acquisition, BMS was a North American producer of powder polyester resins for metal coating applications and liquid polyester resins for coatings, adhesives, sealants and elastomers (CASE) applications. The purchase included a 21,000-ton production facility in Columbus, Georgia, and a modern research and development laboratory for customer technical support and new product development. Infrastructure is in place to allow for future expansion. The acquisition has diversified the Company’s polyol product offering and is expected to accelerate the Company’s growth in CASE and PUSH (polyurethane systems house) applications. As of the acquisition date, the new business and acquired net assets became a part of the North American operations reporting unit included in the Company’s Polymers reportable segment.
	The total acquisition purchase price was $68,212,000 cash, of which $61,067,000 was paid at closing and $7,145,000, primarily for inventory, was paid over a three-month period (June 2013 through August 2013) pursuant to a transition services agreement with BMS. The acquisition was originally funded through the Company’s committed revolving credit agreement. Subsequent to closing on the acquisition, the Company completed a $100,000,000 private placement loan, which was used in part to finance the acquisition (see Note 6 for additional information regarding the private placement loan).
	In addition to the purchase price paid, the Company incurred $270,000 of acquisition-related expenses related to legal, consulting, valuation and accounting services. These costs were included in administrative expenses in the Company’s consolidated statement of income for the year ended December 31, 2013.
	The acquisition was accounted for as a business combination and, accordingly, the assets acquired and liabilities assumed as part of the acquisition were measured and recorded at their estimated fair values. The following table summarizes the assets acquired and liabilities assumed:
	(Dollars in thousands)	June 1, 2013
	Assets:
	Inventory	$	9,002
	Property, plant and equipment		37,000
	Identifiable intangible assets		17,800
	Goodwill		4,642
	Total assets acquired	$	68,444
	Liabilities:
	Accrued expenses		232
	Net assets acquired	$	68,212
	The acquired goodwill, which was assigned entirely to the Company’s North American operations reporting unit included in the Company’s Polymers reportable segment, is deductible for tax purposes. The goodwill reflects the potential marketing, manufacturing and raw material sourcing synergies of the new business with the Company’s existing polymer business. Identifiable intangible assets included a technology and manufacturing know-how license agreement ($7,900,000), a trademark/trade name ($3,800,000) and customer relationships ($6,100,000). The amortization periods for these intangibles at the time of acquisition were 8, 11 and 12 years, respectively. The purchase price allocation is final, and no purchase price allocation adjustments were made to the amounts originally recorded at the acquisition date.
	The following is pro forma financial information prepared under the assumption that the acquisition of the BMS North American polyester resins business occurred on January 1, 2012:
	Pro Forma Financial Information
	Unaudited
		Year Ended
		December 31
	(In thousands, except per share amounts)	2013		2012
	Net Sales	$	1,907,607	$	1,866,209
	Net Income Attributable to Stepan Company	$	73,609	$	80,353
	Net Income Per Common Share Attributable to Stepan Company:
	Basic	$	3.25	$	3.75
	Diluted	$	3.21	$	3.54
	The supplemental pro forma information is presented for illustrative purposes only and may not be indicative of the consolidated results that would have actually been achieved by the Company. Furthermore, future results may vary significantly from the results reflected in the pro forma information. The pro forma results include adjustments primarily related to amortization of acquired intangible assets, depreciation of the fair value adjustment of acquisition-date plant assets, interest on borrowings and tax expense. In addition, nonrecurring adjustments to pro forma net income include $270,000 of acquisition-related expenses and $558,000 of expense related to the fair value adjustment of the acquisition date inventory; such expenses were excluded from 2013 pro forma net income and included in pro forma net income for the year ended December 31, 2012.

Business_Restructuring_and_Ass

Business Restructuring and Asset Impairments	12 Months Ended
	Dec. 31, 2014
Restructuring And Related Activities [Abstract]
Business Restructuring and Asset Impairments	21.   Business Restructuring and Asset Impairments
	2014 Restructuring
	In the fourth quarter of 2014, a restructuring plan was approved that affects certain Company functions, principally the R&D function and to a lesser extent product safety and compliance and plant site accounting functions (primarily affecting the Surfactants segment). The objective of the plan is to better align staffing resources with the needs of the Company’s diversification and growth initiatives. In implementing the plan, management offered a voluntary retirement incentive to employees of the affected functions. By December 31, 2014, 13 employees accepted the voluntary termination incentive. As a result, the Company recognized a $1,722,000 charge against income for the three and twelve months ended December 31, 2014. The incentive pay is expected to be disbursed in the first quarter of 2015. Although the Company may realize some short-term cost savings from the action, the restructuring is not considered a cost savings initiative but rather an opportunity to create some staffing availability to reposition roles to meet changing business needs. Other costs for the restructuring are not expected to be material.
	2014 Asset Impairments
	In the fourth quarter of 2014, the Company wrote off the net book values of three assets, resulting in a charge against income of $2,287,000 for the three and twelve months ended December 31, 2014. All three assets were part of the Company’s Surfactants segment, although the write-off charges were excluded from Surfactants segment results. At the Company’s Singapore location (Asia Surfactants operations), $1,316,000 of engineering costs for an asset expansion project were reversed out of the Company’s construction-in-process account and into expense because management determined that, given the current business environment, the magnitude of the project could no longer be economically justified. At the Company’s Millsdale, Illinois, plant (North American Surfactants operations), a reactor used to manufacture certain surfactant products was no longer required and was retired and removed from service. The book value of the asset was $714,000.  The remaining $257,000 of impairment charges related to an administrative building at the Company’s United Kingdom site (European Surfactants operations) that was vacated and essentially abandoned in place in the fourth quarter of 2014.
	2013 Restructuring
	In the fourth quarter of 2013, the Company recorded a $1,040,000 restructuring charge for estimated severance expense related to an approved plan to reduce future costs and increase operating efficiencies by consolidating a portion of its North American Surfactants manufacturing operations (part of the Surfactants reportable segment). In the third quarter of 2014, the Company shut down certain production areas at its Canadian manufacturing site. Production in those areas was moved to other U.S. plants. This consolidation resulted in the elimination of 16 North American positions. Most of the remaining severance payments are expected to be made in the first quarter of 2015. Other restructuring costs for this plan were not material. Following is a reconciliation of the beginning and ending balances of the restructuring liability:
	(In thousands)	Severance
		Expense
	Restructuring liability at December 31, 2013	$	1,040
	Amounts paid		(420	)
	Foreign currency translation		(57	)
	Restructuring liability at December 31, 2014	$	563
	In connection with the planned business restructuring, the Company reduced the useful lives of the manufacturing assets in the affected areas of the Canadian plant. The change in useful lives resulted in accelerated depreciation expenses of $296,000 in 2013 and $1,825,000 in 2014. The depreciation expense was included in the cost of sales line of the consolidated statement of income.

Insurance_Recovery

Insurance Recovery	12 Months Ended
	Dec. 31, 2014
Extraordinary And Unusual Items [Abstract]
Insurance Recovery	22.   Insurance Recovery
	The Company received insurance recoveries of $3,730,000 and $1,188,000 in 2013 and 2012, respectively, for business interruption losses resulting from a May 2011 fire that damaged polyol manufacturing equipment at the Company’s plant site in Wesseling, Germany. The insurance recoveries were recorded as reductions of cost of sales in the consolidated statements of income for the years ended December 31, 2013 and 2012, respectively.

Purchase_of_the_Remaining_Inte

Purchase of the Remaining Interest in Stepan Philippines, Inc	12 Months Ended
	Dec. 31, 2014
Equity Method Investments And Joint Ventures [Abstract]
Purchase of the Remaining Interest in Stepan Philippines, Inc	23.   Purchase of the Remaining Interest in Stepan Philippines, Inc
	On March 22, 2012, the Company purchased the remaining interest in Stepan Philippines, Inc. (SPI), increasing the Company’s ownership share from 88.8 percent to 100 percent.   To acquire the remaining interest in SPI, the Company paid $2,000,000 of cash to the holder of the noncontrolling interest. As a result of this transaction, the Company’s equity (additional paid-in capital) increased by $551,000. In addition, $197,000 of cumulative translation adjustments (gains) that previously had been allocated to the noncontrolling interest was reclassified to the Company’s AOCI.

Statement_of_Cash_Flows_Noncas

Statement of Cash Flows - Noncash Investing and Financing Activities	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Statement of Cash Flows - Noncash Investing and Financing Activities	24. Statement of Cash Flows – Noncash Investing and Financing Activities
	Noncash financing activities for the years ended December 31, 2014, 2013 and 2012, included the receipt of shares of the Company’s common stock tendered in lieu of cash by employees exercising stock options. The tendered shares, which were owned by employees for more than six months, had values of $92,000 in 2013 (1,562 shares) and $8,400,000 in 2012 (176,114 shares) and were recorded as treasury stock. There were no tendered shares in lieu of cash for exercising stock options in 2014.  Noncash financing activities for the years ended December 31, 2013 and 2012 also included the issuance of 48,973 shares and 84,568 shares, respectively, of Company common stock (values of $2,999,000 and $3,659,000, respectively) related to the Company’s performance stock award plan. There was no issuance of shares in 2014 related to the Company’s performance stock award plan. Noncash investing activities included unpaid liabilities (accounts payable) incurred for fixed asset acquisitions of approximately $17,797,000 in 2014, $11,772,000 in 2013 and $10,467,000 in 2012.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	25. Subsequent Events
	In January 2015, the Company sold its specialty polyurethane systems product lines (kits) to J6 Polymers, LLC (J6). Kit products were part of the Company’s Polymers segment and accounted for approximately $2,800,000 of the Company’s 2014 net sales. The sale to J6 was for cash and included inventory as well as customer and supplier lists, formulations, manufacturing procedures and all other intellectual property associated with the manufacturing and selling of kits.  Prior to the sale, kits were produced by the Company and by third-party toll manufacturers on the Company’s behalf.  The products manufactured by the Company will continued to be produced for J6 during a transition period. As a result of the kits sales transaction, the Company expects to report a pretax gain of $2,500,000 to $3,000,000 in the first quarter of 2015.

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data	Selected Quarterly Financial Data
	(In thousands, except per share data)
	Unaudited
		2014
	Quarter	First			Second			Third			Fourth			Year
	Net Sales	$	477,442		$	504,111		$	491,429		$	454,231		$	1,927,213
	Gross Profit		63,024			71,589			65,099			49,851			249,563
	Operating Income		22,523			36,914			22,253			9,004			90,694
	Interest, net		(2,957	)		(3,021	)		(2,846	)		(2,617	)		(11,441	)
	Income Before Income Taxes		18,089			33,206			18,228			6,012			75,535
	Net Income		13,008			24,368			13,480			6,225			57,081
	Net Income Attributable to Stepan Company		13,018			24,353			13,491			6,239			57,101
	Per Diluted Share		0.57			1.06			0.59			0.27			2.49
		2013
	Quarter	First			Second			Third			Fourth			Year
	Net Sales	$	456,546		$	474,445		$	475,466		$	474,329		$	1,880,786
	Gross Profit		72,700			73,707			74,341			60,937			281,685
	Operating Income		28,294			35,869			31,085			13,905			109,153
	Interest, net		(2,179	)		(2,329	)		(2,987	)		(2,863	)		(10,358	)
	Income Before Income Taxes		25,273			32,200			27,847			10,310			95,630
	Net Income		18,997			22,654			20,149			10,537			72,337
	Net Income Attributable to Stepan Company		19,034			22,742			20,402			10,650			72,828
	Per Diluted Share		0.83			0.99			0.89			0.46			3.18

