ADTRAN (ADTN) 10-Q 4 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 20, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Trading Symbol	ADTN
Entity Registrant Name	ADTRAN INC
Entity Central Index Key	926,282
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		49,560,245

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 83,687	$ 73,439
Short-term investments	42,081	46,919
Accounts receivable, less allowance for doubtful accounts of $21 and $136 at September 30, 2015 and December 31, 2014, respectively	86,176	88,502
Other receivables	20,858	33,295
Inventory, net	100,705	86,710
Prepaid expenses	5,935	5,129
Deferred tax assets, net	17,517	17,095
Total Current Assets	356,959	351,089
Property, plant and equipment, net	73,656	74,828
Deferred tax assets, net	23,341	17,694
Goodwill	3,492	3,492
Other assets	9,893	10,942
Long-term investments	204,513	280,649
Total Assets	671,854	738,694
Current Liabilities
Accounts payable	69,372	56,414
Unearned revenue	16,484	22,762
Accrued expenses	13,427	11,077
Accrued wages and benefits	14,842	13,855
Income tax payable, net	12,923	14,901
Total Current Liabilities	127,048	119,009
Non-current unearned revenue	8,685	10,948
Other non-current liabilities	29,680	30,924
Bonds payable	28,800	28,800
Total Liabilities	$ 194,213	$ 189,681
Commitments and contingencies (see Note 14)
Stockholders' Equity
Common stock, par value $0.01 per share; 200,000 shares authorized; 79,652 shares issued and 49,560 shares outstanding at September 30, 2015 and 79,652 shares issued and 53,431 shares outstanding at December 31, 2014	$ 797	$ 797
Additional paid-in capital	246,577	241,829
Accumulated other comprehensive loss	(10,238)	(75)
Retained earnings	905,928	907,751
Less treasury stock at cost: 30,092 and 26,221 shares at September 30, 2015 and December 31, 2014, respectively	(665,423)	(601,289)
Total Stockholders' Equity	477,641	549,013
Total Liabilities and Stockholders' Equity	$ 671,854	$ 738,694

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 21	$ 136
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	79,652,000	79,652,000
Common stock, shares outstanding	49,560,000	53,431,000
Treasury stock, shares	30,092,000	26,221,000

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Sales	$ 158,078	$ 162,892	$ 461,051	$ 486,025
Cost of sales	87,429	84,635	256,593	243,181
Gross Profit	70,649	78,257	204,458	242,844
Selling, general and administrative expenses	30,016	32,438	93,203	100,165
Research and development expenses	32,561	33,324	100,576	99,547
Operating Income	8,072	12,495	10,679	43,132
Interest and dividend income	839	992	2,680	3,340
Interest expense	(151)	(150)	(448)	(525)
Net realized investment gain	2,060	2,687	8,430	7,219
Other income (expense), net	52	(963)	(848)	(1,615)
Income before provision for income taxes	10,872	15,061	20,493	51,551
Provision for income taxes	(3,805)	(3,735)	(7,565)	(16,223)
Net Income	$ 7,067	$ 11,326	$ 12,928	$ 35,328
Weighted average shares outstanding - basic	49,862	54,521	51,682	55,552
Weighted average shares outstanding - diluted	49,927	54,824	51,792	55,976
Earnings per common share - basic	$ 0.14	$ 0.21	$ 0.25	$ 0.64
Earnings per common share - diluted	0.14	0.21	0.25	0.63
Dividend per share	$ 0.09	$ 0.09	$ 0.27	$ 0.27

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 7,067	$ 11,326	$ 12,928	$ 35,328
Other Comprehensive Income (Loss), net of tax:
Net unrealized losses on available-for-sale securities	(4,291)	(3,148)	(6,577)	(2,850)
Defined benefit plan adjustments	71		211
Foreign currency translation	(1,351)	(2,568)	(3,797)	(2,182)
Other Comprehensive income (loss), net of tax	(5,571)	(5,716)	(10,163)	(5,032)
Comprehensive Income, net of tax	$ 1,496	$ 5,610	$ 2,765	$ 30,296

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net Income	$ 12,928	$ 35,328
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,765	11,127
Amortization of net premium on available-for-sale investments	2,085	3,363
Net realized gain on long-term investments	(8,430)	(7,219)
Net loss on disposal of property, plant and equipment	189	109
Stock-based compensation expense	4,788	6,296
Deferred income taxes	(2,332)	(122)
Tax benefit from stock option exercises	(40)	71
Excess tax benefits from stock-based compensation arrangements	(3)	(53)
Changes in operating assets and liabilities:
Accounts receivable, net	843	(15,807)
Other receivables	10,532	(10,726)
Inventory	(14,945)	2,413
Prepaid expenses and other assets	(1,665)	(4,095)
Accounts payable	13,687	3,563
Accrued expenses and other liabilities	(3,996)	7,507
Income tax payable, net	(1,137)	9,265
Net cash provided by operating activities	23,269	41,020
Cash flows from investing activities:
Purchases of property, plant and equipment	(7,843)	(8,162)
Proceeds from disposals of property, plant and equipment	122	1
Proceeds from sales and maturities of available-for-sale investments	189,728	187,013
Purchases of available-for-sale investments	(113,227)	(127,074)
Net cash provided by investing activities	68,780	51,778
Cash flows from financing activities:
Proceeds from stock option exercises	907	2,311
Purchases of treasury stock	(65,808)	(62,144)
Dividend payments	(13,989)	(15,060)
Payments on long-term debt		(16,500)
Excess tax benefits from stock-based compensation arrangements	3	53
Net cash used in financing activities	(78,887)	(91,340)
Net increase in cash and cash equivalents	13,162	1,458
Effect of exchange rate changes	(2,914)	(1,341)
Cash and cash equivalents, beginning of period	73,439	58,298
Cash and cash equivalents, end of period	83,687	58,415
Supplemental disclosure of non-cash investing activities:
Purchases of property, plant and equipment included in accounts payable	$ 1,303	$ 598

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited consolidated financial statements of ADTRAN ® In the opinion of management, all adjustments necessary to fairly state these interim statements have been recorded and are of a normal and recurring nature. The results of operations for an interim period are not necessarily indicative of the results for the full year. The interim statements should be read in conjunction with the financial statements and notes thereto included in ADTRAN’s Annual Report on Form 10-K for the year ended December 31, 2014, filed on February 24, 2015 with the SEC. Changes in Classifications We reclassified $2.3 million from other receivables to accounts receivable at December 31, 2014 to conform to the current period presentation. Out of Period Adjustment In connection with the preparation of our Condensed Consolidated Financial Statements, we recorded corrections of certain out of period, immaterial misstatements that occurred in prior periods, the most significant of which resulted in an increase in Other Expense of $1.3 million in the first quarter of 2015. The aggregate impact of the corrections was a $0.8 million reduction to pre-tax income for the nine months ended September 30, 2015 and is not expected to be material to the current year annual results. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expense during the reporting period. Our more significant estimates include the obsolete and excess inventory reserves, warranty reserves, customer rebates, determination of the deferred revenue components of multiple element sales agreements, estimated costs to complete obligations associated with deferred revenues, estimated income tax provision and income tax contingencies, the fair value of stock-based Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers Revenue Recognition 2015-14, In April 2015, the FASB issued Accounting Standards Update No. 2015-05, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory . Inventory, ASU 2015-11

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	2. INCOME TAXES Our effective tax rate increased from 31.5% in the nine months ended September 30, 2014 to 36.9% in the nine months ended September 30, 2015. The increase in the effective tax rate between the two periods is primarily attributable to the release of a valuation allowance attributable to a foreign subsidiary in 2014, partially offset by settlements with tax authorities and expiration of statutes in 2015.

Pension Benefit Plan

Pension Benefit Plan	9 Months Ended
	Sep. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Pension Benefit Plan	3. PENSION BENEFIT PLAN We maintain a defined benefit pension plan covering employees in certain foreign countries. The following table summarizes the components of net periodic pension cost for the three and nine months ended September 30, 2015 and 2014: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2015 2014 2015 2014 Service cost $ 328 $ 299 $ 992 $ 910 Interest cost 153 209 464 640 Expected return on plan assets (252 ) (272 ) (763 ) (831 ) Amortization of actuarial losses 102 — 307 — Net periodic pension cost $ 331 $ 236 $ 1,000 $ 719

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	4. STOCK-BASED COMPENSATION The following table summarizes the stock-based compensation expense related to stock options, restricted stock units (RSUs) and restricted stock for the three and nine months ended September 30, 2015 and 2014, which was recognized as follows: Three Months Ended Nine Months Ended (In thousands) 2015 2014 2015 2014 Stock-based compensation expense included in cost of sales $ 59 $ 124 $ 202 $ 359 Selling, general and administrative expense 812 1,048 2,226 3,089 Research and development expense 803 975 2,360 2,848 Stock-based compensation expense included in operating expenses 1,615 2,023 4,586 5,937 Total stock-based compensation expense 1,674 2,147 4,788 6,296 Tax benefit for expense associated with non-qualified options (218 ) (298 ) (620 ) (878 ) Total stock-based compensation expense, net of tax $ 1,456 $ 1,849 $ 4,168 $ 5,418 The fair value of our stock options is estimated using the Black-Scholes model. The determination of the fair value of stock options on the date of grant using the Black-Scholes model is affected by our stock price as well as assumptions regarding a number of complex and subjective variables that may have a significant impact on the fair value estimate. There were no options granted during the three months ended September 30, 2014. The weighted-average assumptions and value of options granted during the three and nine months ended September 30, 2015 and the nine months ended September 30, 2014 are as follows: Three months ended Nine Months Ended September 30, 2015 September 30, 2015 September 30, 2014 Expected volatility 34.80 % 36.24 % 39.57 % Risk-free interest rate 1.84 % 1.70 % 1.86 % Expected dividend yield 2.13 % 1.94 % 1.38 % Expected life (in years) 6.24 6.32 6.25 Weighted-average estimated value $ 4.89 $ 5.89 $ 9.28 The fair value of our RSUs is calculated using a Monte Carlo Simulation valuation method. No RSUs were granted or vested during the three and nine months ended September 30, 2015 and 2014. Twelve thousand RSUs were forfeited during the nine months ended September 30, 2015. The fair value of restricted stock is equal to the closing price of our stock on the date of grant. No restricted stock was granted or forfeited during the three and nine months ended September 30, 2015 and 2014. Two thousand shares of restricted stock vested during the nine months ended September 30, 2015. Stock-based compensation expense recognized in our Consolidated Statements of Income for the three and nine months ended September 30, 2015 and 2014 is based on options, RSUs and restricted stock ultimately expected to vest, and has been reduced for estimated forfeitures. Estimated forfeitures for stock options are based upon historical experience and approximate 3.3% annually. We estimated a 0% forfeiture rate for our RSUs and restricted stock due to the limited number of recipients and historical experience for these awards. As of September 30, 2015, total compensation expense related to non-vested stock options, RSUs and restricted stock not yet recognized was approximately $10.6 million, which is expected to be recognized over an average remaining recognition period of 2.4 years. The following table is a summary of our stock options outstanding as of December 31, 2014 and September 30, 2015 and the changes that occurred during the nine months ended September 30, 2015: (In thousands, except per share amounts) Number of Weighted Avg. Weighted Avg. Aggregate Options outstanding, December 31, 2014 6,981 $ 23.62 6.45 $ 10,625 Options granted 5 $ 18.98 Options forfeited (294 ) $ 20.92 Options expired (406 ) $ 26.23 Options exercised (57 ) $ 16.02 Options outstanding, September 30, 2015 6,229 $ 23.64 5.69 $ — Options vested and expected to vest, September 30, 2015 6,154 $ 23.69 5.66 $ — Options exercisable, September 30, 2015 4,149 $ 25.43 4.33 $ — The aggregate intrinsic values in the table above represent the total pre-tax intrinsic value (the difference between the closing price of our stock on the last trading day of the quarter and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on September 30, 2015. The aggregate intrinsic value will change based on the fair market value of our stock. The total pre-tax intrinsic value of options exercised during the three and nine months ended September 30, 2015 was $4 thousand and $0.1 million, respectively.

