ADTRAN (ADTN) 10-Q 5 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 22, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
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		49,928,495

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 87,215	$ 73,439
Short-term investments	54,127	46,919
Accounts receivable, less allowance for doubtful accounts of $21 and $136 at June 30, 2015 and December 31, 2014, respectively	89,088	88,502
Other receivables	31,442	33,295
Inventory, net	100,048	86,710
Prepaid expenses	5,817	5,129
Deferred tax assets, net	17,038	17,095
Total Current Assets	384,775	351,089
Property, plant and equipment, net	73,347	74,828
Deferred tax assets, net	20,473	17,694
Goodwill	3,492	3,492
Other assets	10,236	10,942
Long-term investments	216,665	280,649
Total Assets	708,988	738,694
Current Liabilities
Accounts payable	85,456	56,414
Unearned revenue	17,495	22,762
Accrued expenses	15,538	11,077
Accrued wages and benefits	15,515	13,855
Income tax payable, net	10,072	14,901
Total Current Liabilities	144,076	119,009
Non-current unearned revenue	9,444	10,948
Other non-current liabilities	31,268	30,924
Bonds payable	28,800	28,800
Total Liabilities	$ 213,588	$ 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 50,573 shares outstanding at June 30, 2015 and 79,652 shares issued and 53,431 shares outstanding at December 31, 2014	$ 797	$ 797
Additional paid-in capital	244,920	241,829
Accumulated other comprehensive loss	(4,667)	(75)
Retained earnings	903,448	907,751
Less treasury stock at cost: 29,079 and 26,221 shares at June 30, 2015 and December 31, 2014, respectively	(649,098)	(601,289)
Total Stockholders' Equity	495,400	549,013
Total Liabilities and Stockholders' Equity	$ 708,988	$ 738,694

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 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	50,573,000	53,431,000
Treasury stock, shares	29,079,000	26,221,000

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Sales	$ 160,138	$ 176,129	$ 302,973	$ 323,133
Cost of sales	91,892	89,332	169,164	158,546
Gross Profit	68,246	86,797	133,809	164,587
Selling, general and administrative expenses	32,123	33,788	63,187	67,727
Research and development expenses	35,479	33,670	68,015	66,223
Operating Income	644	19,339	2,607	30,637
Interest and dividend income	908	1,054	1,841	2,348
Interest expense	(149)	(148)	(297)	(375)
Net realized investment gain	3,255	2,340	6,370	4,532
Other expense, net	(547)	(774)	(900)	(652)
Income before provision for income taxes	4,111	21,811	9,621	36,490
Provision for income taxes	(1,567)	(7,416)	(3,760)	(12,488)
Net Income	$ 2,544	$ 14,395	$ 5,861	$ 24,002
Weighted average shares outstanding - basic	51,822	55,409	52,607	56,077
Weighted average shares outstanding - diluted	51,917	55,729	52,742	56,559
Earnings per common share - basic	$ 0.05	$ 0.26	$ 0.11	$ 0.43
Earnings per common share - diluted	0.05	0.26	0.11	0.42
Dividend per share	$ 0.09	$ 0.09	$ 0.18	$ 0.18

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 2,544	$ 14,395	$ 5,861	$ 24,002
Other Comprehensive Income (Loss), net of tax:
Net unrealized gains (losses) on available-for-sale securities	(1,783)	1,219	(2,286)	298
Defined benefit plan adjustments	72		140
Foreign currency translation	872	134	(2,446)	386
Other Comprehensive Income (Loss), net of tax	(839)	1,353	(4,592)	684
Comprehensive Income, net of tax	$ 1,705	$ 15,748	$ 1,269	$ 24,686

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net Income	$ 5,861	$ 24,002
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,256	7,467
Amortization of net premium on available-for-sale investments	1,578	2,272
Net realized gain on long-term investments	(6,370)	(4,532)
Net loss on disposal of property, plant and equipment	160	37
Stock-based compensation expense	3,114	4,149
Deferred income taxes	(1,743)	377
Tax benefit from stock option exercises	(23)	67
Excess tax benefits from stock-based compensation arrangements	38	(58)
Changes in operating assets and liabilities:
Accounts receivable, net	(2,003)	(31,583)
Other receivables	(119)	(4,072)
Inventory	(14,254)	841
Prepaid expenses and other assets	(1,433)	(3,103)
Accounts payable	30,938	14,425
Accrued expenses and other liabilities	2,175	8,248
Income tax payable, net	(3,961)	4,442
Net cash provided by operating activities	21,214	22,979
Cash flows from investing activities:
Purchases of property, plant and equipment	(5,392)	(4,919)
Proceeds from disposals of property, plant and equipment	8	1
Proceeds from sales and maturities of available-for-sale investments	120,422	166,518
Purchases of available-for-sale investments	(62,626)	(106,406)
Net cash provided by investing activities	52,412	55,194
Cash flows from financing activities:
Proceeds from stock option exercises	833	1,781
Purchases of treasury stock	(49,307)	(53,091)
Dividend payments	(9,509)	(10,137)
Payments on long-term debt		(16,500)
Excess tax benefits from stock-based compensation arrangements	(38)	58
Net cash used in financing activities	(58,021)	(77,889)
Net increase in cash and cash equivalents	15,605	284
Effect of exchange rate changes	(1,829)	321
Cash and cash equivalents, beginning of period	73,439	58,298
Cash and cash equivalents, end of period	87,215	58,903
Supplemental disclosure of non-cash investing activities:
Purchases of property, plant and equipment included in accounts payable	$ 270	$ 423

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 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 six months ended June 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 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 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 In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory . Inventory,

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	2. INCOME TAXES Our effective tax rate increased from 34.2% in the six months ended June 30, 2014 to 39.1% in the six months ended June 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.