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations
	Stepan Company (the Company) operations consist predominantly of the production and sale of specialty and intermediate chemicals, which are sold to other manufacturers for use in a variety of end products. Principal markets for all products are manufacturers of cleaning and washing compounds (including detergents, shampoos, fabric softeners, toothpastes and household cleaners), paints, cosmetics, food, beverages, nutritional supplements, agricultural products, plastics, furniture, automotive equipment, insulation and refrigeration.
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires Company management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and all wholly and majority-owned subsidiaries in which the Company exercises controlling influence. The equity method is used to account for investments in which the Company exercises significant but noncontrolling influence. Intercompany balances and transactions are eliminated in consolidation.
	The Company is a partner in two joint ventures: Nanjing Stepan Jinling Chemical Limited Liability Company (Stepan China) in Nanjing, China, and TIORCO, LLC in Denver, Colorado. The Company has an 80 percent ownership interest in the Stepan China joint venture and exercises controlling influence. Therefore, Stepan China’s accounts are included in the Company’s consolidated financial statements. The joint venture partner’s interest in Stepan China’s net income is reported in the net income attributable to noncontrolling interests line of the consolidated statements of income. The joint venture partner’s interest in the net assets of Stepan China is reported in the noncontrolling interests line (a component of equity separate from Company equity) of the consolidated balance sheets.
	TIORCO, LLC is equally owned and controlled by the Company and Nalco Company (a subsidiary of Ecolab Inc.). The Company’s investment in TIORCO, LLC is accounted for using the equity method and is included in the other non-current assets line on the consolidated balance sheets. The Company’s share of TIORCO, LLC’s net earnings is included in the loss from equity in joint ventures line of the consolidated statements of income.
Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company considers all highly liquid investments with purchased maturities of three months or less to be cash equivalents.
	At December 31, 2014, the Company’s cash and cash equivalents totaled $85.2 million.  Cash in U.S. demand deposit accounts totaled $8.4 million and cash of the Company’s non-U.S. subsidiaries held outside the U.S. totaled $76.8 million as of December 31, 2014.
Receivables and Credit Risk	Receivables and Credit Risk
	Receivables are stated net of allowances for doubtful accounts and other allowances and primarily include trade receivables from customers, as well as nontrade receivables from suppliers, governmental tax agencies and others.
	The Company is exposed to credit risk on accounts receivable balances. This risk is mitigated by the Company’s large, diverse customer base, which is dispersed over various geographic regions and industrial sectors. No single customer comprised more than 10 percent of the Company’s consolidated net sales in 2014, 2013 or 2012.
	The Company maintains allowances for potential credit losses. Specific customer allowances are recorded when a review of customer creditworthiness and current economic conditions indicate that collection is doubtful. In addition, the Company maintains a general allowance as a percentage of total trade receivables. The general allowance percentage is periodically reviewed and adjusted based on historical bad debt losses of the Company.
	The Company also maintains other customer allowances that occur in the normal course of business. Such allowances are based on historical averages and trade receivable levels.
	The following is an analysis of the allowance for doubtful accounts and other accounts receivable allowances for the years ended December 31, 2014, 2013 and 2012:
	(In thousands)	2014			2013			2012
	Balance at January 1	$	5,945		$	5,533		$	5,214
	Provision charged to income		4,625			719			314
	Accounts written off, net of recoveries		(559	)		(307	)		5
	Balance at December 31	$	10,011		$	5,945		$	5,533
	The 2014 provision charged to income included a $2,388,000 bad debt allowance for a major Polymer customer that filed for protection under Chapter 11 of the U.S. Bankruptcy Code in September 2014. Also included in the 2014 provision charged to income were additional allowances for certain high risk accounts and for general reserves.
Inventories	Inventories
	Inventories are valued at cost, which is not in excess of market value, and include material, labor and plant overhead costs. The last-in, first-out (LIFO) method is used to determine the cost of the Company’s U.S. inventories. The first-in, first-out (FIFO) method is used for all other inventories. Inventories priced at LIFO as of December 31, 2014 and 2013, accounted for 67 and 64 percent of total inventories, respectively.
Property, Plant and Equipment	Property, Plant and Equipment
	Depreciation of property, plant and equipment is provided on a straight-line basis over the estimated useful lives of the assets. Lives used for calculating depreciation are generally 30 years for buildings and 15 years for building improvements. For assets classified as machinery and equipment, lives generally used for calculating depreciation expense range from 10 to 15 years for manufacturing equipment, five to 10 years for furniture and fixtures, three to five years for vehicles and three to 10 years for computer equipment and software. Manufacturing of chemicals is capital intensive with a large majority of the assets included in machinery and equipment representing manufacturing equipment. Major renewals and betterments are capitalized in the property accounts, while maintenance and repairs ($55,923,000, $48,683,000, and $45,072,000 in 2014, 2013 and 2012, respectively), which do not renew or extend the life of the respective assets, are charged to operations as incurred. Land is not depreciated. The cost of property retired or sold and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in income.
	Included in the computer equipment and software component of machinery and equipment are costs related to the acquisition and development of internal-use software. Capitalized costs for internal-use software include external direct costs of materials and services consumed in obtaining and developing the software. For development projects where major internal resources are committed, payroll and payroll-related costs incurred during the application development phase of the project are also capitalized. The capitalized costs are amortized over the useful lives of the software, which are generally three to 10 years. Costs incurred in the preliminary project phase are expensed.
	Interest charges on borrowings applicable to major construction projects are capitalized.
	Property, plant and equipment assets are tested for impairment when events indicate that impairment may have occurred.
Fair Value Measurements	Fair Value Measurements
	GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Furthermore, GAAP establishes a framework, in the form of a three-level hierarchy, for measuring fair value that prioritizes the inputs to valuation techniques used to measure fair value. The following describes the hierarchy levels:
	Level 1 - quoted prices in active markets for identical assets and liabilities.
	Level 2 - inputs other than quoted prices included within Level 1 that are directly or indirectly observable for the asset or liability, such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data.
	Level 3 - unobservable inputs which reflect the entity’s own assumptions about the assumptions market participants use in pricing the assets and liabilities.
	The Company applies the fair value measurement provisions of GAAP to any of its financial assets and liabilities that are carried at fair value on the consolidated balance sheets (see Note 2), its outstanding debt for disclosure purposes (also Note 6) and its pension plan assets (see Note 13).
	The Company also applies the fair value measurement requirements to nonrecurring fair value measurements of nonfinancial assets and liabilities recorded in conjunction with business combinations and as part of impairment reviews for goodwill and other long-lived assets.
Revenue Recognition	Revenue Recognition
	Revenue is recognized upon shipment of goods to customers, at which time title and risk of loss pass to the customer. For arrangements where the Company consigns product to a customer location, revenue is recognized when the customer uses the inventory. The Company records shipping and handling billed to a customer in a sales transaction as revenue. Costs incurred for shipping and handling are reported in cost of sales. Volume discounts due customers are estimated and recorded in the same period as the sales to which the discounts relate and reported as reductions of revenue in the consolidated statements of income.
Cost of Sales	Cost of Sales
	Cost of sales comprises raw material costs (including inbound freight expense to deliver the raw materials), manufacturing plant labor expenses and various manufacturing overhead expenses, such as utility, maintenance, operating supply, amortization and manufacturing asset depreciation expenses. Cost of sales also includes outbound shipping and handling expenses, inter-plant transfer costs and warehouse expenses.
Operating Expenses	Operating Expenses
	Selling expense comprises salary and the related fringe benefit expenses for marketing and sales personnel and operating costs, such as outside agent commissions, automobile rental and travel-related expenses, which support the sales and marketing functions. Bad debt charges and any depreciation expenses related to marketing assets (e.g., computers) are also classified as selling expense.
	Administrative expense comprises salary and the related fringe benefit expenses and operating costs for the Company’s various administrative functions, which include information services, finance, legal, and human resources. Compensation expense related to the Company’s deferred compensation plans and legal and environmental remediation expenses are also classified as administrative expense.
	The Company’s research and development costs are expensed as incurred. These expenses are aimed at discovery and commercialization of new knowledge with the intent that such effort will be useful in developing a new product or in bringing about a significant improvement to an existing product or process. Total research and development expenses were $27,236,000, $28,782,000 and $28,032,000 in 2014, 2013 and 2012, respectively. The remainder of research, development and technical service expenses reflected on the consolidated statements of income relates to technical services, which include routine product testing, quality control and sales support service.
Environmental Expenditures	Environmental Expenditures
	Environmental expenditures that relate to current operations are expensed in cost of sales. Expenditures that mitigate or prevent environmental contamination and that benefit future operations are capitalized as assets and depreciated on a straight-line basis over the estimated useful lives of the assets, which are typically 10 years.
	Estimated future expenditures that relate to an existing condition caused by past operations, and which do not contribute to current or future revenue generation, are recorded as liabilities, with the corresponding charge recorded in administrative expenses, when environmental assessments and/or remedial efforts are probable and the cost or range of possible costs can be reasonably estimated. When no amount within the range is a better estimate than any other amount, the minimum amount in the range is accrued. Some of the factors on which the Company bases its estimates include information provided by feasibility studies, potentially responsible party negotiations and the development of remedial action plans. Legal costs related to environmental matters are expensed as incurred (see Note 16 for environmental contingencies).
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets
	The Company’s intangible assets include patents, agreements not to compete, trademarks, customer lists, technological and manufacturing know-how and goodwill, all of which were acquired as part of business or product line acquisitions. Intangible assets other than goodwill are determined to have either finite or indefinite useful lives. The Company currently has no indefinite-life intangible assets. The values for intangible assets with finite lives are amortized over the useful lives of the assets. In addition, finite-life intangible assets are tested for impairment when events or changes in circumstances indicate that the carrying value of an intangible asset may not be recoverable. Goodwill is not amortized. Goodwill is tested for impairment at least annually or more frequently if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit to which goodwill relates below the reporting unit’s carrying value. For more details see Note 4.
Income Taxes	Income Taxes
	The provision for income taxes is determined using the asset and liability method, under which deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities. Deferred tax assets or liabilities are computed using the currently enacted tax rates that apply to taxable income in effect for the years in which those tax assets and liabilities are expected to be realized or settled. Deferred tax assets and liabilities are adjusted for changes in tax rates or laws, and the effects of the changes are recorded in income in the period of enactment. Valuation allowances are recorded to reduce deferred tax assets when the Company determines that it is more likely than not that a tax benefit will not be realized.
	The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained upon examination by tax authorities. If the tax position meets the more-likely-than-not threshold, the tax benefit recognized in the consolidated financial statements is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon effective settlement. Unrecognized tax benefits, which are differences between the tax position taken on a tax return and the amounts recognized in the financial statements, are recorded either as an increase to a tax liability or as a decrease to an income tax receivable. The Company includes estimated interest and penalty amounts related to the unrecognized tax benefits in the tax provision.
	See Note 9 for detailed information about income taxes.
Translation of Foreign Currencies	Translation of Foreign Currencies
	For the Company’s consolidated foreign subsidiaries whose functional currency is the local foreign currency, assets and liabilities are translated into U.S. dollars at exchange rates in effect at year end and revenues and expenses are translated at average exchange rates for the year. Any resulting translation adjustments are included in the consolidated balance sheets in the accumulated other comprehensive loss line of stockholders’ equity. Gains or losses on foreign currency transactions are reflected in the other, net caption of the consolidated statements of income. The Company has one foreign subsidiary whose functional currency is the U.S. dollar. For this subsidiary, nonmonetary assets and liabilities are translated at historical rates, monetary assets and liabilities are translated at exchange rates in effect at year end, revenues and expenses are translated at average exchange rates for the year and translation gains and losses are included in the other, net caption of the consolidated statements of income.
Stock-Based Compensation	Stock-Based Compensation
	The Company grants stock options, performance stock awards and stock appreciation rights (SARs) to certain employees under its incentive compensation plans. The Company calculates the fair values of stock options, performance stock awards and SARs on the date such instruments are granted. The fair values of the stock option and performance stock awards are then recognized as compensation expense over the vesting periods of the instruments. The Company’s SARs are cash-settled and accounted for as liabilities that must be re-measured at fair value at the end of each reporting period. Compensation expense for each reporting period is calculated as the period-to-period change (or portion of the change, depending on the proportion of the vesting period that has been completed at the reporting date) in the fair value of the SARs. See Note 11 for detailed information about the Company’s stock-based compensation.
Earnings Per Share	Earnings Per Share
	Basic earnings per share amounts are computed based on the weighted-average number of common shares outstanding. Net income used in computing basic earnings per share is net income attributable to the Company reduced by dividends paid to preferred stockholders. Diluted earnings per share amounts are based on the weighted-average number of common shares outstanding plus the increased number of common shares that would be outstanding assuming the exercise of certain outstanding stock options (under the treasury stock method), the conversion of the convertible preferred stock (when such conversion would have the effect of reducing earnings per share), and contingent stock awards that are part of the Company’s incentive stock-based compensation program (see Note 11). See Note 18 for detailed information about the Company’s earnings per share calculations.
Comprehensive Income and Accumulated Other Comprehensive Income	Comprehensive Income and Accumulated Other Comprehensive Income
	Comprehensive income includes net income and all other non-owner changes in equity that are not reported in net income. Comprehensive income is disclosed in the consolidated statements of comprehensive income. Accumulated other comprehensive income (AOCI) is reported as a component of stockholders’ equity in the Company’s consolidated balance sheets. See Note 19 for detailed information regarding changes in the Company’s AOCI and reclassifications out of AOCI to income.
Segment Reporting	Segment Reporting
	The Company reports financial and descriptive information about its reportable operating segments. Operating segments are components of the Company that have separate financial information that is regularly evaluated by the chief operating decision maker to assess segment performance and allocate resources. The Company discloses segment revenue, operating income, assets, capital expenditures and depreciation and amortization expenses. Enterprise-wide financial information about the geographic locations in which the Company earns revenues and holds assets is also disclosed (see Note 17).
Derivative Instruments	Derivative Instruments
	Derivative instruments are recognized in the consolidated balance sheets as either assets or liabilities measured at fair value. For derivative instruments that are not designated as hedging instruments, changes in the fair values of the derivative instruments are recognized currently in earnings. For derivative instruments designated as hedging instruments, depending on the nature of the hedge, changes in the fair values of the derivative instruments are either offset in earnings against changes in the fair values of the hedged items or recognized in AOCI until the hedged transaction is recognized in earnings. At the time a hedging relationship is designated, the Company establishes the method it will use for assessing the effectiveness of the hedge and the measurement approach for determining the ineffective aspect of the hedge.   Company policy prohibits the use of derivative instruments for trading or speculative purposes. See Note 3 for further information regarding the Company’s use of derivatives.
	At December 31, 2014, the Company held open forward contracts for the purchase of 1.6 million dekatherms of natural gas in 2015 and 2016 at a cost of $6,558,000. The Company uses forward contracts to minimize its exposure to volatile natural gas prices. Because the Company anticipates taking delivery of the natural gas for use in its operations, the forward contracts qualify for the normal purchase exception election provided under U.S. GAAP for derivative instruments. The Company has elected the exceptions for such contracts. As a result, the forward contracts are not accounted for as derivative instruments. The cost of natural gas is charged to expense at the time the natural gas is delivered and used.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In February 2013, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2013-04, Liabilities (Topic 405), Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation is Fixed at the Reporting Date. This update requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation is fixed at the reporting date, as the sum of a) the amount the reporting entity agreed to pay on the basis of its arrangement among its co-obligors and b) any additional amount the reporting entity expects to pay on behalf of its co-obligors. The update also requires an entity to disclose the nature and amount of the obligation as well as other information about those obligations. The requirements of ASU No. 2013-04 were effective on a retrospective basis for interim and annual periods beginning after December 15, 2013. Because the Company had no applicable obligations resulting from joint and several liability arrangements, adoption of ASU No. 2013-04 did not impact on the Company’s financial position, results of operations or cash flows.
	In July 2013, the FASB issued ASU No. 2013-11, Income Taxes (Topic 740), Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The update clarifies that unrecognized tax benefits related to a net operating loss carryforward, or similar tax loss, or tax credit carryforward, should generally be presented in the financial statements as a reduction to a deferred tax asset. The requirements of ASU No. 2013-11 were effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. Because the Company had no unrecognized tax benefits in jurisdictions where a net operating loss carryforward, or similar tax loss, or tax credit carryforward existed, adoption of the new guidance had no impact on the Company’s financial position, results of operations or cash flows.
	In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The update amends the definition of a discontinued operation, changes the criteria for reporting discontinued operations and requires expanded disclosures for discontinued operations and new disclosures about disposal transactions that do not meet the discontinued operations criteria. Under the new guidance, a discontinued operation is defined as a disposal of a component or group of components that is disposed of or is classified as held for sale and represents a strategic shift that has or will have a major effect on an entity's operations and financial results. The requirements of ASU No. 2014-08 are effective for fiscal years, and interim periods within those years, beginning after December 15, 2014, with early adoption permitted. Upon adoption of the ASU, the Company will assess discontinued operations using the new criteria and will provide the necessary disclosures for discontinued operations and other disposal activities. This ASU is not expected to have an effect on the Company’s financial position, results of operations or cash flows.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The standard, which is the result of a joint project by the FASB and the International Accounting Standards Board, outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. In addition, the ASU requires expanded disclosures about revenue recognition that enable the users of the financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. ASU No. 2014-09 supersedes most of the previous revenue recognition guidance. For public entities, the new guidance is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. An entity may use either a full retrospective or a modified retrospective approach to adopt the requirements of the new standard. The Company is in the process of determining the effects, if any, that adoption of ASU No. 2014-09 will have on Company financial position, results of operations and cash flows.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Allowance for Doubtful Accounts and Other Accounts Receivable Allowance	The following is an analysis of the allowance for doubtful accounts and other accounts receivable allowances for the years ended December 31, 2014, 2013 and 2012:
	(In thousands)	2014			2013			2012
	Balance at January 1	$	5,945		$	5,533		$	5,214
	Provision charged to income		4,625			719			314
	Accounts written off, net of recoveries		(559	)		(307	)		5
	Balance at December 31	$	10,011		$	5,945		$	5,533