Investments

Investments	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	5. INVESTMENTS At September 30, 2015, we held the following securities and investments, recorded at either fair value or cost. (In thousands) Amortized Gross Unrealized Carrying Gains Losses Deferred compensation plan assets $ 14,226 $ 1,536 $ (221 ) $ 15,541 Corporate bonds 87,555 38 (790 ) 86,803 Municipal fixed-rate bonds 51,971 129 (20 ) 52,080 Asset-backed bonds 5,490 — (3 ) 5,487 Mortgage/Agency-backed bonds 8,422 21 (15 ) 8,428 Government bonds 14,217 74 (2 ) 14,289 Marketable equity securities 29,508 5,462 (2,375 ) 32,595 Available-for-sale securities held at fair value $ 211,389 $ 7,260 $ (3,426 ) $ 215,223 Restricted investment held at cost 30,000 Other investments held at cost 1,371 Total carrying value of available-for-sale investments $ 246,594 At December 31, 2014, we held the following securities and investments, recorded at either fair value or cost. (In thousands) Amortized Gross Unrealized Carrying Gains Losses Deferred compensation plan assets $ 13,897 $ 2,409 $ (12 ) $ 16,294 Corporate bonds 111,261 186 (186 ) 111,261 Municipal fixed-rate bonds 127,341 480 (34 ) 127,787 Municipal variable rate demand notes 2,465 — — 2,465 Marketable equity securities 26,399 12,395 (539 ) 38,255 Available-for-sale securities held at fair value $ 281,363 $ 15,470 $ (771 ) $ 296,062 Restricted investment held at cost 30,000 Other investments held at cost 1,506 Total carrying value of available-for-sale investments $ 327,568 As of September 30, 2015, our corporate bonds, municipal fixed-rate bonds, asset-backed bonds, mortgage/agency-backed bonds, and government bonds had the following contractual maturities: (In thousands) Corporate bonds Municipal fixed-rate bonds Asset- backed bonds Mortgage / Agency- Government bonds Less than one year $ 23,732 $ 16,034 $ — $ 775 $ — One to two years 35,429 27,312 — — 4,198 Two to three years 27,642 7,310 1,065 1,000 1,878 Three to five years — 1,424 4,422 — 8,213 Five to ten years — — — 684 — More than ten years — — — 5,969 — Total $ 86,803 $ 52,080 $ 5,487 $ 8,428 $ 14,289 Actual maturities may differ from contractual maturities because some borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Our investment policy provides limitations for issuer concentration, which limits, at the time of purchase, the concentration in any one issuer to 5% of the market value of our total investment portfolio. At September 30, 2015, we held a $30.0 million restricted certificate of deposit, which is carried at cost. This investment serves as a collateral deposit against the principal amount outstanding under loans made to ADTRAN pursuant to an Alabama State Industrial Development Authority revenue bond (the Bond). At September 30, 2015, the estimated fair value of the Bond using a level 2 valuation technique was approximately $30.1 million, based on a debt security with a comparable interest rate and maturity and a Standard and Poor’s credit rating of AAA. For more information on the Bond, see “Debt” under “Liquidity and Capital Resources” in the “Management’s Discussion and Analysis of Financial Condition and Results of Operations” contained in Item 2 of Part I of this report. We review our investment portfolio for potential “other-than-temporary” declines in value on an individual investment basis. We assess, on a quarterly basis, significant declines in value which may be considered other-than-temporary and, if necessary, recognize and record the appropriate charge to write-down the carrying value of such investments. In making this assessment, we take into consideration qualitative and quantitative information, including but not limited to the following: the magnitude and duration of historical declines in market prices, credit rating activity, assessments of liquidity, public filings, and statements made by the issuer. We generally begin our identification of potential other-than-temporary impairments by reviewing any security with a fair value that has declined from its original or adjusted cost basis by 25% or more for six or more consecutive months. We then evaluate the individual security based on the previously identified factors to determine the amount of the write-down, if any. For the three and nine months ended September 30, 2015 and 2014, other-than-temporary impairment charges were not significant. Realized gains and losses on sales of securities are computed under the specific identification method. The following table presents gross realized gains and losses related to our investments. Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2015 2014 2015 2014 Gross realized gains $ 2,251 $ 2,728 $ 8,856 $ 7,363 Gross realized losses $ (191 ) $ (41 ) $ (426 ) $ (144 ) As of September 30, 2015 and 2014, gross unrealized losses related to individual securities in a continuous loss position for 12 months or longer were not significant. We have categorized our cash equivalents held in money market funds and our investments held at fair value into a three-level fair value hierarchy based on the priority of the inputs to the valuation technique for the cash equivalents and investments as follows: Level 1 - Values based on unadjusted quoted prices for identical assets or liabilities in an active market; Level 2 - Values based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly; Level 3 - Values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs include information supplied by investees. Fair Value Measurements at September 30, 2015 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 6,171 $ 6,171 $ — $ — Available-for-sale securities Deferred compensation plan assets 15,541 15,541 — — Available-for-sale debt securities Corporate bonds 86,803 — 86,803 — Municipal fixed-rate bonds 52,080 — 52,080 — Asset-backed bonds 5,487 — 5,487 — Mortgage/Agency-backed bonds 8,428 — 8,428 — Government bonds 14,289 13,289 1,000 — Available-for-sale marketable equity securities Marketable equity securities – technology industry 5,701 5,701 — — Marketable equity securities – other 26,894 26,894 — — Available-for-sale securities 215,223 61,425 153,798 — Total $ 221,394 $ 67,596 $ 153,798 $ — Fair Value Measurements at December 31, 2014 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 1,163 $ 1,163 $ — $ — Available-for-sale securities Deferred compensation plan assets 16,294 16,294 — — Available-for-sale debt securities Corporate bonds 111,261 — 111,261 — Municipal fixed-rate bonds 127,787 — 127,787 — Municipal variable rate demand notes 2,465 — 2,465 — Available-for-sale marketable equity securities Marketable equity securities – technology industry 9,661 9,661 — — Marketable equity securities – other 28,594 28,594 — — Available-for-sale securities 296,062 54,549 241,513 — Total $ 297,225 $ 55,712 $ 241,513 $ — The fair value of our Level 2 securities is calculated using a weighted average market price for each security. Market prices are obtained from a variety of industry standard data providers, security master files from large financial institutions, and other third-party sources. These multiple market prices are used as inputs into a distribution-curve-based algorithm to determine the daily market value of each security. Our municipal variable rate demand notes have a structure that implies a standard expected market price. The frequent interest rate resets make it reasonable to expect the price to stay at par. These securities are priced at the expected market price.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	6. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES We have certain customers and suppliers who are invoiced or pay in a non-functional currency. Changes in the monetary exchange rates may adversely affect our results of operations and financial condition. When appropriate, we enter into various derivative transactions to enhance our ability to manage the volatility relating to these typical business exposures. We do not hold or issue derivative instruments for trading or other speculative purposes. Our derivative instruments are recorded in the Consolidated Balance Sheets at their fair values. Our derivative instruments do not qualify for hedge accounting, and accordingly, all changes in the fair value of the instruments are recognized as other income (expense) in the Consolidated Statements of Income. The maximum contractual period for our derivatives is currently less than twelve months. Our derivative instruments are not subject to master netting arrangements and are not offset in the Consolidated Balance Sheets. As of September 30, 2015, we had forward contracts outstanding with notional amounts totaling €7.1 million ($8.0 million), which mature in the fourth quarter of 2015. The fair values of our derivative instruments recorded in the Consolidated Balance Sheet as of September 30, 2015 and December 31, 2014 were as follows: (In thousands) Balance Sheet Location September 30, 2015 December 31, 2014 Derivatives Not Designated as Hedging Instruments (Level 2): Foreign exchange contracts – asset derivatives Other receivables $ — $ 249 Foreign exchange contracts – liability derivatives Accounts payable $ (306 ) $ (10 ) The change in the fair values of our derivative instruments recorded in the Consolidated Statements of Income during the three and nine months ended September 30, 2015 and 2014 were as follows: Income Statement Location Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2015 2014 2015 2014 Derivatives Not Designated as Hedging Instruments: Foreign exchange contracts Other income (expense) $ 30 $ (191 ) $ 208 $ (739 )