Pension Benefit Plan

Pension Benefit Plan	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2015 2014 2015 2014 Service cost $ 324 $ 306 $ 664 $ 611 Interest cost 152 216 311 431 Expected return on plan assets (250 ) (280 ) (511 ) (559 ) Amortization of actuarial losses 100 — 205 — Net periodic pension cost $ 326 $ 242 $ 669 $ 483

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014, which was recognized as follows: Three Months Ended Six Months Ended (In thousands) 2015 2014 2015 2014 Stock-based compensation expense included in cost of sales $ 53 $ 119 $ 143 $ 235 Selling, general and administrative expense 723 1,015 1,414 2,041 Research and development expense 699 958 1,557 1,873 Stock-based compensation expense included in operating expenses 1,422 1,973 2,971 3,914 Total stock-based compensation expense 1,475 2,092 3,114 4,149 Tax benefit for expense associated with non-qualified options (222 ) (296 ) (402 ) (580 ) Total stock-based compensation expense, net of tax $ 1,253 $ 1,796 $ 2,712 $ 3,569 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 June 30, 2015 and 2014. The weighted-average assumptions and value of options granted for the six months ended June 30, 2015 and 2014 are as follows: Six Months Ended June 30, June 30, Expected volatility 38.75 % 39.57 % Risk-free interest rate 1.46 % 1.86 % Expected dividend yield 1.60 % 1.38 % Expected life (in years) 6.47 6.25 Weighted-average estimated value $ 7.63 $ 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 six months ended June 30, 2015 and 2014. Twelve thousand RSUs were forfeited during the six months ended June 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 six months ended June 30, 2015 and 2014. Two thousand shares of restricted stock vested during the three months ended June 30, 2015. Stock-based compensation expense recognized in our Consolidated Statements of Income for the three and six months ended June 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 June 30, 2015, total compensation expense related to non-vested stock options, RSUs and restricted stock not yet recognized was approximately $12.6 million, which is expected to be recognized over an average remaining recognition period of 2.5 years. The following table is a summary of our stock options outstanding as of December 31, 2014 and June 30, 2015 and the changes that occurred during the six months ended June 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 2 $ 22.56 Options forfeited (243 ) $ 21.01 Options expired (157 ) $ 26.78 Options exercised (52 ) $ 16.08 Options outstanding, June 30, 2015 6,531 $ 23.70 5.92 $ 446 Options vested and expected to vest, June 30, 2015 6,440 $ 23.75 5.85 $ 331 Options exercisable, June 30, 2015 4,190 $ 25.21 4.51 $ 446 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 June 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 six months ended June 30, 2015 was $25 thousand and $0.1 million, respectively.

Investments

Investments	6 Months Ended
	Jun. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	5. INVESTMENTS At June 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 $ 14,046 $ 2,601 $ (113 ) $ 16,534 Corporate bonds 114,446 123 (139 ) 114,430 Municipal fixed-rate bonds 67,302 130 (45 ) 67,387 Municipal variable rate demand notes 3,695 — — 3,695 Marketable equity securities 28,901 9,265 (866 ) 37,300 Available-for-sale securities held at fair value $ 228,390 $ 12,119 $ (1,163 ) $ 239,346 Restricted investment held at cost 30,000 Other investments held at cost 1,446 Total carrying value of available-for-sale investments $ 270,792 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 June 30, 2015, our corporate bonds and municipal fixed-rate bonds had the following contractual maturities: (In thousands) Corporate Municipal Less than one year $ 32,179 $ 18,254 One to two years 42,510 35,462 Two to three years 39,741 12,460 Three to five years — 1,211 Total $ 114,430 $ 67,387 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 June 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 June 30, 2015, the estimated fair value of the Bond using a level 2 valuation technique was approximately $29.9 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 six months ended June 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 June 30, Six Months Ended June 30, (In thousands) 2015 2014 2015 2014 Gross realized gains $ 3,459 $ 2,407 $ 6,604 $ 4,635 Gross realized losses $ (204 ) $ (67 ) $ (234 ) $ (103 ) As of June 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 June 30, 2015 Using (In thousands) Fair Value Quoted Prices (Level 1) Significant (Level 2) Significant (Level 3) Cash equivalents Money market funds $ 1,087 $ 1,087 $ — $ — Available-for-sale securities Deferred compensation plan assets 16,534 16,534 — — Available-for-sale debt securities Corporate bonds 114,430 — 114,430 — Municipal fixed-rate bonds 67,387 — 67,387 — Municipal variable rate demand notes 3,695 — 3,695 — Available-for-sale marketable equity securities Marketable equity securities – technology industry 7,786 7,786 — — Marketable equity securities – other 29,514 29,514 — — Available-for-sale securities 239,346 53,834 185,512 — Total $ 240,433 $ 54,921 $ 185,512 $ — Fair Value Measurements at December 31, 2014 Using (In thousands) Fair Value Quoted Prices (Level 1) Significant (Level 2) Significant (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	6 Months Ended
	Jun. 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 June 30, 2015, we had forward contracts outstanding with notional amounts totaling €39.0 million ($43.4 million), which mature at various times throughout 2015. The fair values of our derivative instruments recorded in the Consolidated Balance Sheet as of June 30, 2015 and December 31, 2014 were as follows: (In thousands) Balance Sheet June 30, 2015 December 31, Derivatives Not Designated as Hedging Instruments (Level 2): Foreign exchange contracts – asset derivatives Other receivables $ 447 $ 249 Foreign exchange contracts – liability derivatives Accounts payable $ (832 ) $ (10 ) The change in the fair values of our derivative instruments recorded in the Consolidated Statements of Income during the three and six months ended June 30, 2015 and 2014 were as follows: Three Months Ended Six Months Ended Income Statement June 30, June 30, (In thousands) 2015 2014 2015 2014 Derivatives Not Designated as Hedging Instruments: Foreign exchange contracts Other income (expense) $ (1,299 ) $ (438 ) $ 177 $ (5

Inventory

Inventory	6 Months Ended
	Jun. 30, 2015
Inventory Disclosure [Abstract]
Inventory	7. INVENTORY At June 30, 2015 and December 31, 2014, inventory consisted of the following: (In thousands) June 30, December 31, Raw materials $ 38,819 $ 34,831 Work in process 3,489 3,750 Finished goods 57,740 48,129 Total $ 100,048 $ 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 June 30, 2015 and December 31, 2014, raw materials reserves totaled $17.6 million and $16.9 million, respectively, and finished goods inventory reserves totaled $7.6 million and $7.8 million, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 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 June 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 June 30, 2015 and December 31, 2014: (In thousands) June 30, 2015 December 31, 2014 Gross Accumulated Net Gross Accumulated Net Customer relationships $ 5,937 $ (2,350 ) $ 3,587 $ 6,310 $ (2,136 ) $ 4,174 Developed technology 5,784 (3,962 ) 1,822 6,005 (3,577 ) 2,428 Intellectual property 2,340 (1,687 ) 653 2,340 (1,520 ) 820 Trade names 270 (235 ) 35 270 (205 ) 65 Other 11 (11 ) — 12 (11 ) 1 Total $ 14,342 $ (8,245 ) $ 6,097 $ 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 June 30, 2015 and 2014, respectively, and $1.0 million and $1.2 million for the six months ended June 30, 2015 and 2014, respectively. As of June 30, 2015, the estimated future amortization expense of our intangible assets is as follows: (In thousands) Amount Remainder of 2015 $ 928 2016 1,679 2017 1,164 2018 703 2019 309 Thereafter 1,314 Total $ 6,097