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Values and Related Carrying Values of Debt	At December 31, 2014 and 2013, the fair values and related carrying values of debt, including current maturities, were as follows:
	(In thousands)	31-Dec
		2014		2013
	Fair value	$	285,441	$	276,069
	Carrying value		273,931		270,623
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 December 31, 2014 and 2013, and the level within the fair value hierarchy in which the fair value measurement falls:
	(In thousands)	December		Level 1		Level 2		Level 3
		2014
	Mutual fund assets	$	20,217	$	20,217	$	─	$	─
	Derivative assets:
	Foreign currency contracts		73		─		73		─
	Total assets at fair value	$	20,290	$	20,217	$	73	$	─
	Derivative liabilities:
	Foreign currency contracts	$	628	$	─	$	628	$	─
	(In thousands)	December		Level 1		Level 2		Level 3
		2013
	Mutual fund assets	$	18,305	$	18,305	$	—	$	—
	Derivative assets:
	Foreign currency contracts		74		—		74		—
	Total assets at fair value	$	18,379	$	18,305	$	74	$	—
	Derivative liabilities:
	Foreign currency contracts	$	165	$	—	$	165	$	—
	Interest rate contracts		20		—		20		—
	Total liabilities at fair value	$	185	$	—	$	185	$	—

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Value of Goodwill and Other Intangible Assets	The changes in the carrying value of goodwill for the years ended December 31, 2014 and 2013, were as follows:
	(In thousands)		Surfactants						Polymer					Specialty Products				Total
			Segment						Segment					Segment
			2014			2013			2014			2013		2014		2013		2014			2013
	Balance as of January 1
	Goodwill		$	9,107		$	9,246		$	5,603		$	937	$	483	$	483	$	15,193		$	10,666
	Accumulated impairment loss			(3,467	)		(3,467	)		—			—		—		—		(3,467	)		(3,467	)
	Goodwill, net			5,640			5,779			5,603			937		483		483		11,726			7,199
	Goodwill acquired (1)			—			—			—			4,642		—		—		—			4,642
	Foreign currency translation			(82	)		(139	)		(142	)		24		—		—		(224	)		(115	)
	Balance as of December 31
	Goodwill			9,025			9,107			5,461			5,603		483		483		14,969			15,193
	Accumulated impairment loss			(3,467	)		(3,467	)		—			—		—		—		(3,467	)		(3,467	)
	Goodwill, net		$	5,558		$	5,640		$	5,461		$	5,603	$	483	$	483	$	11,502		$	11,726
	-1	See Note 20 for information regarding the goodwill acquired in business combinations.
Components of Other Intangible Assets and Changes in Gross Carrying Values	The following table presents the components of other intangible assets, all of which have finite lives, as of December 31, 2014 and 2013. The year-over-year changes in gross carrying values resulted from the effects of foreign currency translation.
	(In thousands)		Gross Carrying Value						Accumulated Amortization
			31-Dec						31-Dec
			2014			2013			2014			2013
	Other Intangible Assets:
	Patents		$	6,947		$	6,947		$	2,096		$	1,498
	Trademarks			4,087			4,087			748			345
	Customer lists			8,082			8,094			1,871			1,098
	Know-how (a)			8,273			8,313			1,871			831
	Total		$	27,389		$	27,441		$	6,586		$	3,772
	(a)	Know-how includes intellectual property rights covering proprietary information, written formulae, trade secrets or secret processes, inventions and developmental products (whether patentable or not), discoveries, improvements, compositions, manufacturing processes, manuals, specifications and technical data.
Estimated Amortization Expense for Identifiable Intangibles Assets	Estimated amortization expense for identifiable intangibles assets for each of the five succeeding fiscal years is as follows:
	(In thousands)
	For year ended 12/31/15		$	2,825
	For year ended 12/31/16			2,681
	For year ended 12/31/17			2,565
	For year ended 12/31/18			2,565
	For year ended 12/31/19			2,565

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory Disclosure [Abstract]
Composition of Inventories	The composition of inventories was as follows:
		December 31
	(In thousands)	2014		2013
	Finished products	$	126,157	$	123,211
	Raw materials		57,076		49,156
	Total inventories	$	183,233	$	172,368

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt	Debt comprised the following at December 31, 2014 and 2013:
	(In thousands)	Maturity			December 31,			December 31,
		Dates			2014			2013
	Unsecured private placement notes
	3.86%		2019-2025		$	100,000		$	100,000
	4.86%		2017-2023			65,000			65,000
	5.88%		2016-2022			40,000			40,000
	5.69%		2015-2018			22,857			28,571
	6.86%		2015			4,284			8,570
	Unsecured U.S. bank debt		2019			20,000			─
	Debt of foreign subsidiaries
	Unsecured bank debt, foreign currency		2015			12,043			19,488
	Unsecured bank term loan, foreign currency		2021			4,840			─
	Secured bank term loan, foreign currency		2015			2,723			5,843
	Secured bank debt, foreign currency		2015			1,638			2,153
	Unsecured bank debt, U.S. dollars		2015			546			998
	Total debt				$	273,931		$	270,623
	Less current maturities					27,034			35,377
	Long-term debt				$	246,897		$	235,246
Schedule of Net Interest Expense	Net interest expense for the years ended December 31, 2014, 2013 and 2012, comprised the following:
	(In thousands)	2014			2013			2012
	Interest expense	$	12,542		$	11,104		$	9,998
	Interest income		(262	)		(57	)		(112	)
			12,280			11,047			9,886
	Capitalized interest		(839	)		(689	)		(287	)
	Interest expense, net	$	11,441		$	10,358		$	9,599

Leased_Properties_Tables

Leased Properties (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Consolidated Company Minimum Future Rental Payments Under Operating Leases With Terms in Excess of One Year	Consolidated Company minimum future rental payments under operating leases with terms in excess of one year as of December 31, 2014, are:
	(In thousands)	Year		Amount
			2015	$	4,523
			2016		3,522
			2017		2,163
			2018		1,866
			2019		1,822
			Subsequent to 2019		16,651
			Total minimum future rental payments	$	30,547

Other_Net_Tables

Other, Net (Tables)	12 Months Ended
	Dec. 31, 2014
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)	2014			2013			2012
	Foreign exchange loss	$	(220	)	$	(1,495	)	$	(304	)
	Investment related income		1,269			1,055			173
	Realized and unrealized gain on investments		241			2,611			1,460
	Other, net	$	1,290		$	2,171		$	1,329

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Provision for Taxes on Income and Other Related Income Before Taxes	The provisions for taxes on income and the related income before taxes for the years ended December 31, 2014, 2013 and 2012, were as follows:
	(In thousands)	2014			2013			2012
	Taxes on Income
	Federal
	Current	$	3,362		$	9,744		$	23,744
	Deferred		4,338			(285	)		(525	)
	State
	Current		782			1,223			1,999
	Deferred		643			(680	)		(537	)
	Foreign
	Current		9,004			12,067			10,158
	Deferred		325			1,224			1,196
	Total	$	18,454		$	23,293		$	36,035
	Income before Taxes
	Domestic	$	34,091		$	50,626		$	80,371
	Foreign		41,444			45,004			35,351
	Total	$	75,535		$	95,630		$	115,722
Summary of Variations Between the Effective and Statutory U.S. Federal Income Tax Rates	The variations between the effective and statutory U.S. federal income tax rates are summarized as follows:
	(In thousands)	2014			%			2013			%			2012			%
		Amount						Amount						Amount
	Federal income tax provision at statutory tax rate	$	26,437			35		$	33,471			35		$	40,503			35
	State tax provision on income less applicable federal tax benefit		926			1.2			353			0.4			1,470			1.3
	Foreign income taxed at different rates		(5,175	)		(6.9	)		(2,509	)		(2.6	)		(1,172	)		(1.0	)
	Repatriation of foreign earnings		83			0.1			146			0.2			24			—
	Domestic production activities deduction		(312	)		(0.4	)		(991	)		(1.0	)		(1,446	)		(1.2	)
	Nontaxable foreign interest income		(2,435	)		(3.2	)		(2,614	)		(2.7	)		(2,690	)		(2.3	)
	Nontaxable biodiesel excise credit income		(130	)		(0.2	)		(2,347	)		(2.5	)		—			—
	U.S. tax credits		(1,086	)		(1.4	)		(2,209	)		(2.3	)		—			—
	Non-deductible expenses and other items, net		146			0.2			(7	)		(0.1	)		(654	)		(0.7	)
	Total income tax provision	$	18,454			24.4		$	23,293			24.4		$	36,035			31.1
Schedule Showing Tax Effects of Significant Temporary Differences Representing Deferred Tax Assets and Liabilities	At December 31, 2014 and 2013, the tax effects of significant temporary differences representing deferred tax assets and liabilities were as follows:
	(In thousands)	2014			2013
	Deferred Tax Liabilities:
	Depreciation	$	(63,104	)	$	(57,113	)
	Amortization of intangibles		—			(49	)
	Unrealized foreign exchange loss		(838	)		(910	)
	Other		(1,159	)		(823	)
		$	(65,101	)	$	(58,895	)
	Deferred Tax Assets:
	Pensions	$	18,775		$	5,640
	Deferred revenue		1,650			3,058
	Other accruals and reserves		13,230			12,061
	Inventories		1,957			1,158
	Legal and environmental accruals		9,505			6,594
	Deferred compensation		15,636			20,510
	Bad debt and rebate reserves		4,618			3,018
	Subsidiaries net operating loss carryforwards		727			899
	Tax credit carryforwards		2,064			915
		$	68,162		$	53,853
	Valuation Allowance	$	(1,506	)	$	(1,302	)
	Net Deferred Tax (Liabilities) Assets	$	1,555		$	(6,344	)
	Reconciliation to Consolidated Balance Sheet:
	Current deferred tax assets	$	15,364		$	12,637
	Non-current deferred tax assets (in other non-current assets)		2,044			1,658
	Current deferred tax liabilities (in accrued liabilities)		(49	)		(23	)
	Non-current deferred tax liabilities		(15,804	)		(20,616	)
	Net Deferred Tax (Liabilities) Assets	$	1,555		$	(6,344	)
Schedule of Reconciliations of Unrecognized Tax Benefits	Below are reconciliations of the January 1 and December 31 balances of unrecognized tax benefits for 2014, 2013 and 2012:
	(In thousands)	2014			2013			2012
	Unrecognized tax benefits, opening balance	$	240		$	289		$	1,232
	Gross increases – tax positions in prior period		—			27			—
	Gross decreases – tax positions in prior period		—			(41	)		(569	)
	Gross increases – current period tax positions		261			17			44
	Settlements		—			—			—
	Foreign currency translation		(13	)		5			23
	Lapse of statute of limitations		(24	)		(57	)		(441	)
	Unrecognized tax benefits, ending balance	$	464		$	240		$	289

Stockbased_Compensation_Tables

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Fair Value Assumptions for Stock Options	The risk-free rate is the U.S. Treasury note rate that corresponds to the expected option term at the date of grant.
		For the Years Ended December 31
		2014		2013	2012
	Expected dividend yield	1.77%		2.01%	2.10%
	Expected volatility	42.04%		42.48%	43.19%
	Expected term	7.3 years		7.4 years	7.4 years
	Risk-free interest rate	2.18%		1.53%	1.41%
Summary of Stock Option Activity	A summary of stock option activity for the year ended December 31, 2014 is presented below:
		Shares			Weighted-		Weighted-		Aggregate
					Average		Average		Intrinsic Value
					Exercise Price		Remaining		$0
							Contractual
							Term
	Options
	Outstanding at January 1, 2014		505,112		$	30.8
	Granted		53,175			61.69
	Exercised		-67,029			26.17
	Forfeited		-10,522			54.41
	Outstanding at December 31, 2014		480,736			34.35		4.43	$	2,757
	Vested or expected to vest at December 31, 2014		480,736			34.35		4.43		2,757
	Exercisable at December 31, 2014		384,457			27.37		3.37		4,885
Summary of Stock Award Activity	A summary of stock award activity for the year ended December 31, 2014, is presented below:
		Shares			Weighted-Average Grant
					Date
					Fair Value
	Unvested Stock Awards
	Unvested at January 1, 2014		221,090		$	48.75
	Granted		89,234			59.52
	Vested		—			—
	Forfeited		127,314			43.12
	Unvested at December 31, 2014		183,010			57.92
Summary of SARs Activity	A summary of SARs activity for the year ended December 31, 2014 is presented below:
		Shares			Weighted-		Weighted-		Aggregate
					Average		Average		Intrinsic Value
					Exercise Price		Remaining		$0
							Contractual
							Term
	SARs
	Outstanding at January 1, 2014		148,311		$	54.6
	Granted		116,843			61.62
	Forfeited		(33,972	)		55.99
	Outstanding at December 31, 2014		231,182			57.94		8.4	$	(4,130	)