Inventory

Inventory	9 Months Ended
	Sep. 30, 2015
Inventory Disclosure [Abstract]
Inventory	7. INVENTORY At September 30, 2015 and December 31, 2014, inventory consisted of the following: (In thousands) September 30, 2015 December 31, 2014 Raw materials $ 38,071 $ 34,831 Work in process 2,865 3,750 Finished goods 59,769 48,129 Total $ 100,705 $ 86,710 We establish reserves for estimated excess, obsolete, or unmarketable inventory equal to the difference between the cost of the inventory and the estimated fair value of the inventory based upon assumptions about future demand and market conditions. At September 30, 2015 and December 31, 2014, raw materials reserves totaled $16.3 million and $16.9 million, respectively, and finished goods inventory reserves totaled $8.3 million and $7.8 million, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	8. GOODWILL AND INTANGIBLE ASSETS Goodwill, all of which relates to our acquisition of Bluesocket, Inc. and is included in our Enterprise Networks division, was $3.5 million at September 30, 2015 and December 31, 2014. We evaluate the carrying value of goodwill during the fourth quarter of each year and between annual evaluations if events occur or circumstances change that would more likely than not reduce the fair value of the reporting unit below its carrying amount. We have elected to first assess the qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit to which the goodwill is assigned is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step impairment test. If we determine that it is more likely than not that its fair value is less than its carrying amount, then the two-step impairment test will be performed. There have been no impairment losses recorded since acquisition. Intangible assets are included in other assets in the accompanying Consolidated Balance Sheets and include intangibles acquired in conjunction with our acquisitions of Objectworld Communications Corporation on September 15, 2009, Bluesocket, Inc. on August 4, 2011, and the NSN BBA business on May 4, 2012. The following table presents our intangible assets as of September 30, 2015 and December 31, 2014: September 30, 2015 December 31, 2014 (In thousands) Gross Accumulated Net Value Gross Accumulated Net Value Customer relationships $ 5,953 $ (2,514 ) $ 3,439 $ 6,310 $ (2,136 ) $ 4,174 Developed technology 5,794 (4,185 ) 1,609 6,005 (3,577 ) 2,428 Intellectual property 2,340 (1,771 ) 569 2,340 (1,520 ) 820 Trade names 270 (250 ) 20 270 (205 ) 65 Other 11 (11 ) — 12 (11 ) 1 Total $ 14,368 $ (8,731 ) $ 5,637 $ 14,937 $ (7,449 ) $ 7,488 Amortization expense, all of which relates to business acquisitions, was $0.5 million and $0.6 million for the three months ended September 30, 2015 and 2014, respectively, and $1.5 million and $1.7 million for the nine months ended September 30, 2015 and 2014, respectively. As of September 30, 2015, the estimated future amortization expense of our intangible assets is as follows: (In thousands) Amount Remainder of 2015 $ 456 2016 1,682 2017 1,166 2018 704 2019 310 Thereafter 1,319 Total $ 5,637

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Stockholders' Equity	9. STOCKHOLDERS’ EQUITY A summary of the changes in stockholders’ equity for the nine months ended September 30, 2015 is as follows: (In thousands) Stockholders’ Equity Balance, December 31, 2014 $ 549,013 Net income 12,928 Dividend payments (13,989 ) Dividends accrued for unvested restricted stock units 5 Net unrealized losses on available-for-sale securities (net of tax) (6,577 ) Defined benefit plan adjustments 211 Foreign currency translation adjustment (3,797 ) Proceeds from stock option exercises 907 Purchase of treasury stock (65,808 ) Income tax benefit from exercise of stock options (40 ) Stock-based compensation expense 4,788 Balance, September 30, 2015 $ 477,641 Stock Repurchase Program Since 1997, our Board of Directors has approved multiple share repurchase programs that have authorized open market repurchase transactions of up to 50.0 million shares of our common stock. During the nine months ended September 30, 2015, we repurchased 3.9 million shares of our common stock at an average price of $16.69 per share. As of September 30, 2015, we have the authority to purchase an additional 5.8 million shares of our common stock under the current plans approved by the Board of Directors. Stock Option Exercises We issued 0.1 million shares of treasury stock during the nine months ended September 30, 2015 to accommodate employee stock option exercises. The stock options had exercise prices ranging from $15.29 to $22.53. We received proceeds totaling $0.9 million from the exercise of these stock options during the nine months ended September 30, 2015. Dividend Payments During the nine months ended September 30, 2015, we paid cash dividends as follows (in thousands except per share amounts): Record Date Payment Date Per Share Amount Total Dividend Paid February 5, 2015 February 19, 2015 $ 0.09 $ 4,811 May 7, 2015 May 21, 2015 $ 0.09 $ 4,698 July 30, 2015 August 13, 2015 $ 0.09 $ 4,480 Other Comprehensive Income Other comprehensive income consists of unrealized gains (losses) on available-for-sale securities, reclassification adjustments for amounts included in net income related to impairments of available-for-sale securities, realized gains (losses) on available-for-sale securities, and amortization of actuarial gains (losses) related to our defined benefit plan, defined benefit plan adjustments, and foreign currency translation adjustments. The following tables present changes in accumulated other comprehensive income, net of tax, by component for the three months ended September 30, 2015 and 2014: Three Months Ended September 30, 2015 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Other comprehensive income (loss) before reclassifications (3,034 ) — (1,351 ) (4,385 ) Amounts reclassified from accumulated other comprehensive income (1,257 ) 71 — (1,186 ) Net current period other comprehensive income (loss) (4,291 ) 71 (1,351 ) (5,571 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 ) Three Months Ended September 30, 2014 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Foreign Total Beginning balance $ 11,035 $ (891 ) $ 1,293 $ 11,437 Other comprehensive income (loss) before reclassifications (1,602 ) — (2,568 ) (4,170 ) Amounts reclassified from accumulated other comprehensive income (1,546 ) — — (1,546 ) Net current period other comprehensive income (loss) (3,148 ) — (2,568 ) (5,716 ) Ending balance $ 7,887 $ (891 ) $ (1,275 ) $ 5,721 The following tables present changes in accumulated other comprehensive income, net of tax, by component for the nine months ended September 30, 2015 and 2014: Nine Months Ended September 30, 2015 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 8,964 $ (5,757 ) $ (3,282 ) $ (75 ) Other comprehensive income (loss) before reclassifications (1,497 ) — (3,797 ) (5,294 ) Amounts reclassified from accumulated other comprehensive income (5,080 ) 211 — (4,869 ) Net current period other comprehensive income (loss) (6,577 ) 211 (3,797 ) (10,163 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 ) Nine Months Ended September 30, 2014 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 10,737 $ (891 ) $ 907 $ 10,753 Other comprehensive income (loss) before reclassifications 1,316 — (2,182 ) (866 ) Amounts reclassified from accumulated other comprehensive income (4,166 ) — — (4,166 ) Net current period other comprehensive income (loss) (2,850 ) — (2,182 ) (5,032 ) Ending balance $ 7,887 $ (891 ) $ (1,275 ) $ 5,721 The following tables present the details of reclassifications out of accumulated other comprehensive income for the three months ended September 30, 2015 and 2014: (In thousands) Three Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 2,098 Net realized investment gain Impairment expense (37 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (103 ) (1) Total reclassifications for the period, before tax 1,958 Tax (expense) benefit (772 ) Total reclassifications for the period, net of tax $ 1,186 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Three Months Ended September 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 2,565 Net realized investment gain Impairment expense (30 ) Net realized investment gain Total reclassifications for the period, before tax 2,535 Tax (expense) benefit (989 ) Total reclassifications for the period, net of tax $ 1,546 The following tables present the details of reclassifications out of accumulated other comprehensive income for the nine months ended September 30, 2015 and 2014: (In thousands) Nine Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 8,438 Net realized investment gain Impairment expense (110 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (306 ) (1) Total reclassifications for the period, before tax 8,022 Tax (expense) benefit (3,153 ) Total reclassifications for the period, net of tax $ 4,869 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Nine Months Ended September 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 6,895 Net realized investment gain Impairment expense (64 ) Net realized investment gain Total reclassifications for the period, before tax 6,831 Tax (expense) benefit (2,665 ) Total reclassifications for the period, net of tax $ 4,166 The following table presents the tax effects related to the change in each component of other comprehensive income for the three months ended September 30, 2015 and 2014: Three Months Ended September 30, 2015 Three Months Ended September 30, 2014 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Unrealized gains (losses) on available-for-sale securities $ (4,974 ) $ 1,940 $ (3,034 ) $ (2,626 ) $ 1,024 $ (1,602 ) Reclassification adjustment for amounts included in net income (1,958 ) 772 (1,186 ) (2,535 ) 989 (1,546 ) Foreign currency translation adjustment (1,351 ) — (1,351 ) (2,568 ) — (2,568 ) Total Other Comprehensive Income (Loss) $ (8,283 ) $ 2,712 $ (5,571 ) $ (7,729 ) $ 2,013 $ (5,716 ) The following table presents the tax effects related to the change in each component of other comprehensive income for the nine months ended September 30, 2015 and 2014: Nine Months Ended September 30, 2015 Nine Months Ended September 30, 2014 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Unrealized gains (losses) on available-for-sale securities $ (2,454 ) $ 957 $ (1,497 ) $ 2,157 $ (841 ) $ 1,316 Reclassification adjustment for amounts included in net income (8,022 ) 3,153 (4,869 ) (6,831 ) 2,665 (4,166 ) Foreign currency translation adjustment (3,797 ) — (3,797 ) (2,182 ) — (2,182 ) Total Other Comprehensive Income (Loss) $ (14,273 ) $ 4,110 $ (10,163 ) $ (6,856 ) $ 1,824 $ (5,032 )