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Stockholders' Equity	9. STOCKHOLDERS’ EQUITY A summary of the changes in stockholders’ equity for the six months ended June 30, 2015 is as follows: (In thousands) Stockholders’ Balance, December 31, 2014 $ 549,013 Net income 5,861 Dividend payments (9,509 ) Dividends accrued for unvested restricted stock units 10 Net unrealized losses on available-for-sale securities (net of tax) (2,286 ) Defined benefit plan adjustments 140 Foreign currency translation adjustment (2,446 ) Proceeds from stock option exercises 833 Purchase of treasury stock (49,307 ) Income tax benefit from exercise of stock options (23 ) Stock-based compensation expense 3,114 Balance, June 30, 2015 $ 495,400 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 45.0 million shares of our common stock. During the six months ended June 30, 2015, we repurchased 2.9 million shares of our common stock at an average price of $16.87 per share. As of June 30, 2015, we have the authority to purchase an additional 1.9 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 six months ended June 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 $0.8 million from the exercise of these stock options during the six months ended June 30, 2015. Dividend Payments During the six months ended June 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 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 June 30, 2015 and 2014: Three Months Ended June 30, 2015 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 8,461 $ (5,689 ) $ (6,600 ) $ (3,828 ) Other comprehensive income (loss) before reclassifications 177 — 872 1,049 Amounts reclassified from accumulated other comprehensive income (1,960 ) 72 — (1,888 ) Net current period other comprehensive income (loss) (1,783 ) 72 872 (839 ) Ending balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Three Months Ended June 30, 2014 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 9,816 $ (891 ) $ 1,159 $ 10,084 Other comprehensive income (loss) before reclassifications 2,516 — 134 2,650 Amounts reclassified from accumulated other comprehensive income (1,297 ) — — (1,297 ) Net current period other comprehensive income (loss) 1,219 — 134 1,353 Ending balance $ 11,035 $ (891 ) $ 1,293 $ 11,437 The following tables present changes in accumulated other comprehensive income, net of tax, by component for the six months ended June 30, 2015 and 2014: Six Months Ended June 30, 2015 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Foreign Total Beginning balance $ 8,964 $ (5,757 ) $ (3,282 ) $ (75 ) Other comprehensive income (loss) before reclassifications 1,537 — (2,446 ) (909 ) Amounts reclassified from accumulated other comprehensive income (3,823 ) 140 — (3,683 ) Net current period other comprehensive income (loss) (2,286 ) 140 (2,446 ) (4,592 ) Ending balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Six Months Ended June 30, 2014 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 10,737 $ (891 ) $ 907 $ 10,753 Other comprehensive income (loss) before reclassifications 2,918 — 386 3,304 Amounts reclassified from accumulated other comprehensive income (2,620 ) — — (2,620 ) Net current period other comprehensive income (loss) 298 — 386 684 Ending balance $ 11,035 $ (891 ) $ 1,293 $ 11,437 The following tables present the details of reclassifications out of accumulated other comprehensive income for the three months ended June 30, 2015 and 2014: (In thousands) Three Months Ended June 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 3,264 Net realized investment gain Impairment expense (51 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (105 ) (1) Total reclassifications for the period, before tax 3,108 Tax (expense) benefit (1,220 ) Total reclassifications for the period, net of tax $ 1,888 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Three Months Ended June 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 2,160 Net realized investment gain Impairment expense (34 ) Net realized investment gain Total reclassifications for the period, before tax 2,126 Tax (expense) benefit (829 ) Total reclassifications for the period, net of tax $ 1,297 The following tables present the details of reclassifications out of accumulated other comprehensive income for the six months ended June 30, 2015 and 2014: (In thousands) Six Months Ended June 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 6,340 Net realized investment gain Impairment expense (73 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (203 ) (1) Total reclassifications for the period, before tax 6,064 Tax (expense) benefit (2,381 ) Total reclassifications for the period, net of tax $ 3,683 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Six Months Ended June 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 4,330 Net realized investment gain Impairment expense (34 ) Net realized investment gain Total reclassifications for the period, before tax 4,296 Tax (expense) benefit (1,676 ) Total reclassifications for the period, net of tax $ 2,620 The following table presents the tax effects related to the change in each component of other comprehensive income for the three months ended June 30, 2015 and 2014: Three Months Ended June 30, 2015 Three Months Ended June 30, 2014 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Benefit Net-of-Tax Unrealized gains (losses) on available-for-sale securities $ 290 $ (113 ) $ 177 $ 4,125 $ (1,609 ) $ 2,516 Reclassification adjustment for amounts included in net income (3,108 ) 1,220 (1,888 ) (2,126 ) 829 (1,297 ) Foreign currency translation adjustment 872 — 872 134 — 134 Total Other Comprehensive Income (Loss) $ (1,946 ) $ 1,107 $ (839 ) $ 2,133 $ (780 ) $ 1,353 The following table presents the tax effects related to the change in each component of other comprehensive income for the six months ended June 30, 2015 and 2014: Six Months Ended June 30, 2015 Six Months Ended June 30, 2014 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Benefit Net-of-Tax Unrealized gains (losses) on available-for-sale securities $ 2,520 $ (983 ) $ 1,537 $ 4,784 $ (1,866 ) $ 2,918 Reclassification adjustment for amounts included in net income (6,064 ) 2,381 (3,683 ) (4,296 ) 1,676 (2,620 ) Foreign currency translation adjustment (2,446 ) — (2,446 ) 386 — 386 Total Other Comprehensive Income (Loss) $ (5,990 ) $ 1,398 $ (4,592 ) $ 874 $ (190 ) $ 684

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014 is as follows: Three Months Ended June 30, Six Months Ended June 30, (In thousands, except per share amounts) 2015 2014 2015 2014 Numerator Net income $ 2,544 $ 14,395 $ 5,861 $ 24,002 Denominator Weighted average number of shares – basic 51,822 55,409 52,607 56,077 Effect of dilutive securities Stock options 72 288 122 459 Restricted stock and restricted stock units 23 32 13 23 Weighted average number of shares – diluted 51,917 55,729 52,742 56,559 Net income per share – basic $ 0.05 $ 0.26 $ 0.11 $ 0.43 Net income per share – diluted $ 0.05 $ 0.26 $ 0.11 $ 0.42 Anti-dilutive options to purchase common stock outstanding were excluded from the above calculations. Anti-dilutive options totaled 6.1 million and 4.3 million for the three months ended June 30, 2015 and 2014, respectively, and 5.7 million and 3.1 million for the six months ended June 30, 2015 and 2014, respectively.