Postretirement_Benefit_Plans_T

Postretirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Obligations and Funded Status
	Obligations and Funded Status at December 31
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Change in benefit obligation
	Benefit obligation at beginning of year	$	144,508		$	157,051		$	21,095		$	21,722
	Interest cost		6,936			6,424			964			899
	Actuarial (gain) loss		23,547			(14,142	)		3,176			(1,365	)
	Benefits paid		(5,584	)		(4,825	)		(822	)		(521	)
	Foreign exchange impact		—			—			(1,430	)		360
	Benefit obligation at end of year	$	169,407		$	144,508		$	22,983		$	21,095
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Change in plan assets
	Fair value of plan assets at beginning of year	$	133,264		$	124,682		$	22,204		$	18,390
	Actual return on plan assets		(2,929	)		13,225			1,902			2,840
	Employer contributions		1,618			182			1,004			949
	Benefits paid		(5,584	)		(4,825	)		(822	)		(521	)
	Foreign exchange impact		—			—			(1,430	)		546
	Fair value of plan assets at end of year	$	126,369		$	133,264		$	22,858		$	22,204
	Over (Under) funded status at end of year	$	(43,038	)	$	(11,244	)	$	(125	)	$	1,109
Schedule of Amounts Recognized in Balance Sheets	The amounts recognized in the consolidated balance sheets at December 31 consisted of
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Non-current asset	$	—		$	818		$	—		$	1,109
	Current liability		(185	)		(185	)		—			—
	Non-current liability		(42,853	)		(11,877	)		(125	)		—
	Net amount recognized	$	(43,038	)	$	(11,244	)	$	(125	)	$	1,109
Amounts Recognized in Accumulated Other Comprehensive Income
	The amounts recognized in accumulated other comprehensive income at December 31 consisted of
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Net actuarial loss	$	60,114		$	26,802		$	4,724		$	2,147
Information for Pension Plans with Projected Benefit Obligations in Excess of Plan Assets	Below is information for pension plans with projected benefit obligations in excess of plan assets at December 31:
	(In thousands)	United States						United Kingdom
		2014			2013			2014			2013
	Projected benefit obligation	$	169,407		$	113,865		$	22,983		$	—
	Accumulated benefit obligation		169,407			113,865			22,983			—
	Fair value of plan assets		126,369			101,803			22,858			—
Components of Net Periodic Benefit Cost	Net periodic benefit costs for the years ended December 31, 2014, 2013 and 2012, were as follows:
	(In thousands)	United States									United Kingdom
		2014			2013			2012			2014			2013			2012
	Interest cost	$	6,936		$	6,424		$	6,880		$	964		$	899		$	841
	Expected return on plan assets		(9,523	)		(8,828	)		(8,423	)		(1,303	)		(941	)		(888	)
	Amortization of net actuarial loss		2,687			5,109			3,573			—			288			49
	Net periodic benefit cost	$	100		$	2,705		$	2,030		$	(339	)	$	246		$	2
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income	Other changes in plan assets and benefit obligations recognized in other comprehensive income for the years ended December 31, 2014, 2013 and 2012, were as follows:
	(In thousands)	United States									United Kingdom
		2014			2013			2012			2014			2013			2012
	Net actuarial (gain) loss	$	35,999		$	(18,539	)	$	4,622		$	2,577		$	(3,264	)	$	3,111
	Amortization of net actuarial loss		(2,687	)		(5,109	)		(3,573	)		—			(288	)		(49	)
	Total recognized in other comprehensive income	$	33,312		$	(23,648	)	$	1,049		$	2,577		$	(3,552	)	$	3,062
	Total recognized in net periodic benefit cost and other comprehensive income	$	33,412		$	(20,943	)	$	3,079		$	2,238		$	(3,306	)	$	3,064
Estimated Amounts Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost	The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2015 are as follows:
	(In thousands)	United States			United Kingdom
	Net actuarial loss	$	4,597		$	184
Estimated Future Benefit Payments	Estimated Future Benefit Payments
	(In thousands)	United States			United Kingdom
	2015	$	6,153		$	558
	2016		6,714			584
	2017		7,322			620
	2018		7,821			631
	2019		8,283			639
	2020-2024		48,207			3,721
Defined Contribution Plan Expenses for Company's Retirement Savings Plans and Profit Sharing Plan	Defined contribution plan expenses for the Company’s retirement savings plans and profit sharing plan were as follows:
	(In thousands)	2014			2013			2012
	Retirement savings plans	$	4,565		$	4,500		$	4,284
	Profit sharing plan		3,619			4,804			5,762
	Total	$	8,184		$	9,304		$	10,046
United States [Member]
Company's Asset Allocations for its U.S. and U.K Pension Plans	The Company’s asset allocations for its U.S. pension plans at December 31, 2014 and 2013, by asset category, were as follows:
		December 31, 2014
	(In thousands)	Level 1			Level 2			Level 3			Total
	Cash and Cash Equivalents	$	—		$	1,963		$	—		$	1,963
	Equity Securities
	U.S. Equities		34,885			—			—			34,885
	Non-U.S. Equities		12,478			—			—			12,478
	Employer Securities		21,575			—			—			21,575
	Total Equities		68,938			—			—			68,938
	Fixed Income Securities
	U.S. Corporate Bonds		—			27,676			—			27,676
	U.S. Government and Agency Bonds		350			10,327			—			10,677
	Municipal Bonds		—			3,352			—			3,352
	Other Bonds		—			6,155			—			6,155
	Total Fixed Income		350			47,510			—			47,860
	Real Estate		5,585			—			—			5,585
	Commodities		2,023			—			—			2,023
	Total	$	76,896		$	49,473		$	—		$	126,369
		December 31, 2013
	(In thousands)	Level 1			Level 2			Level 3			Total
	Cash and Cash Equivalents	$	—		$	2,471		$	—		$	2,471
	Equity Securities
	U.S. Equities		32,567			—			—			32,567
	Non-U.S. Equities		11,892			—			—			11,892
	Employer Securities		37,823			—			—			37,823
	Total Equities		82,282			—			—			82,282
	Fixed Income Securities
	U.S. Corporate Bonds		—			24,733			—			24,733
	U.S. Government and Agency Bonds		2,526			6,575			—			9,101
	Municipal Bonds		—			3,116			—			3,116
	Other Bonds		—			4,559			—			4,559
	Total Fixed Income		2,526			38,983			—			41,509
	Real Estate		6,090			—			—			6,090
	Commodities		912			—			—			912
	Total	$	91,810		$	41,454		$	—		$	133,264
United Kingdom [Member]
Company's Asset Allocations for its U.S. and U.K Pension Plans	The Company’s asset allocations for its U.K. pension plans at December 31, 2014 and 2013, by asset category, were as follows:
		December 31, 2014
	(In thousands)	Level 1			Level 2			Level 3			Total
	Cash	$	1,176		$	—		$	—		$	1,176
	Equity Securities
	Pooled Pension Funds		—			15,322			—			15,322
	Fixed Income
	Pooled Pension Funds		—			3,642			—			3,642
	Real Estate
	Pooled Pension Funds		—			477			—			477
	Insurance Contracts		—			—			2,241			2,241
	Total	$	1,176		$	19,441		$	2,241		$	22,858
		December 31, 2013
	(In thousands)	Level 1			Level 2			Level 3			Total
	Cash	$	412		$	—		$	—		$	412
	Equity Securities
	Pooled Pension Funds		—			15,397			—			15,397
	Fixed Income
	Pooled Pension Funds		—			3,550			—			3,550
	Real Estate
	Pooled Pension Funds		—			419			—			419
	Insurance Contracts		—			—			2,426			2,426
	Total	$	412		$	19,366		$	2,426		$	22,204
Fair Value Changes within Asset Categories for which Fair Value Measurements Use Significant Unobservable Inputs (Level 3) Defined Benefit United States Plans and United Kingdom Plans	Fair value changes within asset categories for which fair value measurements use significant unobservable inputs (Level 3) were as follows during 2013 and 2014:
	(In thousands)	Insurance Contracts
	Fair value, December 31, 2012	$	2,437
	Sale proceeds (benefit payments)		(175	)
	Change in unrealized gain		120
	Foreign exchange impact		44
	Fair value, December 31, 2013	$	2,426
	Sale proceeds (benefit payments)		(178	)
	Change in unrealized gain		135
	Foreign exchange impact		(142	)
	Fair value, December 31, 2014	$	2,241
Defined Benefit Plan Periodic Costs [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligations/Net Periodic Benefit Costs	The weighted-average assumptions used to determine net periodic benefit costs for years ended December 31 were as follows:
		United States									United Kingdom
		2014			2013			2012			2014			2013			2012
	Discount rate		4.87	%		4.17	%		5.06	%		4.6	%		4.3	%		4.9	%
	Expected long-term return on plan assets		7.75	%		7.75	%		7.75	%		5.84	%		5.25	%		5.46	%
Benefit Obligation [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligations/Net Periodic Benefit Costs	The weighted-average assumptions used to determine benefit obligations at December 31 were as follows:
		United States						United Kingdom
		2014			2013			2014			2013
	Discount rate		4.09	%		4.87	%		3.5	%		4.6	%

Accrued_Liabilities_Tables

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Payables And Accruals [Abstract]
Composition of Accrued Liabilities	The composition of accrued liabilities was as follows:
		December 31
	(In thousands)	2014		2013
	Accrued payroll and benefits	$	28,060	$	39,722
	Accrued customer rebates		17,395		15,514
	Other accrued liabilities		20,041		21,103
	Total accrued liabilities	$	65,496	$	76,339

Other_NonCurrent_Liabilities_T

Other Non-Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Composition of other non-current liabilities	The composition of other non-current liabilities was as follows:
		31-Dec
	(In thousands)	2014		2013
	Deferred revenue	$	3,318	$	4,045
	Environmental and legal matters		20,583		13,133
	Deferred compensation liability		37,790		50,728
	Pension liability		45,738		14,923
	Other non-current liabilities		5,427		5,777
	Total other non-current liabilities	$	112,856	$	88,606

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Operating Segment	Segment data for the three years ended December 31, 2014, 2013 and 2012, are as follows:
	(In thousands)		Surfactants			Polymers			Specialty			Segment
									Products			Totals
	2014
	Net sales		$	1,296,638		$	550,966		$	79,609		$	1,927,213
	Operating income			60,778			60,690			10,487			131,955
	Assets			741,677			320,640			67,588			1,129,905
	Capital expenditures			70,796			22,409			5,618			98,823
	Depreciation and			41,483			18,433			2,792			62,708
	amortization expenses
	2013
	Net sales		$	1,317,164		$	483,361		$	80,261		$	1,880,786
	Operating income			100,201			54,536			10,902			165,639
	Assets			710,521			292,015			68,413			1,070,949
	Capital expenditures			66,266			18,804			6,370			91,440
	Depreciation and			36,400			16,351			2,631			55,382
	amortization expenses
	2012
	Net sales		$	1,305,800		$	423,959		$	73,978		$	1,803,737
	Operating income			118,591			48,130			12,242			178,963
	Assets			692,891			199,013			58,810			950,714
	Capital expenditures			56,236			19,266			5,815			81,317
	Depreciation and			34,036			13,328			2,270			49,634
	amortization expenses
Reconciliation of Segment Information to Consolidated Financial Statements	Below are reconciliations of segment data to the consolidated financial statements:
	(In thousands)		2014			2013			2012
	Operating income - segment totals		$	131,955		$	165,639		$	178,963
	Business restructuring and asset impairments (a)			(4,009	)		(1,040	)		—
	Unallocated corporate expenses (b)			(37,252	)		(55,446	)		(50,247	)
	Total operating income			90,694			109,153			128,716
	Interest expense, net			(11,441	)		(10,358	)		(9,599	)
	Loss from equity in joint ventures			(5,008	)		(5,336	)		(4,724	)
	Other, net			1,290			2,171			1,329
	Consolidated income before income taxes		$	75,535		$	95,630		$	115,722
	Assets - segment totals		$	1,129,905		$	1,070,949		$	950,714
	Unallocated corporate assets (c)			32,109			96,253			34,764
	Consolidated assets		$	1,162,014		$	1,167,202		$	985,478
	Capital expenditures - segment totals		$	98,823		$	91,440		$	81,317
	Unallocated corporate expenditures			2,996			1,425			1,842
	Consolidated capital expenditures		$	101,819		$	92,865		$	83,159
	Depreciation and amortization expenses – segment totals		$	62,708		$	55,382		$	49,634
	Unallocated corporate depreciation expenses			1,096			1,018			1,660
	Consolidated depreciation and amortization expenses		$	63,804		$	56,400		$	51,294
	(a)	See Note 21 regarding business restructuring and asset impairment costs.
	(b)	Unallocated corporate expenses primarily comprise 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.
	(c)	The decline in unallocated corporate assets between 2013 and 2014 was primarily attributable to decreases in the balances of U.S. cash and cash equivalents, which are not allocated to segments. The increase in unallocated corporate assets between 2012 and 2013 was primarily attributable to increases in the balances of U.S. cash and cash equivalents and mutual fund investment assets, which are not allocated to segments.
Summary of company-wide geographic data	Below is certain Company-wide geographic data for the years ended December 31, 2014, 2013 and 2012:
	(In thousands)		2014			2013			2012
	Net sales (a)
	United States		$	1,146,405		$	1,103,181		$	1,076,222
	France (b)			183,896			221,971			298,158
	Poland (b)			175,862			122,215			19,588
	United Kingdom			103,696			104,470			103,523
	All other countries			317,354			328,949			306,246
	Total		$	1,927,213		$	1,880,786		$	1,803,737
	Long-lived assets (c)
	United States		$	360,921		$	330,799		$	246,118
	Germany			36,156			42,309			34,213
	Singapore			41,909			44,315			43,239
	Philippines			17,793			18,817			22,658
	Brazil			25,991			22,920			18,410
	United Kingdom			23,040			23,061			20,878
	All other countries			50,690			47,216			52,483
	Total		$	556,500		$	529,437		$	437,999
	(a)	Net sales are attributed to countries based on selling location.
	(b)	The 2012-to-2013 net sales increase for Poland and net sales decrease for France reflected the 2013 transfer of ownership of the Company’s European Polymer intangibles from the Company’s France subsidiary to its Poland subsidiary, which resulted in European Polymer sales being recognized in Poland instead of France.
	(c)	Includes net property, plant and equipment, goodwill and other intangible assets.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	Below is the computation of basic and diluted earnings per share for the years ended December 31, 2014, 2013 and 2012:
	(In thousands, except per share amounts)		2014		2013		2012
	Computation of Basic Earnings per Share
	Net income attributable to Stepan Company		$	57,101	$	72,828	$	79,396
	Deduct dividends on preferred stock			—		43		579
	Income applicable to common stock		$	57,101	$	72,785	$	78,817
	Weighted-average number of shares outstanding			22,758		22,621		21,273
	Basic earnings per share		$	2.51	$	3.22	$	3.71
	Computation of Diluted Earnings per Share
	Net income attributable to Stepan Company		$	57,101	$	72,828	$	79,396
	Weighted-average number of shares outstanding			22,758		22,621		21,273
	Add weighted-average net shares from assumed exercise of options (under treasury stock			148		215		392
	method) (1)
	Add weighted-average contingently issuable net shares related to performance stock awards (under treasury stock method)			─		─		12
	Add weighted-average unvested stock awards (under treasury stock method)			11		8		6
	Add weighted-average shares from assumed conversion of convertible preferred stock			─		80		1,047
	Weighted-average shares applicable to diluted			22,917		22,924		22,730
	earnings
	Diluted earnings per share		$	2.49	$	3.18	$	3.49
	-1	Options to purchase 99,044, 49,815 and 16,444 shares of common stock were not included in the computations of diluted earnings per share for the years ended December 31, 2014, 2013 and 2012, respectively. The options’ exercise prices were greater than the average market price for the common stock and the effect of the options on earnings per share would have been antidilutive.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Summary of Changes in Accumulated Other Comprehensive Income	Below is the change in the Company’s accumulated other comprehensive income (loss) (AOCI) balance by component (net of income taxes) for the years ended December 31, 2012, 2013 and 2014:
	(In thousands)		Foreign			Defined
			Currency			Benefit			Cash Flow
			Translation			Pension Plan			Hedge
			Adjustments			Adjustments			Adjustments			Total
	Balance at December 31, 2011		$	(9,086	)	$	-32,398		$	(1	)	$	(41,485	)
	Other comprehensive income before							)
	reclassifications			6,200			(5,387			116			929
	Amounts reclassified from AOCI			—			2,287			19			2,306
	Net current period other comprehensive income							)
				6,200			(3,100			135			3,235
	Balance at December 31, 2012		$	(2,886	)	$	(35,498	)	$	134		$	(38,250	)
	Other comprehensive income before				)						)
	reclassifications			(8,085			13,417			(32			5,300
	Amounts reclassified from AOCI			—			3,409			13			3,422
	Net current period other comprehensive income				)						)
				(8,085			16,826			(19			8,722
	Balance at December 31, 2013		$	(10,971	)	$	(18,672	)	$	115		$	(29,528	)
	Other comprehensive income before				)			)						)
	reclassifications			(31,943			(24,186			—			(56,129
	Amounts reclassified from AOCI			—			1,709			3			1,712
	Net current period other comprehensive income				)			)						)
				(31,943			(22,477			3			(54,417
	Balance at December 31, 2014		$	(42,914	)	$	(41,149	)	$	118		$	(83,945	)
Summary of Amounts Reclassified Out of Accumulated Other Comprehensive Income	Amounts reclassified out of AOCI for the three years ended December 31, 2014, 2013 and 2012, is displayed below:
	Amounts Reclassified from AOCI (a)
	(In thousands)											Affected Line Item in
												Consolidated
			2014			2013			2012			Statements of Income
	Amortization of defined pension items:
	Prior service cost		$	(20	)	$	(19	)	$	(18	)
	Actuarial loss			(2,727	)		(5,410	)		(3,632	)
	Transition obligation			–			(2	)		(18	)
			$	(2,747	)		(5,431	)		(3,668	)	Total before tax (b)
				1,038			2,022			1,381		Tax  benefit
			$	(1,709	)	$	(3,409	)	$	(2,287	)	Net of tax
	Gains and losses on cash flow hedges:
	Interest rate contracts		$	(20	)	$	(37	)	$	(27	)	Interest, net
	Foreign exchange contracts			10			10			—		Cost of sales
				(10	)		(27	)		(27	)	Total before tax
				7			14			8		Tax  benefit
			$	(3	)	$	(13	)	$	(19	)	Net of tax
	Total reclassifications for the period		$	(1,712	)	$	(3,422	)	$	(2,306	)	Net of tax
	·	Amounts in parentheses denote expense to statement of income.
	·	This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 13 for details regarding net periodic benefit costs for the Company’s U.S. and U.K. defined benefit plans).