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings per Share	10. EARNINGS PER SHARE A summary of the calculation of basic and diluted earnings per share for the three and nine months ended September 30, 2015 and 2014 is as follows: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share amounts) 2015 2014 2015 2014 Numerator Net income $ 7,067 $ 11,326 $ 12,928 $ 35,328 Denominator Weighted average number of shares – basic 49,862 54,521 51,682 55,552 Effect of dilutive securities Stock options 29 266 94 402 Restricted stock and restricted stock units 36 37 16 22 Weighted average number of shares – diluted 49,927 54,824 51,792 55,976 Net income per share – basic $ 0.14 $ 0.21 $ 0.25 $ 0.64 Net income per share – diluted $ 0.14 $ 0.21 $ 0.25 $ 0.63 Anti-dilutive options to purchase common stock outstanding were excluded from the above calculations. Anti-dilutive options totaled 6.0 million and 4.5 million for the three months ended September 30, 2015 and 2014, respectively, and 6.1 million and 3.1 million for the nine months ended September 30, 2015 and 2014, respectively.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment Information	11. SEGMENT INFORMATION We operate in two reportable segments: (1) the Carrier Networks Division and (2) the Enterprise Networks Division. We evaluate the performance of our segments based on gross profit; therefore, selling, general and administrative expenses, research and development expenses, interest and dividend income, interest expense, net realized investment gain/loss, other income/expense and provision for taxes are reported on an entity-wide basis only. There are no inter-segment revenues. The following tables present information about the reported sales and gross profit of our reportable segments for the three and nine months ended September 30, 2015 and 2014. Asset information by reportable segment is not reported, since we do not produce such information internally. Three Months Ended September 30, 2015 September 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 131,273 $ 55,796 $ 132,972 $ 61,687 Enterprise Networks 26,805 14,853 29,920 16,570 Total $ 158,078 $ 70,649 $ 162,892 $ 78,257 Nine Months Ended September 30, 2015 September 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 382,684 $ 160,354 $ 394,589 $ 191,093 Enterprise Networks 78,367 44,104 91,436 51,751 Total $ 461,051 $ 204,458 $ 486,025 $ 242,844 Sales by Product Our three major product categories are Carrier Systems, Business Networking and Loop Access. Carrier Systems • Broadband Access • Total Access ® • hiX 5600 Series of MSANs • Total Access 1100/1200 Series of Fiber to the Node (FTTN) products • hiX 1100 Series of Fiber to the Node (FTTN) products • VDSL2 Vectoring based Digital Subscriber Line Access Multiplexer (DSLAM) products • ADTRAN 500 Series of FTTdp G.fast Distribution Point Units (DPU) • Optical • Optical Networking Edge (ONE) • NetVanta 8000 Series of Fiber Ethernet Access Devices (EAD) • NetVanta 8400 Series of 10Gig Multi-service Edge Switches • OPTI-6100 and Total Access 3000 optical Multi-Service Provisioning Platforms (MSPP) • Pluggable Optical Products, including SFP, XFP, and SFP+ • Time Division Multiplexed (TDM) systems Business Networking • Internetworking products • Total Access IP Business Gateways • Optical Network Terminals (ONTs) • Bluesocket ® ® • NetVanta ® • Access Routers • Enterprise Session Border Controllers (eSBC) • Managed Ethernet Switches • IP Business Gateways • Unified Communications (UC) solutions • Carrier Ethernet Network Terminating Equipment (NTE) • Carrier Ethernet Routers and Gateways • Network Management Solutions Loop Access • High bit-rate Digital Subscriber Line (HDSL) products • Digital Data Service (DDS) • Integrated Services Digital Network (ISDN) products • T1/E1/T3 Channel Service Units/Data Service Units (CSUs/DSUs) • TRACER fixed-wireless products The table below presents sales information by product category for the three and nine months ended September 30, 2015 and 2014: Three Months Ended Nine Months Ended (In thousands) 2015 2014 2015 2014 Carrier Systems $ 111,044 $ 113,950 $ 330,522 $ 342,327 Business Networking 39,127 39,746 108,718 119,634 Loop Access 7,907 9,196 21,811 24,064 Total $ 158,078 $ 162,892 $ 461,051 $ 486,025 In addition, we identify subcategories of product revenues, which we divide into core products and legacy products. Our core products consist of Broadband Access and Optical products (included in Carrier Systems), and Internetworking products (included in Business Networking). Our legacy products include HDSL products (included in Loop Access) and other products not included in the aforementioned core products. The table below presents subcategory revenues for the three and nine months ended September 30, 2015 and 2014: Three Months Ended Nine Months Ended (In thousands) 2015 2014 2015 2014 Core Products Broadband Access (included in Carrier Systems) $ 94,116 $ 96,084 $ 279,656 $ 285,920 Optical (included in Carrier Systems) 13,733 13,686 42,669 42,308 Internetworking (included in Business Networking) 38,123 38,630 105,440 116,562 Subtotal 145,972 148,400 427,765 444,790 Legacy Products HDSL (does not include T1) (included in Loop Access) 7,397 8,400 20,499 22,075 Other products (excluding HDSL) 4,709 6,092 12,787 19,160 Subtotal 12,106 14,492 33,286 41,235 Total $ 158,078 $ 162,892 $ 461,051 $ 486,025

Liability for Warranty Returns

Liability for Warranty Returns	9 Months Ended
	Sep. 30, 2015
Product Warranties Disclosures [Abstract]
Liability for Warranty Returns	12. LIABILITY FOR WARRANTY RETURNS Our products generally include warranties of 90 days to ten years for product defects. We accrue for warranty returns at the time revenue is recognized based on our estimate of the cost to repair or replace the defective products. We engage in extensive product quality programs and processes, including actively monitoring and evaluating the quality of our component suppliers. Our products continue to become more complex in both size and functionality as many of our product offerings migrate from line card applications to total systems. The increasing complexity of our products will cause warranty incidences, when they arise, to be more costly. Our estimates regarding future warranty obligations may change due to product failure rates, material usage, and other rework costs incurred in correcting a product failure. In addition, from time to time, specific warranty accruals may be recorded if unforeseen problems arise. Should our actual experience relative to these factors be worse than our estimates, we will be required to record additional warranty expense. Alternatively, if we provide for more reserves than we require, we will reverse a portion of such provisions in future periods. The liability for warranty obligations totaled $8.7 million and $8.4 million at September 30, 2015 and December 31, 2014, respectively. These liabilities are included in accrued expenses in the accompanying Consolidated Balance Sheets. A summary of warranty expense and write-off activity for the nine months ended September 30, 2015 and 2014 is as follows: Nine Months Ended (In thousands) 2015 2014 Balance at beginning of period $ 8,415 $ 8,977 Plus: Amounts charged to cost and expenses 1,905 2,770 Less: Deductions (1,604 ) (3,099 ) Balance at end of period $ 8,716 $ 8,648

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2015
Related Party Transactions [Abstract]
Related Party Transactions	13. RELATED PARTY TRANSACTIONS During 2014, we employed the law firm of our director emeritus for legal services. All bills for services rendered by this firm were reviewed and approved by our Chief Financial Officer. We believe that the fees for such services were comparable to those charged by other firms for services rendered to us. The services of our director emeritus ended with his death on September 7, 2014. For the three and nine months ended September 30, 2014, we incurred fees of $10 thousand and $70 thousand, respectively, for these legal services.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. COMMITMENTS AND CONTINGENCIES In the ordinary course of business, we may be subject to various legal proceedings and claims, including employment disputes, patent claims, disputes over contract agreements and other commercial disputes. In some cases, claimants seek damages or other relief, such as royalty payments related to patents, which, if granted, could require significant expenditures. Although the outcome of any claim or litigation can never be certain, it is our opinion that the outcome of all contingencies of which we are currently aware will not materially affect our business, operations, financial condition or cash flows. We have committed to invest up to an aggregate of $7.9 million in two private equity funds, and we have contributed $8.4 million as of September 30, 2015, of which $7.7 million has been applied to these commitments.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	15. SUBSEQUENT EVENTS On October 13, 2015, we announced that our Board of Directors declared a quarterly cash dividend of $0.09 per common share to be paid to stockholders of record at the close of business on October 29, 2015. The payment date will be November 12, 2015. The quarterly dividend payment will be approximately $4.5 million. In July 2003, our Board of Directors elected to begin declaring quarterly dividends on our common stock considering the tax treatment of dividends and adequate levels of Company liquidity.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements of ADTRAN ® In the opinion of management, all adjustments necessary to fairly state these interim statements have been recorded and are of a normal and recurring nature. The results of operations for an interim period are not necessarily indicative of the results for the full year. The interim statements should be read in conjunction with the financial statements and notes thereto included in ADTRAN’s Annual Report on Form 10-K for the year ended December 31, 2014, filed on February 24, 2015 with the SEC.
Changes in Classifications	Changes in Classifications We reclassified $2.3 million from other receivables to accounts receivable at December 31, 2014 to conform to the current period presentation.
Out of Period Adjustment	Out of Period Adjustment In connection with the preparation of our Condensed Consolidated Financial Statements, we recorded corrections of certain out of period, immaterial misstatements that occurred in prior periods, the most significant of which resulted in an increase in Other Expense of $1.3 million in the first quarter of 2015. The aggregate impact of the corrections was a $0.8 million reduction to pre-tax income for the nine months ended September 30, 2015 and is not expected to be material to the current year annual results.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expense during the reporting period. Our more significant estimates include the obsolete and excess inventory reserves, warranty reserves, customer rebates, determination of the deferred revenue components of multiple element sales agreements, estimated costs to complete obligations associated with deferred revenues, estimated income tax provision and income tax contingencies, the fair value of stock-based compensation, impairment of goodwill, valuation and estimated lives of intangible assets, estimated pension liability, fair value of investments, and the evaluation of other-than-temporary declines in the value of investments. Actual amounts could differ significantly from these estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers Revenue Recognition In April 2015, the FASB issued Accounting Standards Update No. 2015-05, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement

Pension Benefit Plan (Tables)

Pension Benefit Plan (Tables)	9 Months Ended
	Sep. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Summarization of Components of Net Periodic Pension Cost	The following table summarizes the components of net periodic pension cost for the three and nine months ended September 30, 2015 and 2014: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2015 2014 2015 2014 Service cost $ 328 $ 299 $ 992 $ 910 Interest cost 153 209 464 640 Expected return on plan assets (252 ) (272 ) (763 ) (831 ) Amortization of actuarial losses 102 — 307 — Net periodic pension cost $ 331 $ 236 $ 1,000 $ 719