Segment Information

Segment Information	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014. Asset information by reportable segment is not reported, since we do not produce such information internally. Three Months Ended June 30, 2015 June 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 135,397 $ 54,699 $ 143,455 $ 68,053 Enterprise Networks 24,741 13,547 32,674 18,744 Total $ 160,138 $ 68,246 $ 176,129 $ 86,797 Six Months Ended June 30, 2015 June 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 251,411 $ 104,558 $ 261,617 $ 129,406 Enterprise Networks 51,562 29,251 61,516 35,181 Total $ 302,973 $ 133,809 $ 323,133 $ 164,587 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 six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2015 2014 2015 2014 Carrier Systems $ 119,039 $ 128,824 $ 219,478 $ 228,377 Business Networking 34,210 41,969 69,591 79,888 Loop Access 6,889 5,336 13,904 14,868 Total $ 160,138 $ 176,129 $ 302,973 $ 323,133 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 six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2015 2014 2015 2014 Core Products Broadband Access (included in Carrier Systems) $ 100,746 $ 108,309 $ 185,540 $ 189,836 Optical (included in Carrier Systems) 16,432 15,833 28,936 28,622 Internetworking (included in Business Networking) 33,158 40,986 67,317 77,932 Subtotal 150,336 165,128 281,793 296,390 Legacy Products HDSL (does not include T1) (included in Loop Access) 6,399 4,798 13,102 13,675 Other products (excluding HDSL) 3,403 6,203 8,078 13,068 Subtotal 9,802 11,001 21,180 26,743 Total $ 160,138 $ 176,129 $ 302,973 $ 323,133

Liability for Warranty Returns

Liability for Warranty Returns	6 Months Ended
	Jun. 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 systems products. 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 $8.9 million at June 30, 2015 and $8.4 million at December 31, 2014. These liabilities are included in accrued expenses in the accompanying Consolidated Balance Sheets. A summary of warranty expense and write-off activity for the six months ended June 30, 2015 and 2014 is as follows: Six Months Ended June 30, 2015 2014 (In thousands) Balance at beginning of period $ 8,415 $ 8,977 Plus: Amounts charged to cost and expenses 1,128 1,339 Less: Deductions (610 ) (1,999 ) Balance at end of period $ 8,933 $ 8,317

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 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 six months ended June 30, 2014, we incurred fees of $10 thousand per month for these legal services.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 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 June 30, 2015, of which $7.7 million has been applied to these commitments.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	15. SUBSEQUENT EVENTS On July 14, 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 July 30, 2015. The payment date will be August 13, 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. On July 14, 2015, our Board of Directors authorized the repurchase of an additional 5.0 million shares of our common stock (bringing the total shares authorized for repurchase to 50.0 million), which will commence upon completion of the repurchase plan announced May 14, 2014. This new authorization will be implemented through open market or private purchases from time to time as conditions warrant. During the third quarter and as of August 5, 2015, we have repurchased 0.8 million shares of our common stock through open market purchases at an average cost of $16.31 per share. We currently have the authority to purchase an additional 6.0 million shares of our common stock under the current plan approved by the Board of Directors.

Summary of Significant Accoun22

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 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 six months ended June 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 In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory . Inventory,

Pension Benefit Plan (Tables)

Pension Benefit Plan (Tables)	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2015 2014 2015 2014 Service cost $ 324 $ 306 $ 664 $ 611 Interest cost 152 216 311 431 Expected return on plan assets (250 ) (280 ) (511 ) (559 ) Amortization of actuarial losses 100 — 205 — Net periodic pension cost $ 326 $ 242 $ 669 $ 483

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014, which was recognized as follows: Three Months Ended Six Months Ended (In thousands) 2015 2014 2015 2014 Stock-based compensation expense included in cost of sales $ 53 $ 119 $ 143 $ 235 Selling, general and administrative expense 723 1,015 1,414 2,041 Research and development expense 699 958 1,557 1,873 Stock-based compensation expense included in operating expenses 1,422 1,973 2,971 3,914 Total stock-based compensation expense 1,475 2,092 3,114 4,149 Tax benefit for expense associated with non-qualified options (222 ) (296 ) (402 ) (580 ) Total stock-based compensation expense, net of tax $ 1,253 $ 1,796 $ 2,712 $ 3,569
Summary of Weighted-Average Assumptions and Value of Options Granted	The weighted-average assumptions and value of options granted for the six months ended June 30, 2015 and 2014 are as follows: Six Months Ended June 30, June 30, Expected volatility 38.75 % 39.57 % Risk-free interest rate 1.46 % 1.86 % Expected dividend yield 1.60 % 1.38 % Expected life (in years) 6.47 6.25 Weighted-average estimated value $ 7.63 $ 9.28
Summary of Stock Options Outstanding	The following table is a summary of our stock options outstanding as of December 31, 2014 and June 30, 2015 and the changes that occurred during the six months ended June 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 2 $ 22.56 Options forfeited (243 ) $ 21.01 Options expired (157 ) $ 26.78 Options exercised (52 ) $ 16.08 Options outstanding, June 30, 2015 6,531 $ 23.70 5.92 $ 446 Options vested and expected to vest, June 30, 2015 6,440 $ 23.75 5.85 $ 331 Options exercisable, June 30, 2015 4,190 $ 25.21 4.51 $ 446