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Summary of Assets Acquired and Liabilities Assumed	The following table summarizes the assets acquired and liabilities assumed:
	(Dollars in thousands)	June 1, 2013
	Assets:
	Inventory	$	9,002
	Property, plant and equipment		37,000
	Identifiable intangible assets		17,800
	Goodwill		4,642
	Total assets acquired	$	68,444
	Liabilities:
	Accrued expenses		232
	Net assets acquired	$	68,212
Summary of Pro Forma Financial Information	The following is pro forma financial information prepared under the assumption that the acquisition of the BMS North American polyester resins business occurred on January 1, 2012:
	Pro Forma Financial Information
	Unaudited
		Year Ended
		December 31
	(In thousands, except per share amounts)	2013		2012
	Net Sales	$	1,907,607	$	1,866,209
	Net Income Attributable to Stepan Company	$	73,609	$	80,353
	Net Income Per Common Share Attributable to Stepan Company:
	Basic	$	3.25	$	3.75
	Diluted	$	3.21	$	3.54

Business_Restructuring_and_Ass1

Business Restructuring and Asset Impairments (Tables)	12 Months Ended
	Dec. 31, 2014
Restructuring And Related Activities [Abstract]
Reconciliation of Restructuring Liability	Following is a reconciliation of the beginning and ending balances of the restructuring liability:
	(In thousands)	Severance
		Expense
	Restructuring liability at December 31, 2013	$	1,040
	Amounts paid		(420	)
	Foreign currency translation		(57	)
	Restructuring liability at December 31, 2014	$	563

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data
		2014
	Quarter	First			Second			Third			Fourth			Year
	Net Sales	$	477,442		$	504,111		$	491,429		$	454,231		$	1,927,213
	Gross Profit		63,024			71,589			65,099			49,851			249,563
	Operating Income		22,523			36,914			22,253			9,004			90,694
	Interest, net		(2,957	)		(3,021	)		(2,846	)		(2,617	)		(11,441	)
	Income Before Income Taxes		18,089			33,206			18,228			6,012			75,535
	Net Income		13,008			24,368			13,480			6,225			57,081
	Net Income Attributable to Stepan Company		13,018			24,353			13,491			6,239			57,101
	Per Diluted Share		0.57			1.06			0.59			0.27			2.49
		2013
	Quarter	First			Second			Third			Fourth			Year
	Net Sales	$	456,546		$	474,445		$	475,466		$	474,329		$	1,880,786
	Gross Profit		72,700			73,707			74,341			60,937			281,685
	Operating Income		28,294			35,869			31,085			13,905			109,153
	Interest, net		(2,179	)		(2,329	)		(2,987	)		(2,863	)		(10,358	)
	Income Before Income Taxes		25,273			32,200			27,847			10,310			95,630
	Net Income		18,997			22,654			20,149			10,537			72,337
	Net Income Attributable to Stepan Company		19,034			22,742			20,402			10,650			72,828
	Per Diluted Share		0.83			0.99			0.89			0.46			3.18

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Customer	Customer	Customer
	Subsidiary
Summary Of Significant Accounting Policy [Line Items]
Ownership percentage	80.00%
Cash and cash equivalents	$85,215,000	$133,347,000	$76,875,000	$84,099,000
Single customer comprised more than 10 percent of the Company's consolidated net sales	0	0	0
Bad debt allowance	4,625,000	719,000	314,000
Percentage of LIFO Inventory	67.00%	64.00%
Cost of maintenance and repairs	55,923,000	48,683,000	45,072,000
Total research and development expenses	27,236,000	28,782,000	28,032,000
Capitalized Environmental expenditures depreciation period	10 years
Indefinite-life intangible assets	0
Number of foreign subsidiaries	1
Natural Gas [Member]
Summary Of Significant Accounting Policy [Line Items]
Volume in derivative contract	1,600,000
Purchased Contract Price	6,558,000
Building [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	30 years
Building Improvements [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	15 years
Polymers [Member]
Summary Of Significant Accounting Policy [Line Items]
Bad debt allowance	2,388,000
Minimum [Member]
Summary Of Significant Accounting Policy [Line Items]
Percentage of Tax benefit recognized	50.00%
Minimum [Member] | Machinery and Equipment [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	10 years
Minimum [Member] | Furniture and Fixtures [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	5 years
Minimum [Member] | Vehicles [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	3 years
Minimum [Member] | Computers Equipment And Software [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	3 years
Maximum [Member] | Machinery and Equipment [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	15 years
Maximum [Member] | Furniture and Fixtures [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	10 years
Maximum [Member] | Vehicles [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	5 years
Maximum [Member] | Computers Equipment And Software [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	10 years
Demand Deposits [Member]
Summary Of Significant Accounting Policy [Line Items]
Cash and cash equivalents	8,400,000
Non U S Subsidiaries [Member]
Summary Of Significant Accounting Policy [Line Items]
Cash and cash equivalents	$76,800,000

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Allowance for Doubtful Accounts and Other Accounts Receivable Allowances (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance For Doubtful Accounts Receivable Rollforward
Allowance, balance at the beginning	$5,945	$5,533	$5,214
Provision charged to income	4,625	719	314
Accounts written off, net of recoveries	-559	-307	5
Allowance, balance at ending	$10,011	$5,945	$5,533

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Values and Related Carrying Values of Debt (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument Fair Value Carrying Value [Abstract]
Carrying value	$273,931	$270,623
Level 2 [Member]
Debt Instrument Fair Value Carrying Value [Abstract]
Fair value	$285,441	$276,069

Fair_Value_Measurements_Financ

Fair Value Measurements - Financial Assets and Liabilities Measured on a Recurring Basis at Fair Value (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financial assets and liabilities measured on a recurring basis at fair value
Mutual fund assets	$20,217	$18,305
Derivative assets:
Foreign currency contracts	73	74
Total assets at fair value	20,290	18,379
Derivative liabilities:
Foreign currency contracts	628	165
Interest rate contracts		20
Total liabilities at fair value		185
Level 1 [Member]
Financial assets and liabilities measured on a recurring basis at fair value
Mutual fund assets	20,217	18,305
Derivative assets:
Total assets at fair value	20,217	18,305
Level 2 [Member]
Derivative assets:
Foreign currency contracts	73	74
Total assets at fair value	73	74
Derivative liabilities:
Foreign currency contracts	628	165
Interest rate contracts		20
Total liabilities at fair value		$185

Derivative_Instruments_Additio

Derivative Instruments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$51,623,000	$20,289,000
Derivative foreign currency exchange contracts settlement date	1 month
Cash flow hedges [Member] | Interest rate contracts [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$0	$2,268,000

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Value of Goodwill and Other Intangible Assets (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill, Beginning Balance	$15,193	$10,666
Accumulated impairment loss, Beginning Balance	-3,467	-3,467
Goodwill net, Beginning Balance	11,726	7,199
Goodwill acquired		4,642
Foreign currency translation	-224	-115
Goodwill, Ending Balance	14,969	15,193
Accumulated impairment loss, Ending Balance	-3,467	-3,467
Goodwill net, Ending Balance	11,502	11,726
Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	9,107	9,246
Accumulated impairment loss, Beginning Balance	-3,467	-3,467
Goodwill net, Beginning Balance	5,640	5,779
Foreign currency translation	-82	-139
Goodwill, Ending Balance	9,025	9,107
Accumulated impairment loss, Ending Balance	-3,467	-3,467
Goodwill net, Ending Balance	5,558	5,640
Polymer Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	5,603	937
Goodwill net, Beginning Balance	5,603	937
Goodwill acquired		4,642
Foreign currency translation	-142	24
Goodwill, Ending Balance	5,461	5,603
Goodwill net, Ending Balance	5,461	5,603
Specialty Products Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance			483
Goodwill net, Beginning Balance			483
Goodwill, Ending Balance	483	483	483
Goodwill net, Ending Balance	$483	$483	$483

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment of Goodwill	$0	$0
Amortization of Intangible Assets, Total	$2,841,000	$2,832,000	$2,516,000

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets - Components of Other Intangible Assets and Changes in Gross Carrying Values (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	$27,389	$27,441
Other Finite-Lived Intangible Assets, Accumulated Amortization	6,586	3,772
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	6,947	6,947
Other Finite-Lived Intangible Assets, Accumulated Amortization	2,096	1,498
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	4,087	4,087
Other Finite-Lived Intangible Assets, Accumulated Amortization	748	345
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	8,082	8,094
Other Finite-Lived Intangible Assets, Accumulated Amortization	1,871	1,098
Know-how [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	8,273	8,313
Other Finite-Lived Intangible Assets, Accumulated Amortization	$1,871	$831

Goodwill_and_Other_Intangible_5

Goodwill and Other Intangible Assets - Estimated Amortization Expense for Identifiable Intangibles Assets (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Goodwill And Intangible Assets Disclosure [Abstract]
For year ended 12/31/15	$2,825
For year ended 12/31/16	2,681
For year ended 12/31/17	2,565
For year ended 12/31/18	2,565
For year ended 12/31/19	$2,565

Inventories_Composition_of_Inv

Inventories - Composition of Inventories (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Finished products	$126,157	$123,211
Raw materials	57,076	49,156
Total inventories	$183,233	$172,368

Inventories_Additional_Informa

Inventories - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
LIFO reserve	$34,340	$30,786