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense Related to Stock Options, Restricted Stock Units (RSUs) and Restricted Stock	The following table summarizes the stock-based compensation expense related to stock options, restricted stock units (RSUs) and restricted stock for the three and nine months ended September 30, 2015 and 2014, which was recognized as follows: Three Months Ended Nine Months Ended (In thousands) 2015 2014 2015 2014 Stock-based compensation expense included in cost of sales $ 59 $ 124 $ 202 $ 359 Selling, general and administrative expense 812 1,048 2,226 3,089 Research and development expense 803 975 2,360 2,848 Stock-based compensation expense included in operating expenses 1,615 2,023 4,586 5,937 Total stock-based compensation expense 1,674 2,147 4,788 6,296 Tax benefit for expense associated with non-qualified options (218 ) (298 ) (620 ) (878 ) Total stock-based compensation expense, net of tax $ 1,456 $ 1,849 $ 4,168 $ 5,418
Summary of Weighted-Average Assumptions and Value of Options Granted	The weighted-average assumptions and value of options granted during the three and nine months ended September 30, 2015 and the nine months ended September 30, 2014 are as follows: Three months ended Nine Months Ended September 30, 2015 September 30, 2015 September 30, 2014 Expected volatility 34.80 % 36.24 % 39.57 % Risk-free interest rate 1.84 % 1.70 % 1.86 % Expected dividend yield 2.13 % 1.94 % 1.38 % Expected life (in years) 6.24 6.32 6.25 Weighted-average estimated value $ 4.89 $ 5.89 $ 9.28
Summary of Stock Options Outstanding	The following table is a summary of our stock options outstanding as of December 31, 2014 and September 30, 2015 and the changes that occurred during the nine months ended September 30, 2015: (In thousands, except per share amounts) Number of Weighted Avg. Weighted Avg. Aggregate Options outstanding, December 31, 2014 6,981 $ 23.62 6.45 $ 10,625 Options granted 5 $ 18.98 Options forfeited (294 ) $ 20.92 Options expired (406 ) $ 26.23 Options exercised (57 ) $ 16.02 Options outstanding, September 30, 2015 6,229 $ 23.64 5.69 $ — Options vested and expected to vest, September 30, 2015 6,154 $ 23.69 5.66 $ — Options exercisable, September 30, 2015 4,149 $ 25.43 4.33 $ —

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Securities and Investments, Recorded at Either Fair Value or Cost	At September 30, 2015, we held the following securities and investments, recorded at either fair value or cost. (In thousands) Amortized Gross Unrealized Carrying Gains Losses Deferred compensation plan assets $ 14,226 $ 1,536 $ (221 ) $ 15,541 Corporate bonds 87,555 38 (790 ) 86,803 Municipal fixed-rate bonds 51,971 129 (20 ) 52,080 Asset-backed bonds 5,490 — (3 ) 5,487 Mortgage/Agency-backed bonds 8,422 21 (15 ) 8,428 Government bonds 14,217 74 (2 ) 14,289 Marketable equity securities 29,508 5,462 (2,375 ) 32,595 Available-for-sale securities held at fair value $ 211,389 $ 7,260 $ (3,426 ) $ 215,223 Restricted investment held at cost 30,000 Other investments held at cost 1,371 Total carrying value of available-for-sale investments $ 246,594 At December 31, 2014, we held the following securities and investments, recorded at either fair value or cost. (In thousands) Amortized Gross Unrealized Carrying Gains Losses Deferred compensation plan assets $ 13,897 $ 2,409 $ (12 ) $ 16,294 Corporate bonds 111,261 186 (186 ) 111,261 Municipal fixed-rate bonds 127,341 480 (34 ) 127,787 Municipal variable rate demand notes 2,465 — — 2,465 Marketable equity securities 26,399 12,395 (539 ) 38,255 Available-for-sale securities held at fair value $ 281,363 $ 15,470 $ (771 ) $ 296,062 Restricted investment held at cost 30,000 Other investments held at cost 1,506 Total carrying value of available-for-sale investments $ 327,568
Contractual Maturities of Corporate Bonds, Municipal Fixed-Rate Bonds, Asset-Backed Bonds, Mortgage/Agency-Backed Bonds, and Government Bonds	As of September 30, 2015, our corporate bonds, municipal fixed-rate bonds, asset-backed bonds, mortgage/agency-backed bonds, and government bonds had the following contractual maturities: (In thousands) Corporate bonds Municipal fixed-rate bonds Asset- backed bonds Mortgage / Agency- Government bonds Less than one year $ 23,732 $ 16,034 $ — $ 775 $ — One to two years 35,429 27,312 — — 4,198 Two to three years 27,642 7,310 1,065 1,000 1,878 Three to five years — 1,424 4,422 — 8,213 Five to ten years — — — 684 — More than ten years — — — 5,969 — Total $ 86,803 $ 52,080 $ 5,487 $ 8,428 $ 14,289
Gross Realized Gains and Losses on Sale of Securities	The following table presents gross realized gains and losses related to our investments. Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2015 2014 2015 2014 Gross realized gains $ 2,251 $ 2,728 $ 8,856 $ 7,363 Gross realized losses $ (191 ) $ (41 ) $ (426 ) $ (144 )
Fair Value Measurements of Cash Equivalents Held in Money Market Funds and Investments	We have categorized our cash equivalents held in money market funds and our investments held at fair value into a three-level fair value hierarchy based on the priority of the inputs to the valuation technique for the cash equivalents and investments as follows: Level 1 - Values based on unadjusted quoted prices for identical assets or liabilities in an active market; Level 2 - Values based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly; Level 3 - Values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs include information supplied by investees. Fair Value Measurements at September 30, 2015 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 6,171 $ 6,171 $ — $ — Available-for-sale securities Deferred compensation plan assets 15,541 15,541 — — Available-for-sale debt securities Corporate bonds 86,803 — 86,803 — Municipal fixed-rate bonds 52,080 — 52,080 — Asset-backed bonds 5,487 — 5,487 — Mortgage/Agency-backed bonds 8,428 — 8,428 — Government bonds 14,289 13,289 1,000 — Available-for-sale marketable equity securities Marketable equity securities – technology industry 5,701 5,701 — — Marketable equity securities – other 26,894 26,894 — — Available-for-sale securities 215,223 61,425 153,798 — Total $ 221,394 $ 67,596 $ 153,798 $ — Fair Value Measurements at December 31, 2014 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 1,163 $ 1,163 $ — $ — Available-for-sale securities Deferred compensation plan assets 16,294 16,294 — — Available-for-sale debt securities Corporate bonds 111,261 — 111,261 — Municipal fixed-rate bonds 127,787 — 127,787 — Municipal variable rate demand notes 2,465 — 2,465 — Available-for-sale marketable equity securities Marketable equity securities – technology industry 9,661 9,661 — — Marketable equity securities – other 28,594 28,594 — — Available-for-sale securities 296,062 54,549 241,513 — Total $ 297,225 $ 55,712 $ 241,513 $ —

Derivative Instruments and He26

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fair Values of Hedging Instruments Recorded in Consolidated Balance Sheet	The fair values of our derivative instruments recorded in the Consolidated Balance Sheet as of September 30, 2015 and December 31, 2014 were as follows: (In thousands) Balance Sheet Location September 30, 2015 December 31, 2014 Derivatives Not Designated as Hedging Instruments (Level 2): Foreign exchange contracts – asset derivatives Other receivables $ — $ 249 Foreign exchange contracts – liability derivatives Accounts payable $ (306 ) $ (10 )
Schedule of Change in Fair Values of Derivative Instruments Recorded in Consolidated Statements of Income	The change in the fair values of our derivative instruments recorded in the Consolidated Statements of Income during the three and nine months ended September 30, 2015 and 2014 were as follows: Income Statement Location Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2015 2014 2015 2014 Derivatives Not Designated as Hedging Instruments: Foreign exchange contracts Other income (expense) $ 30 $ (191 ) $ 208 $ (739 )

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2015
Inventory Disclosure [Abstract]
Components of Inventory	At September 30, 2015 and December 31, 2014, inventory consisted of the following: (In thousands) September 30, 2015 December 31, 2014 Raw materials $ 38,071 $ 34,831 Work in process 2,865 3,750 Finished goods 59,769 48,129 Total $ 100,705 $ 86,710

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	The following table presents our intangible assets as of September 30, 2015 and December 31, 2014: September 30, 2015 December 31, 2014 (In thousands) Gross Accumulated Net Value Gross Accumulated Net Value Customer relationships $ 5,953 $ (2,514 ) $ 3,439 $ 6,310 $ (2,136 ) $ 4,174 Developed technology 5,794 (4,185 ) 1,609 6,005 (3,577 ) 2,428 Intellectual property 2,340 (1,771 ) 569 2,340 (1,520 ) 820 Trade names 270 (250 ) 20 270 (205 ) 65 Other 11 (11 ) — 12 (11 ) 1 Total $ 14,368 $ (8,731 ) $ 5,637 $ 14,937 $ (7,449 ) $ 7,488
Estimated Future Amortization Expense Related to Intangible Assets	As of September 30, 2015, the estimated future amortization expense of our intangible assets is as follows: (In thousands) Amount Remainder of 2015 $ 456 2016 1,682 2017 1,166 2018 704 2019 310 Thereafter 1,319 Total $ 5,637