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Securities and Investments, Recorded at Either Fair Value or Cost	At June 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 $ 14,046 $ 2,601 $ (113 ) $ 16,534 Corporate bonds 114,446 123 (139 ) 114,430 Municipal fixed-rate bonds 67,302 130 (45 ) 67,387 Municipal variable rate demand notes 3,695 — — 3,695 Marketable equity securities 28,901 9,265 (866 ) 37,300 Available-for-sale securities held at fair value $ 228,390 $ 12,119 $ (1,163 ) $ 239,346 Restricted investment held at cost 30,000 Other investments held at cost 1,446 Total carrying value of available-for-sale investments $ 270,792 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 and Municipal Fixed-Rate Bonds	As of June 30, 2015, our corporate bonds and municipal fixed-rate bonds had the following contractual maturities: (In thousands) Corporate Municipal Less than one year $ 32,179 $ 18,254 One to two years 42,510 35,462 Two to three years 39,741 12,460 Three to five years — 1,211 Total $ 114,430 $ 67,387
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 Six Months Ended (In thousands) 2015 2014 2015 2014 Gross realized gains $ 3,459 $ 2,407 $ 6,604 $ 4,635 Gross realized losses $ (204 ) $ (67 ) $ (234 ) $ (103 )
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 June 30, 2015 Using (In thousands) Fair Value Quoted Prices (Level 1) Significant (Level 2) Significant (Level 3) Cash equivalents Money market funds $ 1,087 $ 1,087 $ — $ — Available-for-sale securities Deferred compensation plan assets 16,534 16,534 — — Available-for-sale debt securities Corporate bonds 114,430 — 114,430 — Municipal fixed-rate bonds 67,387 — 67,387 — Municipal variable rate demand notes 3,695 — 3,695 — Available-for-sale marketable equity securities Marketable equity securities – technology industry 7,786 7,786 — — Marketable equity securities – other 29,514 29,514 — — Available-for-sale securities 239,346 53,834 185,512 — Total $ 240,433 $ 54,921 $ 185,512 $ — Fair Value Measurements at December 31, 2014 Using (In thousands) Fair Value Quoted Prices (Level 1) Significant (Level 2) Significant (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)	6 Months Ended
	Jun. 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 June 30, 2015 and December 31, 2014 were as follows: (In thousands) Balance Sheet June 30, 2015 December 31, Derivatives Not Designated as Hedging Instruments (Level 2): Foreign exchange contracts – asset derivatives Other receivables $ 447 $ 249 Foreign exchange contracts – liability derivatives Accounts payable $ (832 ) $ (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 six months ended June 30, 2015 and 2014 were as follows: Three Months Ended Six Months Ended Income Statement June 30, June 30, (In thousands) 2015 2014 2015 2014 Derivatives Not Designated as Hedging Instruments: Foreign exchange contracts Other income (expense) $ (1,299 ) $ (438 ) $ 177 $ (548 )

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Jun. 30, 2015
Inventory Disclosure [Abstract]
Components of Inventory	At June 30, 2015 and December 31, 2014, inventory consisted of the following: (In thousands) June 30, December 31, Raw materials $ 38,819 $ 34,831 Work in process 3,489 3,750 Finished goods 57,740 48,129 Total $ 100,048 $ 86,710

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	The following table presents our intangible assets as of June 30, 2015 and December 31, 2014: (In thousands) June 30, 2015 December 31, 2014 Gross Accumulated Net Gross Accumulated Net Customer relationships $ 5,937 $ (2,350 ) $ 3,587 $ 6,310 $ (2,136 ) $ 4,174 Developed technology 5,784 (3,962 ) 1,822 6,005 (3,577 ) 2,428 Intellectual property 2,340 (1,687 ) 653 2,340 (1,520 ) 820 Trade names 270 (235 ) 35 270 (205 ) 65 Other 11 (11 ) — 12 (11 ) 1 Total $ 14,342 $ (8,245 ) $ 6,097 $ 14,937 $ (7,449 ) $ 7,488
Estimated Future Amortization Expense Related to Intangible Asset	As of June 30, 2015, the estimated future amortization expense of our intangible assets is as follows: (In thousands) Amount Remainder of 2015 $ 928 2016 1,679 2017 1,164 2018 703 2019 309 Thereafter 1,314 Total $ 6,097

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2015
Equity [Abstract]
Summary of Changes in Stockholders' Equity	A summary of the changes in stockholders’ equity for the six months ended June 30, 2015 is as follows: (In thousands) Stockholders’ Balance, December 31, 2014 $ 549,013 Net income 5,861 Dividend payments (9,509 ) Dividends accrued for unvested restricted stock units 10 Net unrealized losses on available-for-sale securities (net of tax) (2,286 ) Defined benefit plan adjustments 140 Foreign currency translation adjustment (2,446 ) Proceeds from stock option exercises 833 Purchase of treasury stock (49,307 ) Income tax benefit from exercise of stock options (23 ) Stock-based compensation expense 3,114 Balance, June 30, 2015 $ 495,400
Cash Dividends	During the six months ended June 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
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 June 30, 2015 and 2014: Three Months Ended June 30, 2015 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 8,461 $ (5,689 ) $ (6,600 ) $ (3,828 ) Other comprehensive income (loss) before reclassifications 177 — 872 1,049 Amounts reclassified from accumulated other comprehensive income (1,960 ) 72 — (1,888 ) Net current period other comprehensive income (loss) (1,783 ) 72 872 (839 ) Ending balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Three Months Ended June 30, 2014 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 9,816 $ (891 ) $ 1,159 $ 10,084 Other comprehensive income (loss) before reclassifications 2,516 — 134 2,650 Amounts reclassified from accumulated other comprehensive income (1,297 ) — — (1,297 ) Net current period other comprehensive income (loss) 1,219 — 134 1,353 Ending balance $ 11,035 $ (891 ) $ 1,293 $ 11,437 The following tables present changes in accumulated other comprehensive income, net of tax, by component for the six months ended June 30, 2015 and 2014: Six Months Ended June 30, 2015 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Foreign Total Beginning balance $ 8,964 $ (5,757 ) $ (3,282 ) $ (75 ) Other comprehensive income (loss) before reclassifications 1,537 — (2,446 ) (909 ) Amounts reclassified from accumulated other comprehensive income (3,823 ) 140 — (3,683 ) Net current period other comprehensive income (loss) (2,286 ) 140 (2,446 ) (4,592 ) Ending balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Six Months Ended June 30, 2014 (In thousands) Unrealized Defined Foreign Total Beginning balance $ 10,737 $ (891 ) $ 907 $ 10,753 Other comprehensive income (loss) before reclassifications 2,918 — 386 3,304 Amounts reclassified from accumulated other comprehensive income (2,620 ) — — (2,620 ) Net current period other comprehensive income (loss) 298 — 386 684 Ending balance $ 11,035 $ (891 ) $ 1,293 $ 11,437
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 June 30, 2015 and 2014: (In thousands) Three Months Ended June 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 3,264 Net realized investment gain Impairment expense (51 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (105 ) (1) Total reclassifications for the period, before tax 3,108 Tax (expense) benefit (1,220 ) Total reclassifications for the period, net of tax $ 1,888 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Three Months Ended June 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 2,160 Net realized investment gain Impairment expense (34 ) Net realized investment gain Total reclassifications for the period, before tax 2,126 Tax (expense) benefit (829 ) Total reclassifications for the period, net of tax $ 1,297 The following tables present the details of reclassifications out of accumulated other comprehensive income for the six months ended June 30, 2015 and 2014: (In thousands) Six Months Ended June 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 6,340 Net realized investment gain Impairment expense (73 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (203 ) (1) Total reclassifications for the period, before tax 6,064 Tax (expense) benefit (2,381 ) Total reclassifications for the period, net of tax $ 3,683 (1) Included in the computation of net periodic pension cost. See Note 3 of Notes to Consolidated Financial Statements. (In thousands) Six Months Ended June 30, 2014 Details about Accumulated Other Comprehensive Income Components Amount Reclassified Affected Line Item in the Income Is Presented Unrealized gains (losses) on available-for-sale securities: Net realized gain on sales of securities $ 4,330 Net realized investment gain Impairment expense (34 ) Net realized investment gain Total reclassifications for the period, before tax 4,296 Tax (expense) benefit (1,676 ) Total reclassifications for the period, net of tax $ 2,620
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 June 30, 2015 and 2014: Three Months Ended June 30, 2015 Three Months Ended June 30, 2014 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Benefit Net-of-Tax Unrealized gains (losses) on available-for-sale securities $ 290 $ (113 ) $ 177 $ 4,125 $ (1,609 ) $ 2,516 Reclassification adjustment for amounts included in net income (3,108 ) 1,220 (1,888 ) (2,126 ) 829 (1,297 ) Foreign currency translation adjustment 872 — 872 134 — 134 Total Other Comprehensive Income (Loss) $ (1,946 ) $ 1,107 $ (839 ) $ 2,133 $ (780 ) $ 1,353 The following table presents the tax effects related to the change in each component of other comprehensive income for the six months ended June 30, 2015 and 2014: Six Months Ended June 30, 2015 Six Months Ended June 30, 2014 (In thousands) Before-Tax Tax Net-of-Tax Before-Tax Tax Benefit Net-of-Tax Unrealized gains (losses) on available-for-sale securities $ 2,520 $ (983 ) $ 1,537 $ 4,784 $ (1,866 ) $ 2,918 Reclassification adjustment for amounts included in net income (6,064 ) 2,381 (3,683 ) (4,296 ) 1,676 (2,620 ) Foreign currency translation adjustment (2,446 ) — (2,446 ) 386 — 386 Total Other Comprehensive Income (Loss) $ (5,990 ) $ 1,398 $ (4,592 ) $ 874 $ (190 ) $ 684