Debt_Debt_Detail

Debt - Debt (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Total debt	$273,931	$270,623
Less current maturities	27,034	35,377
Long-term debt	246,897	235,246
Unsecured private placement 3.86% note [Member]
Debt Instrument [Line Items]
Total debt	100,000	100,000
Debt instrument interest rate percentage	3.86%	3.86%
Maturity Dates	2019-2025	2019-2025
Unsecured private placement 4.86% note [Member]
Debt Instrument [Line Items]
Total debt	65,000	65,000
Debt instrument interest rate percentage	4.86%	4.86%
Maturity Dates	2017-2023	2017-2023
Unsecured private placement 5.88% note [Member]
Debt Instrument [Line Items]
Total debt	40,000	40,000
Debt instrument interest rate percentage	5.88%	5.88%
Maturity Dates	2016-2022	2016-2022
Unsecured private placement 5.69% note [Member]
Debt Instrument [Line Items]
Total debt	22,857	28,571
Debt instrument interest rate percentage	5.69%	5.69%
Maturity Dates	2015-2018	2015-2018
Unsecured private placement 6.86% note [Member]
Debt Instrument [Line Items]
Total debt	4,284	8,570
Debt instrument interest rate percentage	6.86%	6.86%
Maturity Dates	2015	2015
Unsecured U.S. bank debt [Member]
Debt Instrument [Line Items]
Total debt	20,000
Maturity Dates	2019	2019
Debt of foreign subsidiaries Unsecured bank debt, foreign currency [Member]
Debt Instrument [Line Items]
Total debt	12,043	19,488
Maturity Dates	2015	2015
Debt of foreign subsidiaries Unsecured bank term loan, foreign currency [Member]
Debt Instrument [Line Items]
Total debt	4,840
Maturity Dates	2021	2021
Debt of foreign subsidiaries Secured bank term loan, foreign currency [Member]
Debt Instrument [Line Items]
Total debt	2,723	5,843
Maturity Dates	2015	2015
Debt of foreign subsidiaries Secured bank debt, foreign currency [Member]
Debt Instrument [Line Items]
Total debt	1,638	2,153
Maturity Dates	2015	2015
Debt of foreign subsidiaries Unsecured bank debt, U.S dollars [Member]
Debt Instrument [Line Items]
Total debt	$546	$998
Maturity Dates	2015	2015

Debt_Additional_Information_De

Debt - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jul. 10, 2014
Debt Instrument [Line Items]
Total debt	$273,931,000	$270,623,000
Revolving credit agreement	125,000,000
Letters of Credit Outstanding	2,727,000
Debt Outstanding	20,000,000
Unused Revolving credit	102,273,000
Line of credit facility, Minimum maturity period	1 day
Line of credit facility, Maximum maturity period	180 days
Debt matures in 2016	12,723,000
Debt matures in 2015	27,034,000
Unrestricted retained earnings	88,684,000	148,467,000
Debt matures in 2017	21,405,000
Debt matures in 2018	21,406,000
Debt matures in 2019	49,977,000
Debt matures after 2019	141,386,000
Amount of repayments of long-term debt due in next year	12,808,000
Amount of repayments of foreign subsidiaries short-term debt due in next year	14,226,000
Philippine Subsidiary [Member]
Debt Instrument [Line Items]
Spread rate	1.38%
Short-term Debt	747,000
Multi Currency Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit agreement			125,000,000
Credit agreement expire period, before amendment	20-Sep-17
Credit agreement expire period, after amendment	10-Jul-19
Minimum [Member]
Debt Instrument [Line Items]
Facility fee percentage	0.15%
Minimum [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Spread rate	0.98%
Minimum [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Spread rate	0.00%
Maximum [Member]
Debt Instrument [Line Items]
Spread on Prime rate	0.53%
Facility fee percentage	0.35%
Maximum [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Spread rate	1.53%
Unsecured Private Placement Notes [Member]
Debt Instrument [Line Items]
Total debt	232,141,000
Unsecured Private Placement Notes [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument interest rate percentage	3.86%
Maturity Dates	12 years
Unsecured Private Placement Notes [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument interest rate percentage	6.86%
Maturity Dates	13 years
European Debt [Member]
Debt Instrument [Line Items]
Short-term Debt	11,842,000
European Debt [Member] | Short Term Borrowing Acquired In UK Based Rate [Member]
Debt Instrument [Line Items]
Spread rate	2.00%
Short term borrowing on UK base rate	1,638,000
European Debt [Member] | Bank Term Loan [Member]
Debt Instrument [Line Items]
Spread rate	1.30%
Short-term Debt	7,563,000
Debt matures in 2021	4,840,000
Loan maturity	2021
European Debt [Member] | Other Term Loan [Member]
Debt Instrument [Line Items]
Spread rate	1.08%
Loan maturity	2016
Fixed interest rate	2.15%
Debt matures in 2016	1,815,000
Debt matures in 2015	$908,000
European Debt [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread rate	0.30%
European Debt [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread rate	0.50%

Debt_Schedule_of_Net_Interest_

Debt - Schedule of Net Interest Expense (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest Income Expense Net [Abstract]
Interest expense									$12,542	$11,104	$9,998
Interest income									-262	-57	-112
Interest expense net of interest income									12,280	11,047	9,886
Capitalized interest									-839	-689	-287
Interest expense, net	$2,617	$2,846	$3,021	$2,957	$2,863	$2,987	$2,329	$2,179	$11,441	$10,358	$9,599

Leased_Properties_Additional_I

Leased Properties - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Leases [Abstract]
Total rental expense	$6,660,000	$6,280,000	$6,713,000

Leased_Properties_Consolidated

Leased Properties - Consolidated Company Minimum Future Rental Payments Under Operating Leases with Terms in Excess of One Year (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Leases [Abstract]
2015	$4,523
2016	3,522
2017	2,163
2018	1,866
2019	1,822
Subsequent to 2019	16,651
Total minimum future rental payments	$30,547

Other_Net_Other_Net_in_Consoli

Other, Net - Other Net in Consolidated Statements of Income (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Nonoperating Income Expense [Abstract]
Foreign exchange loss	($220)	($1,495)	($304)
Investment related income	1,269	1,055	173
Realized and unrealized gain on investments	241	2,611	1,460
Other, net	$1,290	$2,171	$1,329

Income_Taxes_Schedule_of_Provi

Income Taxes - Schedule of Provision for Taxes on Income and Other Related Income Before Taxes (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Federal
Current									$3,362	$9,744	$23,744
Deferred									4,338	-285	-525
State
Current									782	1,223	1,999
Deferred									643	-680	-537
Foreign
Current									9,004	12,067	10,158
Deferred									325	1,224	1,196
Total									18,454	23,293	36,035
Income before Taxes
Domestic									34,091	50,626	80,371
Foreign									41,444	45,004	35,351
Income Before Provision for Income Taxes	$6,012	$18,228	$33,206	$18,089	$10,310	$27,847	$32,200	$25,273	$75,535	$95,630	$115,722

Income_Taxes_Summary_of_Variat

Income Taxes - Summary of Variations Between the Effective and Statutory U.S. Federal Income Tax Rates (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Federal income tax provision at statutory tax rate	$26,437	$33,471	$40,503
State tax provision on income less applicable federal tax benefit	926	353	1,470
Foreign income taxed at different rates	-5,175	-2,509	-1,172
Repatriation of foreign earnings	83	146	24
Domestic production activities deduction	-312	-991	-1,446
Nontaxable foreign interest income	-2,435	-2,614	-2,690
Nontaxable biodiesel excise credit income	-130	-2,347
U.S. tax credits	-1,086	-2,209
Non-deductible expenses and other items, net	146	-7	-654
Total	$18,454	$23,293	$36,035
Percentage of Federal income tax provision at statutory tax rate	35.00%	35.00%	35.00%
Percentage of State tax provision on income less applicable federal tax benefit	1.20%	0.40%	1.30%
Percentage of Foreign income taxed at different rates	-6.90%	-2.60%	-1.00%
Percentage of Repatriation of foreign earnings	0.10%	0.20%
Percentage of Domestic production activities deduction	-0.40%	-1.00%	-1.20%
Percentage of Nontaxable foreign interest income	-3.20%	-2.70%	-2.30%
Percentage of Nontaxable biodiesel excise credit income	-0.20%	-2.50%
Percentage of U.S. tax credits	-1.40%	-2.30%
Percentage of Non-deductible expenses and other items, net	0.20%	-0.10%	-0.70%
Percentage of Total income tax provision	24.40%	24.40%	31.10%

Income_Taxes_Schedule_Showing_

Income Taxes - Schedule Showing Tax Effects of Significant Temporary Differences Representing Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Tax Liabilities:
Depreciation	($63,104)	($57,113)
Amortization of intangibles		-49
Unrealized foreign exchange loss	-838	-910
Other	-1,159	-823
Deferred Tax Liabilities, Gross	-65,101	-58,895
Deferred Tax Assets:
Pensions	18,775	5,640
Deferred revenue	1,650	3,058
Other accruals and reserves	13,230	12,061
Inventories	1,957	1,158
Legal and environmental accruals	9,505	6,594
Deferred compensation	15,636	20,510
Bad debt and rebate reserves	4,618	3,018
Subsidiaries net operating loss carryforwards	727	899
Tax credit carryforwards	2,064	915
Deferred Tax Assets, Gross	68,162	53,853
Valuation Allowance	-1,506	-1,302
Net Deferred Tax (Liabilities) Assets	1,555	-6,344
Reconciliation to Consolidated Balance Sheet:
Current deferred tax assets	15,364	12,637
Non-current deferred tax assets (in other non-current assets)	2,044	1,658
Current deferred tax liabilities (in accrued liabilities)	-49	-23
Non-current deferred tax liabilities	-15,804	-20,616
Net Deferred Tax (Liabilities) Assets	$1,555	($6,344)

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Undistributed earnings of foreign subsidiaries	$224,483	$194,148
Tax loss carryforwards	2,776	3,980
Tax credit carryforwards	2,064	915
Valuation Allowance	1,506	1,302
Unrecognized tax benefits	464	240	289	1,232
Unrecognized tax benefits that, if recognized, would impact effective tax rates	454	231	275
Recognition of interest and penalties accrued related to unrecognized tax benefits as income tax expense	6	9	444
Income tax liability for interest and penalties	38	32
Net tax benefit recognized under voluntary disclosure agreement			$688

Income_Taxes_Schedule_of_Recon

Income Taxes - Schedule of Reconciliations of Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, opening balance	$240	$289	$1,232
Gross increases – tax positions in prior period		27
Gross decreases – tax positions in prior period		-41	-569
Gross increases – current period tax positions	261	17	44
Foreign currency translation	-13	5	23
Lapse of statute of limitations	-24	-57	-441
Unrecognized tax benefits, ending balance	$464	$240	$289

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Aug. 09, 2013
Class Of Stock [Line Items]
Preferred stock redemption date	9-Aug-13
Preferred stock dividend rate		5.50%
Preferred stock outstanding		0	61,735
Number of Preferred shares converted		60,900
Number of common shares issued upon conversion of preferred stock		139,029
Preferred shares redeemed		835
Aggregate redemption price		$25.26
Treasury stock, shares	3,384,443	3,231,289
Treasury stock distributed under deferred compensation plan	3,658
Stock purchased to settle employees statutory withholding taxes relates to performance stock awards and deferred compensation distribution	2,179
Open Market Repurchases [Member]
Class Of Stock [Line Items]
Shares purchased during period	154,633
Price per share [Member]
Class Of Stock [Line Items]
Aggregate redemption price		$25
Accrued and Unpaid Dividends [Member]
Class Of Stock [Line Items]
Aggregate redemption price		$0.26

Stockbased_Compensation_Additi

Stock-based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock authorized for share based payment awards under 2011 Plan	2,600,000
Shares available for grant under the 2011 plan	1,971,353
Compensation expenses (income) charged against income	($69)	$2,783	$3,122
Income tax benefit (expense) recognized in the income statement for share-based compensation arrangements	-26	1,059	1,186
Proceeds from stock option exercises	1,754	3,977	4,473
Actual tax benefit recognized for the tax deductions from stock options exercise	640	3,440	7,237
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
Weighted-average grant-date fair values of options awarded	$23.77	$23.08	$15.73
Intrinsic values of options exercised	2,071	9,138	17,163
Unrecognized compensation cost	774
Weighted average period for amortization of unrecognized compensation cost	1 year
Actual tax benefit recognized for the tax deductions from stock options exercise	568	2,786	6,411
Stock Option [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period of expiration	10 years
Stock Option [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period of expiration	8 years
Performance Stock Award [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance stock awards vested	0
Stock Awards[Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	1,365
Weighted average period for amortization of unrecognized compensation cost	2 years
Weighted-average grant-date fair values of awards granted	$59.52	$60.75	$41
SARs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period of expiration	10 years
Vesting period	2 years
Unrecognized compensation cost	693
Weighted average period for amortization of unrecognized compensation cost	1 year 1 month 6 days
Weighted-average grant-date fair values of awards granted	$23.74	$23.12	$15.73
SARs liability	$1,457	$2,172

Stockbased_Compensation_Fair_V

Stock-based Compensation - Fair Value Assumptions for Stock Options (Detail) (Stock Option [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	1.77%	2.01%	2.10%
Expected volatility	42.04%	42.48%	43.19%
Expected term	7 years 3 months 18 days	7 years 4 months 24 days	7 years 4 months 24 days
Risk-free interest rate	2.18%	1.53%	1.41%

Stockbased_Compensation_Summar

Stock-based Compensation - Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Beginning Balance	505,112
Granted, Shares	53,175
Exercised, Shares	-67,029	-227,410	-582,730
Forfeited, Shares	-10,522
Shares, Ending Balance	480,736	505,112
Vested or expected to vest, Shares	480,736
Exercisable, Shares	384,457
Weighted Average Exercise Price, Beginning Balance	$30.80
Granted, Weighted Average Exercise Price	$61.69
Exercised, Weighted Average Exercise Price	$26.17
Forfeited, Weighted Average Exercise Price	$54.41
Weighted Average Exercise Price, Ending Balance	$34.35	$30.80
Vested or expected to vest, Weighted Average Exercise Price	$34.35
Exercisable, Weighted Average Exercise Price	$27.37
Weighted Average Remaining Contractual Term, Ending Balance	4 years 5 months 5 days
Vested or expected to vest, Weighted Average Remaining Contractual Term	4 years 5 months 5 days
Exercisable, Weighted Average Remaining Contractual Term	3 years 4 months 13 days
Aggregate Intrinsic Value, Ending Balance	$2,757
Vested or expected to vest, Aggregate Intrinsic Value	2,757
Exercisable, Aggregate Intrinsic Value	$4,885

Stockbased_Compensation_Summar1

Stock-based Compensation - Summary of Stock Award Activity (Detail) (Stock Awards[Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Awards[Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Beginning Balance	221,090
Granted, Shares	89,234
Forfeited, Shares	127,314
Shares, Ending Balance	183,010	221,090
Unvested Weighted Average Grant Date Fair Value, Beginning Balance	$48.75
Granted, Weighted Average Grant Date Fair Value	$59.52	$60.75	$41
Forfeited, Weighted Average Grant Date Fair Value	$43.12
Unvested Weighted Average Grant Date Fair Value, Ending Balance	$57.92	$48.75