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Summary of Changes in Stockholders' Equity	A summary of the changes in stockholders’ equity for the nine months ended September 30, 2015 is as follows: (In thousands) Stockholders’ Equity Balance, December 31, 2014 $ 549,013 Net income 12,928 Dividend payments (13,989 ) Dividends accrued for unvested restricted stock units 5 Net unrealized losses on available-for-sale securities (net of tax) (6,577 ) Defined benefit plan adjustments 211 Foreign currency translation adjustment (3,797 ) Proceeds from stock option exercises 907 Purchase of treasury stock (65,808 ) Income tax benefit from exercise of stock options (40 ) Stock-based compensation expense 4,788 Balance, September 30, 2015 $ 477,641
Cash Dividends	During the nine months ended September 30, 2015, we paid cash dividends as follows (in thousands except per share amounts): Record Date Payment Date Per Share Amount Total Dividend Paid February 5, 2015 February 19, 2015 $ 0.09 $ 4,811 May 7, 2015 May 21, 2015 $ 0.09 $ 4,698 July 30, 2015 August 13, 2015 $ 0.09 $ 4,480
Changes in Accumulated Other Comprehensive Income, Net of Tax by Component	The following tables present changes in accumulated other comprehensive income, net of tax, by component for the three months ended September 30, 2015 and 2014: Three Months Ended September 30, 2015 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Other comprehensive income (loss) before reclassifications (3,034 ) — (1,351 ) (4,385 ) Amounts reclassified from accumulated other comprehensive income (1,257 ) 71 — (1,186 ) Net current period other comprehensive income (loss) (4,291 ) 71 (1,351 ) (5,571 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 ) Three Months Ended September 30, 2014 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Foreign Total Beginning balance $ 11,035 $ (891 ) $ 1,293 $ 11,437 Other comprehensive income (loss) before reclassifications (1,602 ) — (2,568 ) (4,170 ) Amounts reclassified from accumulated other comprehensive income (1,546 ) — — (1,546 ) Net current period other comprehensive income (loss) (3,148 ) — (2,568 ) (5,716 ) Ending balance $ 7,887 $ (891 ) $ (1,275 ) $ 5,721 The following tables present changes in accumulated other comprehensive income, net of tax, by component for the nine months ended September 30, 2015 and 2014: Nine Months Ended September 30, 2015 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 8,964 $ (5,757 ) $ (3,282 ) $ (75 ) Other comprehensive income (loss) before reclassifications (1,497 ) — (3,797 ) (5,294 ) Amounts reclassified from accumulated other comprehensive income (5,080 ) 211 — (4,869 ) Net current period other comprehensive income (loss) (6,577 ) 211 (3,797 ) (10,163 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 ) Nine Months Ended September 30, 2014 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 10,737 $ (891 ) $ 907 $ 10,753 Other comprehensive income (loss) before reclassifications 1,316 — (2,182 ) (866 ) Amounts reclassified from accumulated other comprehensive income (4,166 ) — — (4,166 ) Net current period other comprehensive income (loss) (2,850 ) — (2,182 ) (5,032 ) Ending balance $ 7,887 $ (891 ) $ (1,275 ) $ 5,721
Reclassifications Out of Accumulated Other Comprehensive Income	The following tables present the details of reclassifications out of accumulated other comprehensive income for the three months ended September 30, 2015 and 2014: (In thousands) Three Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 2,098 Net realized investment gain Impairment expense (37 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (103 ) (1) Total reclassifications for the period, before tax 1,958 Tax (expense) benefit (772 ) Total reclassifications for the period, net of tax $ 1,186 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Three Months Ended September 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 2,565 Net realized investment gain Impairment expense (30 ) Net realized investment gain Total reclassifications for the period, before tax 2,535 Tax (expense) benefit (989 ) Total reclassifications for the period, net of tax $ 1,546 The following tables present the details of reclassifications out of accumulated other comprehensive income for the nine months ended September 30, 2015 and 2014: (In thousands) Nine Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 8,438 Net realized investment gain Impairment expense (110 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (306 ) (1) Total reclassifications for the period, before tax 8,022 Tax (expense) benefit (3,153 ) Total reclassifications for the period, net of tax $ 4,869 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Nine Months Ended September 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 6,895 Net realized investment gain Impairment expense (64 ) Net realized investment gain Total reclassifications for the period, before tax 6,831 Tax (expense) benefit (2,665 ) Total reclassifications for the period, net of tax $ 4,166
Other Comprehensive Income	The following table presents the tax effects related to the change in each component of other comprehensive income for the three months ended September 30, 2015 and 2014: Three Months Ended September 30, 2015 Three Months Ended September 30, 2014 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Unrealized gains (losses) on available-for-sale securities $ (4,974 ) $ 1,940 $ (3,034 ) $ (2,626 ) $ 1,024 $ (1,602 ) Reclassification adjustment for amounts included in net income (1,958 ) 772 (1,186 ) (2,535 ) 989 (1,546 ) Foreign currency translation adjustment (1,351 ) — (1,351 ) (2,568 ) — (2,568 ) Total Other Comprehensive Income (Loss) $ (8,283 ) $ 2,712 $ (5,571 ) $ (7,729 ) $ 2,013 $ (5,716 ) The following table presents the tax effects related to the change in each component of other comprehensive income for the nine months ended September 30, 2015 and 2014: Nine Months Ended September 30, 2015 Nine Months Ended September 30, 2014 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Unrealized gains (losses) on available-for-sale securities $ (2,454 ) $ 957 $ (1,497 ) $ 2,157 $ (841 ) $ 1,316 Reclassification adjustment for amounts included in net income (8,022 ) 3,153 (4,869 ) (6,831 ) 2,665 (4,166 ) Foreign currency translation adjustment (3,797 ) — (3,797 ) (2,182 ) — (2,182 ) Total Other Comprehensive Income (Loss) $ (14,273 ) $ 4,110 $ (10,163 ) $ (6,856 ) $ 1,824 $ (5,032 )

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Summary of Calculation of Basic and Diluted Earnings Per Share	A summary of the calculation of basic and diluted earnings per share for the three and nine months ended September 30, 2015 and 2014 is as follows: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share amounts) 2015 2014 2015 2014 Numerator Net income $ 7,067 $ 11,326 $ 12,928 $ 35,328 Denominator Weighted average number of shares – basic 49,862 54,521 51,682 55,552 Effect of dilutive securities Stock options 29 266 94 402 Restricted stock and restricted stock units 36 37 16 22 Weighted average number of shares – diluted 49,927 54,824 51,792 55,976 Net income per share – basic $ 0.14 $ 0.21 $ 0.25 $ 0.64 Net income per share – diluted $ 0.14 $ 0.21 $ 0.25 $ 0.63

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Sales and Gross Profit of Reportable Segments	The following tables present information about the reported sales and gross profit of our reportable segments for the three and nine months ended September 30, 2015 and 2014. Asset information by reportable segment is not reported, since we do not produce such information internally. Three Months Ended September 30, 2015 September 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 131,273 $ 55,796 $ 132,972 $ 61,687 Enterprise Networks 26,805 14,853 29,920 16,570 Total $ 158,078 $ 70,649 $ 162,892 $ 78,257 Nine Months Ended September 30, 2015 September 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 382,684 $ 160,354 $ 394,589 $ 191,093 Enterprise Networks 78,367 44,104 91,436 51,751 Total $ 461,051 $ 204,458 $ 486,025 $ 242,844
Sales Information by Product Category	The table below presents sales information by product category for the three and nine months ended September 30, 2015 and 2014: Three Months Ended Nine Months Ended (In thousands) 2015 2014 2015 2014 Carrier Systems $ 111,044 $ 113,950 $ 330,522 $ 342,327 Business Networking 39,127 39,746 108,718 119,634 Loop Access 7,907 9,196 21,811 24,064 Total $ 158,078 $ 162,892 $ 461,051 $ 486,025
Subcategory Revenues	The table below presents subcategory revenues for the three and nine months ended September 30, 2015 and 2014: Three Months Ended Nine Months Ended (In thousands) 2015 2014 2015 2014 Core Products Broadband Access (included in Carrier Systems) $ 94,116 $ 96,084 $ 279,656 $ 285,920 Optical (included in Carrier Systems) 13,733 13,686 42,669 42,308 Internetworking (included in Business Networking) 38,123 38,630 105,440 116,562 Subtotal 145,972 148,400 427,765 444,790 Legacy Products HDSL (does not include T1) (included in Loop Access) 7,397 8,400 20,499 22,075 Other products (excluding HDSL) 4,709 6,092 12,787 19,160 Subtotal 12,106 14,492 33,286 41,235 Total $ 158,078 $ 162,892 $ 461,051 $ 486,025

Liability for Warranty Returns

Liability for Warranty Returns (Tables)	9 Months Ended
	Sep. 30, 2015
Product Warranties Disclosures [Abstract]
Summary of Warranty Expense and Write-Off Activity	A summary of warranty expense and write-off activity for the nine months ended September 30, 2015 and 2014 is as follows: Nine Months Ended (In thousands) 2015 2014 Balance at beginning of period $ 8,415 $ 8,977 Plus: Amounts charged to cost and expenses 1,905 2,770 Less: Deductions (1,604 ) (3,099 ) Balance at end of period $ 8,716 $ 8,648

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Summary of Significant Accounting Policy [Line Items]
Reduction of pre-tax income		$ 0.8
Increase in other expenses	$ 1.3
Other Receivables [Member]
Summary of Significant Accounting Policy [Line Items]
Prior period reclassification adjustment			$ (2.3)
Accounts Receivable [Member]
Summary of Significant Accounting Policy [Line Items]
Prior period reclassification adjustment			$ 2.3

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Effective tax rate	36.90%	31.50%

Pension Benefit Plan - Summariz

Pension Benefit Plan - Summarization of Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 328	$ 299	$ 992	$ 910
Interest cost	153	209	464	640
Expected return on plan assets	(252)	(272)	(763)	(831)
Amortization of actuarial losses	102		307
Net periodic pension cost	$ 331	$ 236	$ 1,000	$ 719

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense Related to Stock Options, Restricted Stock Units (RSUs) and Restricted Stock (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,674	$ 2,147	$ 4,788	$ 6,296
Tax benefit for expense associated with non-qualified options	(218)	(298)	(620)	(878)
Total stock-based compensation expense, net of tax	1,456	1,849	4,168	5,418
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	59	124	202	359
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	812	1,048	2,226	3,089
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	803	975	2,360	2,848
Operating Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,615	$ 2,023	$ 4,586	$ 5,937

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, granted		0	5,000
Estimated forfeitures for stock options			3.30%
Compensation expense related to non-vested stock options, RSUs and restricted stock not yet recognized	$ 10,600		$ 10,600
Recognition period of non-vested compensation cost			2 years 4 months 24 days
Total pre-tax intrinsic value of options exercised	$ 4		$ 100
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs and restricted stock grants in period	0	0	0	0
Number of RSUs and restricted stock forfeitures in period			12,000
Number of RSUs and restricted stock vesting in period	0	0	0	0
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs and restricted stock grants in period	0	0	0	0
Number of RSUs and restricted stock forfeitures in period	0	0	0	0
Number of RSUs and restricted stock vesting in period	2,000
RSUs and Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forfeiture rate for RSUs and restricted stock			0.00%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Weighted-Average Assumptions and Value of Options Granted (Detail) - Stock Options [Member] - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	34.80%	36.24%	39.57%
Risk-free interest rate	1.84%	1.70%	1.86%
Expected dividend yield	2.13%	1.94%	1.38%
Expected life (in years)	6 years 2 months 27 days	6 years 3 months 26 days	6 years 3 months
Weighted-average estimated value	$ 4.89	$ 5.89	$ 9.28