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014 is as follows: Three Months Ended June 30, Six Months Ended June 30, (In thousands, except per share amounts) 2015 2014 2015 2014 Numerator Net income $ 2,544 $ 14,395 $ 5,861 $ 24,002 Denominator Weighted average number of shares – basic 51,822 55,409 52,607 56,077 Effect of dilutive securities Stock options 72 288 122 459 Restricted stock and restricted stock units 23 32 13 23 Weighted average number of shares – diluted 51,917 55,729 52,742 56,559 Net income per share – basic $ 0.05 $ 0.26 $ 0.11 $ 0.43 Net income per share – diluted $ 0.05 $ 0.26 $ 0.11 $ 0.42

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014. Asset information by reportable segment is not reported, since we do not produce such information internally. Three Months Ended June 30, 2015 June 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 135,397 $ 54,699 $ 143,455 $ 68,053 Enterprise Networks 24,741 13,547 32,674 18,744 Total $ 160,138 $ 68,246 $ 176,129 $ 86,797 Six Months Ended June 30, 2015 June 30, 2014 (In thousands) Sales Gross Profit Sales Gross Profit Carrier Networks $ 251,411 $ 104,558 $ 261,617 $ 129,406 Enterprise Networks 51,562 29,251 61,516 35,181 Total $ 302,973 $ 133,809 $ 323,133 $ 164,587
Sales Information by Product Category	The table below presents sales information by product category for the three and six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2015 2014 2015 2014 Carrier Systems $ 119,039 $ 128,824 $ 219,478 $ 228,377 Business Networking 34,210 41,969 69,591 79,888 Loop Access 6,889 5,336 13,904 14,868 Total $ 160,138 $ 176,129 $ 302,973 $ 323,133
Subcategory Revenues	The table below presents subcategory revenues for the three and six months ended June 30, 2015 and 2014: Three Months Ended June 30, Six Months Ended June 30, (In thousands) 2015 2014 2015 2014 Core Products Broadband Access (included in Carrier Systems) $ 100,746 $ 108,309 $ 185,540 $ 189,836 Optical (included in Carrier Systems) 16,432 15,833 28,936 28,622 Internetworking (included in Business Networking) 33,158 40,986 67,317 77,932 Subtotal 150,336 165,128 281,793 296,390 Legacy Products HDSL (does not include T1) (included in Loop Access) 6,399 4,798 13,102 13,675 Other products (excluding HDSL) 3,403 6,203 8,078 13,068 Subtotal 9,802 11,001 21,180 26,743 Total $ 160,138 $ 176,129 $ 302,973 $ 323,133

Liability for Warranty Returns

Liability for Warranty Returns (Tables)	6 Months Ended
	Jun. 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 six months ended June 30, 2015 and 2014 is as follows: Six Months Ended June 30, 2015 2014 (In thousands) Balance at beginning of period $ 8,415 $ 8,977 Plus: Amounts charged to cost and expenses 1,128 1,339 Less: Deductions (610 ) (1,999 ) Balance at end of period $ 8,933 $ 8,317

Summary of Significant Accoun33

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2015	Jun. 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)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Effective tax rate	39.10%	34.20%

Pension Benefit Plan - Summariz

Pension Benefit Plan - Summarization of Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 324	$ 306	$ 664	$ 611
Interest cost	152	216	311	431
Expected return on plan assets	(250)	(280)	(511)	(559)
Amortization of actuarial losses	100		205
Net periodic pension cost	$ 326	$ 242	$ 669	$ 483

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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,475	$ 2,092	$ 3,114	$ 4,149
Tax benefit for expense associated with non-qualified options	(222)	(296)	(402)	(580)
Total stock-based compensation expense, net of tax	1,253	1,796	2,712	3,569
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	53	119	143	235
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	723	1,015	1,414	2,041
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	699	958	1,557	1,873
Operating Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,422	$ 1,973	$ 2,971	$ 3,914

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, granted	0	0	2,000
Estimated forfeitures for stock options			3.30%
Compensation expense related to non-vested stock options, RSUs and restricted stock not yet recognized	$ 12,600		$ 12,600
Recognition period of non-vested compensation cost			2 years 6 months
Total pre-tax intrinsic value of options exercised	$ 25		$ 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	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	38.75%	39.57%
Risk-free interest rate	1.46%	1.86%
Expected dividend yield	1.60%	1.38%
Expected life (in years)	6 years 5 months 19 days	6 years 3 months
Weighted-average estimated value	$ 7.63	$ 9.28