Stockbased_Compensation_Summar2

Stock-based Compensation - Summary of SARs Activity (Detail) (SARs [Member], USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014
SARs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Beginning Balance	148,311
Granted, Shares	116,843
Forfeited, Shares	-33,972
Shares, Ending Balance	231,182
Weighted Average Exercise Price, Beginning Balance	$54.60
Granted, Weighted Average Exercise Price	$61.62
Forfeited, Weighted Average Exercise Price	$55.99
Weighted Average Exercise Price, Ending balance	$57.94
Weighted Average Remaining Contractual Term, Ending balance	8 years 4 months 24 days
Aggregate Intrinsic Value, Ending balance	($4,130)

Deferred_Compensation_Addition

Deferred Compensation - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Deferred compensation	($11,903)	$9,496	$10,252
Deferred compensation liability	$38,730	$51,543

Postretirement_Benefit_Plans_O

Postretirement Benefit Plans - Obligations and Funded Status (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	$144,508	$157,051
Interest cost	6,936	6,424	6,880
Actuarial (gain) loss	23,547	-14,142
Benefits paid	-5,584	-4,825
Benefit obligation at end of year	169,407	144,508	157,051
Fair value of plan assets at beginning of year	133,264	124,682
Actual return on plan assets	-2,929	13,225
Employer contributions	1,618	182
Fair value of plan assets at end of year	126,369	133,264	124,682
Over (Under) funded status at end of year	-43,038	-11,244
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	21,095	21,722
Interest cost	964	899	841
Actuarial (gain) loss	3,176	-1,365
Benefits paid	-822	-521
Foreign exchange impact	-1,430	360
Benefit obligation at end of year	22,983	21,095	21,722
Fair value of plan assets at beginning of year	22,204	18,390
Actual return on plan assets	1,902	2,840
Employer contributions	1,004	949
Foreign exchange impact	-1,430	546
Fair value of plan assets at end of year	22,858	22,204	18,390
Over (Under) funded status at end of year	($125)	$1,109

Postretirement_Benefit_Plans_S

Postretirement Benefit Plans - Schedule of Amounts Recognized in Balance Sheets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset		$818
Current liability	-185	-185
Non-current liability	-42,853	-11,877
Net amount recognized	-43,038	-11,244
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset		1,109
Non-current liability	-125
Net amount recognized	($125)	$1,109

Postretirement_Benefit_Plans_A

Postretirement Benefit Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	$60,114	$26,802
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	$4,724	$2,147

Postretirement_Benefit_Plans_A1

Postretirement Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 19, 2014	Feb. 20, 2013
Defined Benefit Plan Disclosure [Line Items]
Increase in benefit obligation	$9,500,000
Assets gains or losses added for prior year	80.00%
Assets gains or losses added for second preceding year	60.00%
Assets gains or losses added for third preceding year	40.00%
Assets gains or losses added for fourth preceding year	20.00%
Expected long-term rate of return on assets	7.75%
Balance of trust assets	1,741,000	1,849,000
Supplemental plan liability balances	1,776,000	1,899,000
Defined contribution plan expense	8,184,000	9,304,000	10,046,000
Commodities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for equities	2.00%
Expected long-term rate of return on assets	6.70%
U.S Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of fixed income assets in debt securities	20.00%
Common shares sold to the Company's ESOP trust				37,999	43,534
Expected payment related to unqualified plan	185,000
U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of premium estimated return for equities and properties to risk free rate	3.00%
Percentage of long term return in cash	4.00%
Company's expected contribution to qualified plan	950,000
Statutory Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan expense	145,000	1,999,000	711,000
Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for equities	34.00%
Expected long-term rate of return on assets	8.82%
Debt Securities [Member] | U.S Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for equities	35.00%
Real Estate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for equities	4.00%
Expected long-term rate of return on assets	7.40%
Employer Securities [Member] | U.S Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for equities	25.00%
U.S. and international equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on assets	4.73%
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation at end of year	169,407,000
Percentage of equities within the pooled pension fund	41.00%
Expected long-term rate of return on assets	7.75%	7.75%	7.75%
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation at end of year	$22,983,000
Percentage of equities within the pooled pension fund	23.00%
Expected long-term rate of return on assets	5.84%	5.25%	5.46%
Europe [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of equities within the pooled pension fund	20.00%
Other Regions [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of equities within the pooled pension fund	16.00%

Postretirement_Benefit_Plans_I

Postretirement Benefit Plans - Information for Pension Plans with Projected Benefit Obligations in Excess of Plan Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Projected benefit obligation	$169,407	$113,865
Accumulated benefit obligation	169,407	113,865
Fair value of plan assets	126,369	101,803
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Projected benefit obligation	22,983
Accumulated benefit obligation	22,983
Fair value of plan assets	$22,858

Postretirement_Benefit_Plans_C

Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Interest cost	$6,936	$6,424	$6,880
Expected return on plan assets	-9,523	-8,828	-8,423
Amortization of net actuarial loss	2,687	5,109	3,573
Net periodic benefit cost	100	2,705	2,030
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Interest cost	964	899	841
Expected return on plan assets	-1,303	-941	-888
Amortization of net actuarial loss		288	49
Net periodic benefit cost	($339)	$246	$2

Postretirement_Benefit_Plans_O1

Postretirement Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial (gain) loss	$35,999	($18,539)	$4,622
Amortization of net actuarial loss	-2,687	-5,109	-3,573
Total recognized in other comprehensive income	33,312	-23,648	1,049
Total recognized in net periodic benefit cost and other comprehensive income	33,412	-20,943	3,079
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial (gain) loss	2,577	-3,264	3,111
Amortization of net actuarial loss		-288	-49
Total recognized in other comprehensive income	2,577	-3,552	3,062
Total recognized in net periodic benefit cost and other comprehensive income	$2,238	($3,306)	$3,064

Postretirement_Benefit_Plans_E

Postretirement Benefit Plans - Estimated Amounts Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	$4,597
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	$184

Postretirement_Benefit_Plans_E1

Postretirement Benefit Plans - Estimated Future Benefit Payments (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2015	$6,153
2016	6,714
2017	7,322
2018	7,821
2019	8,283
2020-2024	48,207
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2015	558
2016	584
2017	620
2018	631
2019	639
2020-2024	$3,721

Postretirement_Benefit_Plans_W

Postretirement Benefit Plans - Weighted-Average Assumptions Used To Determine Benefit Obligations (Detail)	Dec. 31, 2014	Dec. 31, 2013
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.09%	4.87%
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	3.50%	4.60%

Postretirement_Benefit_Plans_T1

Postretirement Benefit Plans - The Weighted Average Assumptions Used to Determine Net Periodic Benefit Costs (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Expected long-term return on plan assets	7.75%
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.87%	4.17%	5.06%
Expected long-term return on plan assets	7.75%	7.75%	7.75%
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.60%	4.30%	4.90%
Expected long-term return on plan assets	5.84%	5.25%	5.46%

Postretirement_Benefit_Plans_C1

Postretirement Benefit Plans - Company's Asset Allocations for its U.S. Pension Plans by Asset Category (Detail) (United States [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]
Total	$126,369	$133,264	$124,682
Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	3,352	3,116
Commodities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	2,023	912
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	76,896	91,810
Level 1 [Member] | Commodities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	2,023	912
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	49,473	41,454
Level 2 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	3,352	3,116
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,963	2,471
Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,963	2,471
U.S. Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	34,885	32,567
U.S. Equities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	34,885	32,567
Non-U.S. Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	12,478	11,892
Non-U.S. Equities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	12,478	11,892
Employer Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	21,575	37,823
Employer Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	21,575	37,823
Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	68,938	82,282
Equities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	68,938	82,282
U.S. Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	27,676	24,733
U.S. Corporate Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	27,676	24,733
U.S. Government and Agency Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	10,677	9,101
U.S. Government and Agency Bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	350	2,526
U.S. Government and Agency Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	10,327	6,575
Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	6,155	4,559
Other Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	6,155	4,559
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	47,860	41,509
Debt Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	350	2,526
Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	47,510	38,983
Real Estate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	5,585	6,090
Real Estate Fund [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	$5,585	$6,090

Postretirement_Benefit_Plans_C2

Postretirement Benefit Plans - Company's Asset Allocations for its U.K. Pension Plans by Asset Category (Detail) (United Kingdom [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]
Total	$22,858	$22,204	$18,390
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,176	412
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	19,441	19,366
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	2,241	2,426
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,176	412
Cash [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,176	412
Pooled Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	15,322	15,397
Pooled Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	15,322	15,397
Pooled Fixed Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	3,642	3,550
Pooled Fixed Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	3,642	3,550
Real Estate Pooled Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	477	419
Real Estate Pooled Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	477	419
Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	2,241	2,426
Insurance Contracts [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	$2,241	$2,426

Postretirement_Benefit_Plans_F

Postretirement Benefit Plans - Fair Value Changes Within Asset Categories for which Fair Value Measurements Use Significant Unobservable Inputs Level 3 (Detail) (Insurance Contracts [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Insurance Contracts [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$2,426	$2,437
Sale proceeds (benefit payments)	-178	-175
Change in unrealized gain	135	120
Foreign exchange impact	-142	44
Ending balance	$2,241	$2,426

Postretirement_Benefit_Plans_D

Postretirement Benefit Plans - Defined Contribution Plan Expenses for the Company's Retirement Savings Plans and Profit Sharing Plan (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Total	$8,184	$9,304	$10,046
Retirement Savings Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Total	4,565	4,500	4,284
Profit Sharing Plan [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans [Line Items]
Total	$3,619	$4,804	$5,762

Accrued_Liabilities_Statement_

Accrued Liabilities - Statement of composition of Accrued Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]
Accrued payroll and benefits	$28,060	$39,722
Accrued customer rebates	17,395	15,514
Other accrued liabilities	20,041	21,103
Total accrued liabilities	$65,496	$76,339

Other_NonCurrent_Liabilities_S

Other Non-Current Liabilities - Statement of Composition of Other Non Current Liablities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other Liabilities Disclosure [Abstract]
Deferred revenue	$3,318	$4,045
Environmental and legal matters	20,583	13,133
Deferred compensation liability	37,790	50,728
Pension liability	45,738	14,923
Other non-current liabilities	5,427	5,777
Total other non-current liabilities	$112,856	$88,606

Contingencies_Additional_Infor

Contingencies - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2014
		States
Site Contingency [Line Items]
Environmental and legal losses, minimum	$21,900,000	$21,900,000
Environmental and legal losses, maximum	41,800,000	41,800,000
Accrued liability for losses	22,000,000	22,000,000	14,700,000
Cash outlays related to legal and environmental matters		1,200,000	2,400,000
Accrual for environmental loss contingencies, increase (decrease) for revision in estimates		7,100,000
Number of states examining company unclaimed property records		7
Liability for unpaid claim and claim adjustment expense, claims paid	3,475,000
Maywood Site [Member]
Site Contingency [Line Items]
Accrual for environmental loss contingencies, increase (decrease) for revision in estimates				7,100,000
Wilmington Site [Member]
Site Contingency [Line Items]
Contribution for future response costs		5.00%
Payment of environmental response costs		$2,300,000

Segment_Reporting_Additional_I

Segment Reporting - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014
	Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment_Reporting_Operating_Se

Segment Reporting - Operating Segment (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$454,231	$491,429	$504,111	$477,442	$474,329	$475,466	$474,445	$456,546	$1,927,213	[1]	$1,880,786	[1]	$1,803,737	[1]
Operating income	9,004	22,253	36,914	22,523	13,905	31,085	35,869	28,294	90,694		109,153		128,716
Assets	1,162,014				1,167,202				1,162,014		1,167,202		985,478
Capital expenditures									101,819		92,865		83,159
Depreciation and amortization expenses									63,804		56,400		51,294
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									1,927,213		1,880,786		1,803,737
Operating income									131,955		165,639		178,963
Assets	1,129,905				1,070,949				1,129,905		1,070,949		950,714
Capital expenditures									98,823		91,440		81,317
Depreciation and amortization expenses									62,708		55,382		49,634
Surfactants [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									1,296,638		1,317,164		1,305,800
Operating income									60,778		100,201		118,591
Assets	741,677				710,521				741,677		710,521		692,891
Capital expenditures									70,796		66,266		56,236
Depreciation and amortization expenses									41,483		36,400		34,036
Polymers [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									550,966		483,361		423,959
Operating income									60,690		54,536		48,130
Assets	320,640				292,015				320,640		292,015		199,013
Capital expenditures									22,409		18,804		19,266
Depreciation and amortization expenses									18,433		16,351		13,328
Specialty Products [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									79,609		80,261		73,978
Operating income									10,487		10,902		12,242
Assets	67,588				68,413				67,588		68,413		58,810
Capital expenditures									5,618		6,370		5,815
Depreciation and amortization expenses									$2,792		$2,631		$2,270
[1]	Net sales are attributed to countries based on selling location.

Segment_Reporting_Reconciliati

Segment Reporting - Reconciliation of Segment Information to Consolidated Financial Statements (Detail) (USD $)	3 Months Ended										12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Operating income	$9,004		$22,253	$36,914	$22,523	$13,905		$31,085	$35,869	$28,294	$90,694		$109,153		$128,716
Business restructuring and asset impairments											-4,009	[1]	-1,040	[1]
Unallocated corporate expenses											-37,252	[2]	-55,446	[2]	-50,247	[2]
Interest expense, net											-11,441		-10,358		-9,599
Loss from equity in joint ventures											-5,008		-5,336		-4,724
Other, net											1,290		2,171		1,329
Income Before Provision for Income Taxes	6,012		18,228	33,206	18,089	10,310		27,847	32,200	25,273	75,535		95,630		115,722
Assets	1,162,014					1,167,202					1,162,014		1,167,202		985,478
Unallocated corporate assets	32,109	[3]				96,253	[3]				32,109	[3]	96,253	[3]	34,764	[3]
Capital expenditures											101,819		92,865		83,159
Unallocated corporate expenditures											2,996		1,425		1,842
Depreciation and amortization											63,804		56,400		51,294
Unallocated corporate depreciation expenses											1,096		1,018		1,660
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income											131,955		165,639		178,963
Assets	1,129,905					1,070,949					1,129,905		1,070,949		950,714
Capital expenditures											98,823		91,440		81,317
Depreciation and amortization											$62,708		$55,382		$49,634
[1]	See Note 21 regarding business restructuring and asset impairment costs.
[2]	Unallocated corporate expenses primarily comprise 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.
[3]	The decline in unallocated corporate assets between 2013 and 2014 was primarily attributable to decreases in the balances of U.S. cash and cash equivalents, which are not allocated to segments. The increase in unallocated corporate assets between 2012 and 2013 was primarily attributable to increases in the balances of U.S. cash and cash equivalents and mutual fund investment assets, which are not allocated to segments.