Stock-Based Compensation - Su39

Stock-Based Compensation - Summary of Stock Options Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Aggregate Intrinsic Value, Options outstanding, Beginning Balance			$ 10,625
Number of Options, outstanding, Beginning Balance		6,981,000
Number of options, granted	0	5,000
Number of Options, forfeited		(294,000)
Number of Options, expired		(406,000)
Number of Options, exercised		(57,000)
Number of Options, outstanding, Ending Balance		6,229,000	6,981,000
Number of Options, vested and expected to vest, Ending Balance		6,154,000
Number of Options, Options exercisable		4,149,000
Weighted Average Exercise Price, outstanding, Beginning Balance		$ 23.62
Weighted Average Exercise Price, granted		18.98
Weighted Average Exercise Price, forfeited		20.92
Weighted Average Exercise Price, expired		26.23
Weighted Average Exercise Price, exercised		16.02
Weighted Average Exercise Price, outstanding, Ending Balance		23.64	$ 23.62
Weighted Average Exercise Price, vested and expected to vest, Ending Balance		23.69
Weighted Average Exercise Price, Options exercisable		$ 25.43
Weighted Average Remaining Contractual Life In Years, Options outstanding		5 years 8 months 9 days	6 years 5 months 12 days
Weighted Average Remaining Contractual Life In Years, Options vested and expected to vest		5 years 7 months 28 days
Weighted Average Remaining Contractual Life In Years, Options exercisable		4 years 3 months 29 days
Aggregate Intrinsic Value, Options vested and expected to vest		$ 0
Aggregate Intrinsic Value, Options exercisable		$ 0

Investments - Securities and In

Investments - Securities and Investments, Recorded at Either Fair Value or Cost (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 211,389	$ 281,363
Gross Unrealized Gains	7,260	15,470
Gross Unrealized Losses	(3,426)	(771)
Available-for-sale-securities, Carrying Value	215,223	296,062
Restricted investment held at cost	30,000	30,000
Other investments held at cost	1,371	1,506
Total carrying value of available-for-sale investments	246,594	327,568
Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,226	13,897
Gross Unrealized Gains	1,536	2,409
Gross Unrealized Losses	(221)	(12)
Available-for-sale-securities, Carrying Value	15,541	16,294
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	87,555	111,261
Gross Unrealized Gains	38	186
Gross Unrealized Losses	(790)	(186)
Available-for-sale-securities, Carrying Value	86,803	111,261
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	51,971	127,341
Gross Unrealized Gains	129	480
Gross Unrealized Losses	(20)	(34)
Available-for-sale-securities, Carrying Value	52,080	127,787
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,490
Gross Unrealized Losses	(3)
Available-for-sale-securities, Carrying Value	5,487
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,422
Gross Unrealized Gains	21
Gross Unrealized Losses	(15)
Available-for-sale-securities, Carrying Value	8,428
Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,217
Gross Unrealized Gains	74
Gross Unrealized Losses	(2)
Available-for-sale-securities, Carrying Value	14,289
Municipal Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,465
Available-for-sale-securities, Carrying Value		2,465
Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	29,508	26,399
Gross Unrealized Gains	5,462	12,395
Gross Unrealized Losses	(2,375)	(539)
Available-for-sale-securities, Carrying Value	$ 32,595	$ 38,255

Investments - Contractual Matur

Investments - Contractual Maturities of Corporate Bonds, Municipal Fixed-Rate Bonds, Asset-Backed Bonds, Mortgage/Agency-Backed Bonds, and Government Bonds (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale-securities, Fair Value/Carrying Value	$ 215,223	$ 296,062
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	23,732
One to two years	35,429
Two to three years	27,642
Available-for-sale-securities, Fair Value/Carrying Value	86,803	111,261
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	16,034
One to two years	27,312
Two to three years	7,310
Three to five years	1,424
Available-for-sale-securities, Fair Value/Carrying Value	52,080	$ 127,787
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Two to three years	1,065
Three to five years	4,422
Available-for-sale-securities, Fair Value/Carrying Value	5,487
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	775
Two to three years	1,000
Five to ten years	684
More than ten years	5,969
Available-for-sale-securities, Fair Value/Carrying Value	8,428
Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
One to two years	4,198
Two to three years	1,878
Three to five years	8,213
Available-for-sale-securities, Fair Value/Carrying Value	$ 14,289

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Restricted certificate of deposit held	$ 30,000	$ 30,000
Identification of potential other-than-temporary impairments	25.00%
Alabama State Industrial Development Authority [Member] | Taxable Revenue Bond [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Investments [Line Items]
Estimated fair value of bond	$ 30,100
Investment [Member] | Issuer Concentration [Member] | Market Value of Total Investment Portfolio [Member]
Schedule of Investments [Line Items]
Investment concentration risk percentage	5.00%

Investments - Gross Realized Ga

Investments - Gross Realized Gains and Losses on Sale of Securities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 2,251	$ 2,728	$ 8,856	$ 7,363
Gross realized losses	$ (191)	$ (41)	$ (426)	$ (144)

Investments - Fair Value Measur

Investments - Fair Value Measurements of Cash Equivalents Held in Money Market Funds and Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 215,223	$ 296,062
Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	15,541	16,294
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	86,803	111,261
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	52,080	127,787
Municipal Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		2,465
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	5,487
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	8,428
Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	14,289
Fair Value, Measurements, Recurring [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	215,223	296,062
Total	221,394	297,225
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	61,425	54,549
Total	67,596	55,712
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	153,798	241,513
Total	153,798	241,513
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	6,171	1,163
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	6,171	1,163
Fair Value, Measurements, Recurring [Member] | Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	15,541	16,294
Fair Value, Measurements, Recurring [Member] | Deferred Compensation Plan Assets [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	15,541	16,294
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	86,803	111,261
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	86,803	111,261
Fair Value, Measurements, Recurring [Member] | Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	52,080	127,787
Fair Value, Measurements, Recurring [Member] | Municipal Fixed-Rate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	52,080	127,787
Fair Value, Measurements, Recurring [Member] | Municipal Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		2,465
Fair Value, Measurements, Recurring [Member] | Municipal Variable Rate Demand Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities		2,465
Fair Value, Measurements, Recurring [Member] | Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	5,487
Fair Value, Measurements, Recurring [Member] | Asset-Backed Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	5,487
Fair Value, Measurements, Recurring [Member] | Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	8,428
Fair Value, Measurements, Recurring [Member] | Mortgage/Agency-Backed Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	8,428
Fair Value, Measurements, Recurring [Member] | Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	14,289
Fair Value, Measurements, Recurring [Member] | Government Bonds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	13,289
Fair Value, Measurements, Recurring [Member] | Government Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	1,000
Fair Value, Measurements, Recurring [Member] | Marketable Equity Securities - Technology Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	5,701	9,661
Fair Value, Measurements, Recurring [Member] | Marketable Equity Securities - Technology Industry [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	5,701	9,661
Fair Value, Measurements, Recurring [Member] | Marketable Equity Securities - Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	26,894	28,594
Fair Value, Measurements, Recurring [Member] | Marketable Equity Securities - Other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 26,894	$ 28,594

Derivative Instruments and He45

Derivative Instruments and Hedging Activities - Additional Information (Detail) - 9 months ended Sep. 30, 2015	USD ($)	EUR (€)
Derivative [Line Items]
Maximum contractual period for derivatives	12 months
Forward Contracts [Member]
Derivative [Line Items]
Derivative, notional amount	$ 8,000,000	€ 7,100,000
Derivative maturity year	2,015

Derivative Instruments and He46

Derivative Instruments and Hedging Activities - Schedule of Fair Values of Hedging Instruments Recorded in Consolidated Balance Sheet (Detail) - Significant Other Observable Inputs (Level 2) [Member] - Foreign Exchange Contracts [Member] - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Other Receivables [Member]
Derivatives Not Designated as Hedging Instruments (Level 2):
Derivatives asset, fair value		$ 249
Accounts Payable [Member]
Derivatives Not Designated as Hedging Instruments (Level 2):
Derivatives liability, fair value	$ (306)	$ (10)

Derivative Instruments and He47

Derivative Instruments and Hedging Activities - Schedule of Change in Fair Values of Derivative Instruments Recorded in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Foreign Exchange Contracts [Member] | Other Income (Expense) [Member]
Derivatives Not Designated as Hedging Instruments:
Derivative instrument, gain or loss	$ 30	$ (191)	$ 208	$ (739)

Inventory - Components of Inven

Inventory - Components of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 38,071	$ 34,831
Work in process	2,865	3,750
Finished goods	59,769	48,129
Total	$ 100,705	$ 86,710

Inventory - Additional Informat

Inventory - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Raw Materials [Member]
Inventory [Line Items]
Inventory valuation reserves	$ 16.3	$ 16.9
Finished Goods [Member]
Inventory [Line Items]
Inventory valuation reserves	$ 8.3	$ 7.8

Goodwill and Intangible Asset50

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, relates to acquisition			$ 3,500,000		$ 3,500,000
Impairment losses			0
Amortization expense	$ 500,000	$ 600,000	$ 1,500,000	$ 1,700,000

Goodwill and Intangible Asset51

Goodwill and Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Goodwill [Line Items]
Gross Value	$ 14,368	$ 14,937
Accumulated Amortization	(8,731)	(7,449)
Net Value	5,637	7,488
Customer Relationships [Member]
Goodwill [Line Items]
Gross Value	5,953	6,310
Accumulated Amortization	(2,514)	(2,136)
Net Value	3,439	4,174
Developed Technology [Member]
Goodwill [Line Items]
Gross Value	5,794	6,005
Accumulated Amortization	(4,185)	(3,577)
Net Value	1,609	2,428
Intellectual Property [Member]
Goodwill [Line Items]
Gross Value	2,340	2,340
Accumulated Amortization	(1,771)	(1,520)
Net Value	569	820
Trade Names [Member]
Goodwill [Line Items]
Gross Value	270	270
Accumulated Amortization	(250)	(205)
Net Value	20	65
Other [Member]
Goodwill [Line Items]
Gross Value	11	12
Accumulated Amortization	$ (11)	(11)
Net Value		$ 1

Goodwill and Intangible Asset52

Goodwill and Intangible Assets - Estimated Future Amortization Expense Related to Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2015	$ 456
2,016	1,682
2,017	1,166
2,018	704
2,019	310
Thereafter	1,319
Net Value	$ 5,637	$ 7,488

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Changes in Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Equity [Abstract]
Beginning Balance			$ 549,013
Net Income	$ 7,067	$ 11,326	12,928	$ 35,328
Dividend payments			(13,989)
Dividends accrued for unvested restricted stock units			5
Net unrealized losses on available-for-sale securities (net of tax)	(4,291)	(3,148)	(6,577)	(2,850)
Defined benefit plan adjustments	71		211
Foreign currency translation adjustment	(1,351)	$ (2,568)	(3,797)	(2,182)
Proceeds from stock option exercises			907	$ 2,311
Purchase of treasury stock			(65,808)
Income tax benefit from exercise of stock options			(40)
Stock-based compensation expense			4,788
Ending Balance	$ 477,641		$ 477,641