Stock-Based Compensation - Su39

Stock-Based Compensation - Summary of Stock Options Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 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	0	2,000
Number of Options, forfeited			(243,000)
Number of Options, expired			(157,000)
Number of Options, exercised			(52,000)
Number of Options, outstanding, Ending Balance	6,531,000		6,531,000	6,981,000
Number of Options, vested and expected to vest, Ending Balance	6,440,000		6,440,000
Number of Options, Options exercisable	4,190,000		4,190,000
Weighted Average Exercise Price, outstanding, Beginning Balance			$ 23.62
Weighted Average Exercise Price, granted			22.56
Weighted Average Exercise Price, forfeited			21.01
Weighted Average Exercise Price, expired			26.78
Weighted Average Exercise Price, exercised			16.08
Weighted Average Exercise Price, outstanding, Ending Balance	$ 23.70		23.70	$ 23.62
Weighted Average Exercise Price, vested and expected to vest, Ending Balance	23.75		23.75
Weighted Average Exercise Price, Options exercisable	$ 25.21		$ 25.21
Weighted Average Remaining Contractual Life In Years, Options outstanding			5 years 11 months 1 day	6 years 5 months 12 days
Weighted Average Remaining Contractual Life In Years, Options vested and expected to vest			5 years 10 months 6 days
Weighted Average Remaining Contractual Life In Years, Options exercisable			4 years 6 months 4 days
Aggregate Intrinsic Value, Options outstanding, Ending Balance	$ 446		$ 446
Aggregate Intrinsic Value, Options vested and expected to vest	331		331
Aggregate Intrinsic Value, Options exercisable	$ 446		$ 446

Investments - Securities and In

Investments - Securities and Investments, Recorded at Either Fair Value or Cost (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 228,390	$ 281,363
Gross Unrealized Gains	12,119	15,470
Gross Unrealized Losses	(1,163)	(771)
Available-for-sale-securities, Carrying Value	239,346	296,062
Restricted investment held at cost	30,000	30,000
Other investments held at cost	1,446	1,506
Total carrying value of available-for-sale investments	270,792	327,568
Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,046	13,897
Gross Unrealized Gains	2,601	2,409
Gross Unrealized Losses	(113)	(12)
Available-for-sale-securities, Carrying Value	16,534	16,294
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	114,446	111,261
Gross Unrealized Gains	123	186
Gross Unrealized Losses	(139)	(186)
Available-for-sale-securities, Carrying Value	114,430	111,261
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	67,302	127,341
Gross Unrealized Gains	130	480
Gross Unrealized Losses	(45)	(34)
Available-for-sale-securities, Carrying Value	67,387	127,787
Municipal Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,695	2,465
Available-for-sale-securities, Carrying Value	3,695	2,465
Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,901	26,399
Gross Unrealized Gains	9,265	12,395
Gross Unrealized Losses	(866)	(539)
Available-for-sale-securities, Carrying Value	$ 37,300	$ 38,255

Investments - Contractual Matur

Investments - Contractual Maturities of Corporate Bonds and Municipal Fixed-Rate Bonds (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale-securities, Fair Value/Carrying Value	$ 239,346	$ 296,062
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	32,179
One to two years	42,510
Two to three years	39,741
Available-for-sale-securities, Fair Value/Carrying Value	114,430	111,261
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	18,254
One to two years	35,462
Two to three years	12,460
Three to five years	1,211
Available-for-sale-securities, Fair Value/Carrying Value	$ 67,387	$ 127,787

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 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	$ 29,900
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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Investments, Debt and Equity Securities [Abstract]
Gross realized gains	$ 3,459	$ 2,407	$ 6,604	$ 4,635
Gross realized losses	$ (204)	$ (67)	$ (234)	$ (103)

Investments - Fair Value Measur

Investments - Fair Value Measurements of Cash Equivalents Held in Money Market Funds and Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 239,346	$ 296,062
Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	16,534	16,294
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	114,430	111,261
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	67,387	127,787
Municipal Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	3,695	2,465
Fair Value, Measurements, Recurring [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	239,346	296,062
Total	240,433	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	53,834	54,549
Total	54,921	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	185,512	241,513
Total	185,512	241,513
Fair Value, Measurements, Recurring [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	1,087	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	1,087	1,163
Fair Value, Measurements, Recurring [Member] | Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	16,534	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	16,534	16,294
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	114,430	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	114,430	111,261
Fair Value, Measurements, Recurring [Member] | Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	67,387	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	67,387	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	3,695	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	3,695	2,465
Fair Value, Measurements, Recurring [Member] | Marketable Equity Securities - Technology Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	7,786	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	7,786	9,661
Fair Value, Measurements, Recurring [Member] | Marketable Equity Securities - Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	29,514	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	$ 29,514	$ 28,594

Derivative Instruments and He45

Derivative Instruments and Hedging Activities - Additional Information (Detail) - Jun. 30, 2015	USD ($)	EUR (€)
Derivative [Line Items]
Maximum contractual period for derivatives	12 months
Forward Contracts [Member]
Derivative [Line Items]
Derivative, notional amount	$ 43,400,000	€ 39,000,000
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	Jun. 30, 2015	Dec. 31, 2014
Other Receivables [Member]
Derivatives Not Designated as Hedging Instruments (Level 2):
Derivatives asset, fair value	$ 447	$ 249
Accounts Payable [Member]
Derivatives Not Designated as Hedging Instruments (Level 2):
Derivatives liability, fair value	$ (832)	$ (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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Foreign Exchange Contracts [Member] | Other Income (Expense) [Member]
Derivatives Not Designated as Hedging Instruments:
Derivative instrument, gain or loss	$ (1,299)	$ (438)	$ 177	$ (548)

Inventory - Components of Inven

Inventory - Components of Inventory (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 38,819	$ 34,831
Work in process	3,489	3,750
Finished goods	57,740	48,129
Total	$ 100,048	$ 86,710

Inventory - Additional Informat

Inventory - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Raw Materials [Member]
Inventory [Line Items]
Inventory valuation reserves	$ 17.6	$ 16.9
Finished Goods [Member]
Inventory [Line Items]
Inventory valuation reserves	$ 7.6	$ 7.8

Goodwill and Intangible Asset50

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 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	$ 1,000,000	$ 1,200,000