Segment_Reporting_Summary_of_C

Segment Reporting - Summary of Company Wide Geographic Data (Detail) (USD $)

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Schedule Of Geographical Segments [Line Items]

Net sales

$454,231

$491,429

$504,111

$477,442

$474,329

$475,466

$474,445

$456,546

$1,927,213

[1]

$1,880,786

[1]

$1,803,737

[1]

Long-lived assets

556,500

[2]

529,437

[2]

556,500

[2]

529,437

[2]

437,999

[2]

United States [Member]

Schedule Of Geographical Segments [Line Items]

Net sales

1,146,405

[1]

1,103,181

[1]

1,076,222

[1]

Long-lived assets

360,921

[2]

330,799

[2]

360,921

[2]

330,799

[2]

246,118

[2]

France [Member]

Schedule Of Geographical Segments [Line Items]

Net sales

183,896

[1],[3]

221,971

[1],[3]

298,158

[1],[3]

Poland [Member]

Schedule Of Geographical Segments [Line Items]

Net sales

175,862

[1],[3]

122,215

[1],[3]

19,588

[1],[3]

United Kingdom [Member]

Schedule Of Geographical Segments [Line Items]

Net sales

103,696

[1]

104,470

[1]

103,523

[1]

Long-lived assets

23,040

[2]

23,061

[2]

23,040

[2]

23,061

[2]

20,878

[2]

All Other Countries [Member]

Schedule Of Geographical Segments [Line Items]

Net sales

317,354

[1]

328,949

[1]

306,246

[1]

Long-lived assets

50,690

[2]

47,216

[2]

50,690

[2]

47,216

[2]

52,483

[2]

Germany [Member]

Schedule Of Geographical Segments [Line Items]

Long-lived assets

36,156

[2]

42,309

[2]

36,156

[2]

42,309

[2]

34,213

[2]

Singapore [Member]

Schedule Of Geographical Segments [Line Items]

Long-lived assets

41,909

[2]

44,315

[2]

41,909

[2]

44,315

[2]

43,239

[2]

Philippines [Member]

Schedule Of Geographical Segments [Line Items]

Long-lived assets

17,793

[2]

18,817

[2]

17,793

[2]

18,817

[2]

22,658

[2]

Brazil [Member]

Schedule Of Geographical Segments [Line Items]

Long-lived assets

$25,991

[2]

$22,920

[2]

$25,991

[2]

$22,920

[2]

$18,410

[2]

[1]

Net sales are attributed to countries based on selling location.

[2]

Includes net property, plant and equipment, goodwill and other intangible assets.

[3]

The 2012-to-2013 net sales increase for Poland and net sales decrease for France reflected the 2013 transfer of ownership of the Company’s European Polymer intangibles from the Company’s France subsidiary to its Poland subsidiary, which resulted in European Polymer sales being recognized in Poland instead of France.

Earnings_Per_Share_Computation

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Computation of Basic Earnings per Share
Net income attributable to Stepan Company	$6,239	$13,491	$24,353	$13,018	$10,650	$20,402	$22,742	$19,034	$57,101		$72,828		$79,396
Deduct dividends on preferred stock											43		579
Income applicable to common stock									57,101		72,785		78,817
Weighted-average number of shares outstanding									22,758		22,621		21,273
Basic earnings per share									$2.51		$3.22		$3.71
Computation of Diluted Earnings per Share
Net income attributable to Stepan Company									$57,101		$72,828		$79,396
Weighted-average number of shares outstanding									22,758		22,621		21,273
Add weighted-average net shares from assumed exercise of options (under treasury stock method)									148	[1]	215	[1]	392	[1]
Add weighted-average contingently issuable net shares related to performance stock awards (under treasury stock method)													12
Add weighted-average unvested stock awards (under treasury stock method)									11		8		6
Add weighted-average shares from assumed conversion of convertible preferred stock											80		1,047
Weighted-average shares applicable to diluted earnings									22,917		22,924		22,730
Diluted earnings per share	$0.27	$0.59	$1.06	$0.57	$0.46	$0.89	$0.99	$0.83	$2.49		$3.18		$3.49
[1]	Options to purchase 99,044, 49,815 and 16,444 shares of common stock were not included in the computations of diluted earnings per share for the years ended December 31, 2014, 2013 and 2012, respectively. The options’ exercise prices were greater than the average market price for the common stock and the effect of the options on earnings per share would have been antidilutive.

Earnings_Per_Share_Computation1

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Options to purchase shares of common stock not included in the computations of diluted earnings per share	99,044	49,815	16,444

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), beginning balance	($29,528)	($38,250)	($41,485)
Other comprehensive income before reclassifications	-56,129	5,300	929
Amounts reclassified from AOCI	1,712	3,422	2,306
Net current period other comprehensive income	-54,417	8,722	3,235
Accumulated Other Comprehensive Income (Loss), ending balance	-83,945	-29,528	-38,250
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), beginning balance	-10,971	-2,886	-9,086
Other comprehensive income before reclassifications	-31,943	-8,085	6,200
Net current period other comprehensive income	-31,943	-8,085	6,200
Accumulated Other Comprehensive Income (Loss), ending balance	-42,914	-10,971	-2,886
Defined Benefit Pension Plan Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), beginning balance	-18,672	-35,498	-32,398
Other comprehensive income before reclassifications	-24,186	13,417	-5,387
Amounts reclassified from AOCI	1,709	3,409	2,287
Net current period other comprehensive income	-22,477	16,826	-3,100
Accumulated Other Comprehensive Income (Loss), ending balance	-41,149	-18,672	-35,498
Cash Flow Hedge Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss), beginning balance	115	134	-1
Other comprehensive income before reclassifications		-32	116
Amounts reclassified from AOCI	3	13	19
Net current period other comprehensive income	3	-19	135
Accumulated Other Comprehensive Income (Loss), ending balance	$118	$115	$134

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income (Loss) - Summary of Amounts Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	($18,454)		($23,293)		($36,035)
Income applicable to common stock	57,101		72,785		78,817
Defined Benefit Pension Plan Adjustments [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Prior service cost	-20	[1]	-19	[1]	-18	[1]
Actuarial loss	-2,727	[1]	-5,410	[1]	-3,632	[1]
Transition obligation			-2	[1]	-18	[1]
Total before tax	-2,747	[1],[2]	-5,431	[1],[2]	-3,668	[1],[2]
Tax benefit	1,038	[1]	2,022	[1]	1,381	[1]
Income applicable to common stock	-1,709	[1]	-3,409	[1]	-2,287	[1]
Cash Flow Hedges [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total before tax	-10	[1]	-27	[1]	-27	[1]
Tax benefit	7	[1]	14	[1]	8	[1]
Income applicable to common stock	-3	[1]	-13	[1]	-19	[1]
Cash Flow Hedges [Member] | Interest rate contracts [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest, net	-20	[1]	-37	[1]	-27	[1]
Cash Flow Hedges [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	10	[1]	10	[1]
Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income applicable to common stock	($1,712)	[1]	($3,422)	[1]	($2,306)	[1]
[1]	Amounts in parentheses denote expense to statement of income.
[2]	This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 13 for details regarding net periodic benefit costs for the Company’s U.S. and U.K. defined benefit plans).

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	6 Months Ended	0 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 01, 2013	Dec. 31, 2013	Dec. 31, 2014	Jul. 15, 2014
		T			T
Business Acquisition [Line Items]
Private placement loan	$100,000,000
Procter and Gamble Company [Member] | Brazil [Member]
Business Acquisition [Line Items]
Capacity of production facility purchased in connection with acquisition					30,000
Bayer Material Science [Member]
Business Acquisition [Line Items]
Capacity of production facility purchased in connection with acquisition		21,000
Acquisition purchase price		68,212,000
Business acquisition cash paid		61,067,000
Business acquisition consideration payable for inventory			7,145,000
Acquisition-related costs incurred			270,000
Identifiable intangible assets		17,800,000
Bayer Material Science [Member] | Acquisition Related Expenses [Member]
Business Acquisition [Line Items]
Nonrecurring adjustments to pro forma net income			270,000
Bayer Material Science [Member] | Fair Value Adjustment to Acquisition Date Inventory [Member]
Business Acquisition [Line Items]
Nonrecurring adjustments to pro forma net income			558,000
Bayer Material Science [Member] | Know-how [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		7,900,000
Amortization periods for the identifiable intangible assets at the time of acquisition				8 years
Bayer Material Science [Member] | Trademark and Trade Name [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		3,800,000
Amortization periods for the identifiable intangible assets at the time of acquisition				11 years
Bayer Material Science [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		$6,100,000
Amortization periods for the identifiable intangible assets at the time of acquisition				12 years

Acquisitions_Summary_of_Assets

Acquisitions - Summary of Assets Acquired and Liabilities Assumed (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 01, 2013
In Thousands, unless otherwise specified
Assets:
Goodwill	$11,502	$11,726	$7,199
Bayer Material Science [Member]
Assets:
Inventory				9,002
Property, plant and equipment				37,000
Identifiable intangible assets				17,800
Goodwill				4,642
Total assets acquired				68,444
Liabilities:
Accrued expenses				232
Net assets acquired				$68,212

Acquisitions_Summary_of_Pro_Fo

Acquisitions - Summary of Pro Forma Financial Information (Detail) (Bayer Material Science [Member], USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Bayer Material Science [Member]
Business Acquisition Pro Forma Information [Line Items]
Net Sales	$1,907,607	$1,866,209
Net Income Attributable to Stepan Company	$73,609	$80,353
Net Income Per Common Share Attributable to Stepan Company:
Basic	$3.25	$3.75
Diluted	$3.21	$3.54

Business_Restructuring_and_Ass2

Business Restructuring and Asset Impairments - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended		3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2013
		Employees	Employees
Restructuring Cost And Reserve [Line Items]
Number of employees accepting voluntary termination incentive			13
Restructuring charges against income	$1,722		$1,722
Asset impairment charges	2,287		2,287
Number of North American positions eliminated		16
Accelerated depreciation expenses			1,825	296
Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charge for estimated severance expense related to an approved plan					1,040
Asia Surfactants Operations [Member]
Restructuring Cost And Reserve [Line Items]
Asset impairment charges	1,316
North American Surfactants Operations [Member]
Restructuring Cost And Reserve [Line Items]
Asset impairment charges	714
European Surfactants Operations [Member]
Restructuring Cost And Reserve [Line Items]
Asset impairment charges	$257

Business_Restructuring_and_Ass3

Business Restructuring and Asset Impairments - Reconciliation of Restructuring Liability (Detail) (Severance Expense [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Severance Expense [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring liability at Beginning Balance	$1,040
Amounts paid	-420
Foreign currency translation	-57
Restructuring liability at Ending Balance	$563

Insurance_Recovery_Additional_

Insurance Recovery - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Insurance Recovery For Business Interruption [Abstract]
Insurance recovery received for business interruption losses	$3,730	$1,188

Purchase_of_the_Remaining_Inte1

Purchase of the Remaining Interest in Stepan Philippines Inc - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 22, 2012	Dec. 31, 2012
Minority Interest [Line Items]
Percentage of company's ownership, before purchasing the interest in Stepan Philippines	88.80%
Percentage of company's ownership, after purchasing the interest in Stepan Philippines	100.00%
Purchase of remaining non controlling interest of Stepan Philippines Inc.	$2,000	($2,000)
Reclassification of cumulative translation adjustments (gains) to AOCI	197
Additional Paid-in Capital [Member]
Minority Interest [Line Items]
Purchase of remaining non controlling interest of Stepan Philippines Inc.	$551	$551

Statement_of_Cash_Flows_Noncas1

Statement of Cash Flows - Noncash Investing and Financing Activities - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Cash Flow Elements [Abstract]
Value of shares tendered for stock options exercised		$92,000	$8,400,000
Shares tendered for stock options exercised	0	1,562	176,114
Shares issued related to the Company's performance stock award plan	0	48,973	84,568
Value of shares issued related to Company's performance stock award plan		2,999,000	3,659,000
Noncash investing activities incurred for fixed asset acquisitions	$17,797,000	$11,772,000	$10,467,000

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (J6 Polymers, LLC [Member], USD $)	1 Months Ended
	Jan. 31, 2015	Mar. 31, 2015
Forecast [Member] | Minimum [Member]
Subsequent Event [Line Items]
Company's expectation of pretax gain from the kits sales		$2,500,000
Forecast [Member] | Maximum [Member]
Subsequent Event [Line Items]
Company's expectation of pretax gain from the kits sales		3,000,000
Polyurethane Systems Product Lines [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Net sales	$2,800,000

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net Sales	$454,231	$491,429	$504,111	$477,442	$474,329	$475,466	$474,445	$456,546	$1,927,213	[1]	$1,880,786	[1]	$1,803,737	[1]
Gross Profit	49,851	65,099	71,589	63,024	60,937	74,341	73,707	72,700	249,563		281,685		291,553
Operating Income	9,004	22,253	36,914	22,523	13,905	31,085	35,869	28,294	90,694		109,153		128,716
Interest, net	-2,617	-2,846	-3,021	-2,957	-2,863	-2,987	-2,329	-2,179	-11,441		-10,358		-9,599
Income Before Income Taxes	6,012	18,228	33,206	18,089	10,310	27,847	32,200	25,273	75,535		95,630		115,722
Net Income	6,225	13,480	24,368	13,008	10,537	20,149	22,654	18,997	57,081		72,337		79,687
Net Income Attributable to Stepan Company	$6,239	$13,491	$24,353	$13,018	$10,650	$20,402	$22,742	$19,034	$57,101		$72,828		$79,396
Diluted earnings per share	$0.27	$0.59	$1.06	$0.57	$0.46	$0.89	$0.99	$0.83	$2.49		$3.18		$3.49
[1]	Net sales are attributed to countries based on selling location.