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchased, shares	3,900,000
Shares repurchased, average price per share	$ 16.69
Additional shares authorized for purchase	5,800,000
Number of Options, exercised	(57,000)
Exercise price of stock options, lower range limit	$ 15.29
Exercise price of stock options, upper range limit	$ 22.53
Proceeds from stock option exercises	$ 907	$ 2,311
Predecessor [Member]
Equity, Class of Treasury Stock [Line Items]
Maximum shares authorized for repurchase, prior and new announcements and total after new announcement	50,000,000

Stockholders' Equity - Cash Div

Stockholders' Equity - Cash Dividends (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Dividends Payable [Line Items]
Record Date			Oct. 29, 2015
Payment Date			Nov. 12, 2015
Per Share Amount	$ 0.09	$ 0.09	$ 0.27	$ 0.27
Total Dividend Paid			$ 13,989	$ 15,060
Cash Dividends Paid in February [Member]
Dividends Payable [Line Items]
Record Date			Feb. 5, 2015
Payment Date			Feb. 19, 2015
Per Share Amount			$ 0.09
Total Dividend Paid			$ 4,811
Cash Dividends Paid in May [Member]
Dividends Payable [Line Items]
Record Date			May 7, 2015
Payment Date			May 21, 2015
Per Share Amount			$ 0.09
Total Dividend Paid			$ 4,698
Cash Dividends Paid in August [Member]
Dividends Payable [Line Items]
Record Date			Jul. 30, 2015
Payment Date			Aug. 13, 2015
Per Share Amount			$ 0.09
Total Dividend Paid			$ 4,480

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Accumulated Other Comprehensive Income, Net of Tax by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (4,667)	$ 11,437	$ (75)	$ 10,753
Other comprehensive income (loss) before reclassifications	(4,385)	(4,170)	(5,294)	(866)
Amounts reclassified from accumulated other comprehensive income	(1,186)	(1,546)	(4,869)	(4,166)
Other Comprehensive income (loss), net of tax	(5,571)	(5,716)	(10,163)	(5,032)
Ending balance	(10,238)	5,721	(10,238)	5,721
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	6,678	11,035	8,964	10,737
Other comprehensive income (loss) before reclassifications	(3,034)	(1,602)	(1,497)	1,316
Amounts reclassified from accumulated other comprehensive income	(1,257)	(1,546)	(5,080)	(4,166)
Other Comprehensive income (loss), net of tax	(4,291)	(3,148)	(6,577)	(2,850)
Ending balance	2,387	7,887	2,387	7,887
Defined Benefit Plan Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(5,617)	(891)	(5,757)	(891)
Amounts reclassified from accumulated other comprehensive income	71		211
Other Comprehensive income (loss), net of tax	71		211
Ending balance	(5,546)	(891)	(5,546)	(891)
Foreign Currency Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(5,728)	1,293	(3,282)	907
Other comprehensive income (loss) before reclassifications	(1,351)	(2,568)	(3,797)	(2,182)
Other Comprehensive income (loss), net of tax	(1,351)	(2,568)	(3,797)	(2,182)
Ending balance	$ (7,079)	$ (1,275)	$ (7,079)	$ (1,275)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Income before provision for income taxes	$ 10,872	$ 15,061	$ 20,493	$ 51,551
Tax (expense) benefit	(3,805)	(3,735)	(7,565)	(16,223)
Total reclassifications for the period, net of tax	7,067	11,326	12,928	35,328
Reclassification Out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit plan adjustments - actuarial losses	(103)		(306)
Income before provision for income taxes	1,958	2,535	8,022	6,831
Tax (expense) benefit	(772)	(989)	(3,153)	(2,665)
Total reclassifications for the period, net of tax	1,186	1,546	4,869	4,166
Unrealized Gains (Losses) on Available-for-Sale Securities [Member] | Reclassification Out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net realized investment gain	2,098	2,565	8,438	6,895
Impairment Expense [Member] | Reclassification Out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net realized investment gain	$ (37)	$ (30)	$ (110)	$ (64)

Stockholders' Equity - Other Co

Stockholders' Equity - Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Equity [Abstract]
Unrealized gains (losses) on available-for-sale securities, Before-Tax Amount	$ (4,974)	$ (2,626)	$ (2,454)	$ 2,157
Reclassification adjustment for amounts included in net income, Before-Tax Amount	(1,958)	(2,535)	(8,022)	(6,831)
Foreign currency translation adjustment, Before-Tax Amount	(1,351)	(2,568)	(3,797)	(2,182)
Total Other Comprehensive Income (Loss), Before-Tax Amount	(8,283)	(7,729)	(14,273)	(6,856)
Unrealized gains (losses) on available-for-sale securities, Tax (Expense) Benefit	1,940	1,024	957	(841)
Reclassification adjustment for amounts included in net income, Tax Benefit	772	989	3,153	2,665
Foreign currency translation adjustment, Tax Benefit	0	0	0	0
Total Other Comprehensive Income (Loss), Tax (Expense) Benefit	2,712	2,013	4,110	1,824
Unrealized gains (losses) on available-for-sale securities, Net-of-Tax Amount	(3,034)	(1,602)	(1,497)	1,316
Reclassification adjustment for amounts included in net income, Net-of-Tax Amount	(1,186)	(1,546)	(4,869)	(4,166)
Foreign currency translation adjustment, Net-of-Tax Amount	(1,351)	(2,568)	(3,797)	(2,182)
Other Comprehensive income (loss), net of tax	$ (5,571)	$ (5,716)	$ (10,163)	$ (5,032)

Earnings Per Share - Summary of

Earnings Per Share - Summary of Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator
Net Income	$ 7,067	$ 11,326	$ 12,928	$ 35,328
Denominator
Weighted average number of shares - basic	49,862	54,521	51,682	55,552
Effect of dilutive securities
Stock options	29	266	94	402
Restricted stock and restricted stock units	36	37	16	22
Weighted average number of shares - diluted	49,927	54,824	51,792	55,976
Net income per share - basic	$ 0.14	$ 0.21	$ 0.25	$ 0.64
Net income per share - diluted	$ 0.14	$ 0.21	$ 0.25	$ 0.63

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Anti-dilutive options, Total	6	4.5	6.1	3.1

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2015SegmentProduct_Category
Segment Reporting [Abstract]
Number of operating reportable segments	2
Number of product categories | Product_Category	3

Segment Information - Sales and

Segment Information - Sales and Gross Profit of Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Sales	$ 158,078	$ 162,892	$ 461,051	$ 486,025
Gross Profit	70,649	78,257	204,458	242,844
Carrier Networks [Member]
Segment Reporting Information [Line Items]
Sales	131,273	132,972	382,684	394,589
Gross Profit	55,796	61,687	160,354	191,093
Enterprise Networks [Member]
Segment Reporting Information [Line Items]
Sales	26,805	29,920	78,367	91,436
Gross Profit	$ 14,853	$ 16,570	$ 44,104	$ 51,751

Segment Information - Sales Inf

Segment Information - Sales Information by Product Category (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue from External Customer [Line Items]
Sales	$ 158,078	$ 162,892	$ 461,051	$ 486,025
Carrier Systems [Member]
Revenue from External Customer [Line Items]
Sales	111,044	113,950	330,522	342,327
Business Networking [Member]
Revenue from External Customer [Line Items]
Sales	39,127	39,746	108,718	119,634
Loop Access [Member]
Revenue from External Customer [Line Items]
Sales	$ 7,907	$ 9,196	$ 21,811	$ 24,064

Segment Information - Subcatego

Segment Information - Subcategory Revenues (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue from External Customer [Line Items]
Sales	$ 158,078	$ 162,892	$ 461,051	$ 486,025
Core Products [Member]
Revenue from External Customer [Line Items]
Sales	145,972	148,400	427,765	444,790
Legacy Products [Member]
Revenue from External Customer [Line Items]
Sales	12,106	14,492	33,286	41,235
Broadband Access (Included in Carrier Systems) [Member] | Core Products [Member]
Revenue from External Customer [Line Items]
Sales	94,116	96,084	279,656	285,920
Optical (Included in Carrier Systems) [Member] | Core Products [Member]
Revenue from External Customer [Line Items]
Sales	13,733	13,686	42,669	42,308
Internetworking (Included in Business Networking) [Member] | Core Products [Member]
Revenue from External Customer [Line Items]
Sales	38,123	38,630	105,440	116,562
HDSL (Does not Include T1) (Included in Loop Access) [Member] | Legacy Products [Member]
Revenue from External Customer [Line Items]
Sales	7,397	8,400	20,499	22,075
Other Products (Excluding HDSL) [Member] | Legacy Products [Member]
Revenue from External Customer [Line Items]
Sales	$ 4,709	$ 6,092	$ 12,787	$ 19,160

Liability for Warranty Return65

Liability for Warranty Returns - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Product Warranties Disclosures [Abstract]
Period of warranty for product defects	90 days to ten years
Liability for warranty obligations	$ 8,716	$ 8,415	$ 8,648	$ 8,977

Liability for Warranty Return66

Liability for Warranty Returns - Summary of Warranty Expense and Write-Off Activity (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Product Warranties Disclosures [Abstract]
Balance at beginning of period	$ 8,415	$ 8,977
Plus:Amounts charged to cost and expenses	1,905	2,770
Less:Deductions	(1,604)	(3,099)
Balance at end of period	$ 8,716	$ 8,648

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Director Emeritus [Member]
Related Party Transaction
Related party legal fees	$ 10	$ 70

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Sep. 30, 2015USD ($)EquityUnit
Contingencies And Commitments [Line Items]
Number of private equity funds | EquityUnit	2
Commitments towards private equity funds	$ 7.7
Investment Commitments [Member]
Contingencies And Commitments [Line Items]
Aggregate investment committed in private equity funds	7.9
Private Equity Funds [Member]
Contingencies And Commitments [Line Items]
Contribution to private equity funds	$ 8.4

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Oct. 13, 2015	Sep. 30, 2015	Nov. 12, 2015
Subsequent Event [Line Items]
Dividend declaration date		Oct. 13, 2015
Dividend record date		Oct. 29, 2015
Dividend payment date		Nov. 12, 2015
Subsequent Events [Member]
Subsequent Event [Line Items]
Cash dividend per common share	$ 0.09
Cash dividend			$ 4.5