Goodwill and Intangible Asset51

Goodwill and Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Goodwill [Line Items]
Gross Value	$ 14,342	$ 14,937
Accumulated Amortization	(8,245)	(7,449)
Net Value	6,097	7,488
Customer Relationships [Member]
Goodwill [Line Items]
Gross Value	5,937	6,310
Accumulated Amortization	(2,350)	(2,136)
Net Value	3,587	4,174
Developed Technology [Member]
Goodwill [Line Items]
Gross Value	5,784	6,005
Accumulated Amortization	(3,962)	(3,577)
Net Value	1,822	2,428
Intellectual Property [Member]
Goodwill [Line Items]
Gross Value	2,340	2,340
Accumulated Amortization	(1,687)	(1,520)
Net Value	653	820
Trade Names [Member]
Goodwill [Line Items]
Gross Value	270	270
Accumulated Amortization	(235)	(205)
Net Value	35	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	Jun. 30, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2015	$ 928
2,016	1,679
2,017	1,164
2,018	703
2,019	309
Thereafter	1,314
Net Value	$ 6,097	$ 7,488

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Changes in Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Equity [Abstract]
Beginning Balance			$ 549,013
Net Income	$ 2,544	$ 14,395	5,861	$ 24,002
Dividend payments			(9,509)
Dividends accrued for unvested restricted stock units			10
Net unrealized losses on available-for-sale securities (net of tax)	(1,783)	1,219	(2,286)	298
Defined benefit plan adjustments	72		140
Foreign currency translation adjustment	872	$ 134	(2,446)	386
Proceeds from stock option exercises			833	$ 1,781
Purchase of treasury stock			(49,307)
Income tax benefit from exercise of stock options			(23)
Stock-based compensation expense			3,114
Ending Balance	$ 495,400		$ 495,400

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchased, shares	2,900,000
Shares repurchased, average price per share	$ 16.87
Additional shares authorized for purchase	1,900,000
Number of Options, exercised	(52,000)
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	$ 833	$ 1,781
Predecessor [Member]
Equity, Class of Treasury Stock [Line Items]
Maximum shares authorized for repurchase, prior and new announcements and total after new announcement	45,000,000

Stockholders' Equity - Cash Div

Stockholders' Equity - Cash Dividends (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Dividends Payable [Line Items]
Record Date			Jul. 30, 2015
Payment Date			Aug. 13, 2015
Per Share Amount	$ 0.09	$ 0.09	$ 0.18	$ 0.18
Total Dividend Paid			$ 9,509	$ 10,137
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

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Accumulated Other Comprehensive Income, Net of Tax by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (3,828)	$ 10,084	$ (75)	$ 10,753
Other comprehensive income (loss) before reclassifications	1,049	2,650	(909)	3,304
Amounts reclassified from accumulated other comprehensive income	(1,888)	(1,297)	(3,683)	(2,620)
Other Comprehensive Income (Loss), net of tax	(839)	1,353	(4,592)	684
Ending balance	(4,667)	11,437	(4,667)	11,437
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	8,461	9,816	8,964	10,737
Other comprehensive income (loss) before reclassifications	177	2,516	1,537	2,918
Amounts reclassified from accumulated other comprehensive income	(1,960)	(1,297)	(3,823)	(2,620)
Other Comprehensive Income (Loss), net of tax	(1,783)	1,219	(2,286)	298
Ending balance	6,678	11,035	6,678	11,035
Defined Benefit Plan Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(5,689)	(891)	(5,757)	(891)
Amounts reclassified from accumulated other comprehensive income	72		140
Other Comprehensive Income (Loss), net of tax	72		140
Ending balance	(5,617)	(891)	(5,617)	(891)
Foreign Currency Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(6,600)	1,159	(3,282)	907
Other comprehensive income (loss) before reclassifications	872	134	(2,446)	386
Other Comprehensive Income (Loss), net of tax	872	134	(2,446)	386
Ending balance	$ (5,728)	$ 1,293	$ (5,728)	$ 1,293

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Income before provision for income taxes	$ 4,111	$ 21,811	$ 9,621	$ 36,490
Tax (expense) benefit	(1,567)	(7,416)	(3,760)	(12,488)
Total reclassifications for the period, net of tax	2,544	14,395	5,861	24,002
Reclassification Out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit plan adjustments - actuarial losses	(105)		(203)
Income before provision for income taxes	3,108	2,126	6,064	4,296
Tax (expense) benefit	(1,220)	(829)	(2,381)	(1,676)
Total reclassifications for the period, net of tax	1,888	1,297	3,683	2,620
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	3,264	2,160	6,340	4,330
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	$ (51)	$ (34)	$ (73)	$ (34)

Stockholders' Equity - Other Co

Stockholders' Equity - Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Equity [Abstract]
Unrealized gains (losses) on available-for-sale securities, Before-Tax Amount	$ 290	$ 4,125	$ 2,520	$ 4,784
Reclassification adjustment for amounts included in net income, Before-Tax Amount	(3,108)	(2,126)	(6,064)	(4,296)
Foreign currency translation adjustment, Before-Tax Amount	872	134	(2,446)	386
Total Other Comprehensive Income (Loss), Before-Tax Amount	(1,946)	2,133	(5,990)	874
Unrealized gains (losses) on available-for-sale securities, Tax (Expense) Benefit	(113)	(1,609)	(983)	(1,866)
Reclassification adjustment for amounts included in net income, Tax Benefit	1,220	829	2,381	1,676
Foreign currency translation adjustment, Tax Benefit	0	0	0	0
Total Other Comprehensive Income (Loss), Tax (Expense) Benefit	1,107	(780)	1,398	(190)
Unrealized gains (losses) on available-for-sale securities, Net-of-Tax Amount	177	2,516	1,537	2,918
Reclassification adjustment for amounts included in net income, Net-of-Tax Amount	(1,888)	(1,297)	(3,683)	(2,620)
Foreign currency translation adjustment, Net-of-Tax Amount	872	134	(2,446)	386
Other Comprehensive Income (Loss), net of tax	$ (839)	$ 1,353	$ (4,592)	$ 684

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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator
Net Income	$ 2,544	$ 14,395	$ 5,861	$ 24,002
Denominator
Weighted average number of shares - basic	51,822	55,409	52,607	56,077
Effect of dilutive securities
Stock options	72	288	122	459
Restricted stock and restricted stock units	23	32	13	23
Weighted average number of shares - diluted	51,917	55,729	52,742	56,559
Net income per share - basic	$ 0.05	$ 0.26	$ 0.11	$ 0.43
Net income per share - diluted	$ 0.05	$ 0.26	$ 0.11	$ 0.42

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Anti-dilutive options, Total	6.1	4.3	5.7	3.1

Segment Information - Additiona

Segment Information - Additional Information (Detail) - 6 months ended Jun. 30, 2015	SegmentProduct_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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Sales	$ 160,138	$ 176,129	$ 302,973	$ 323,133
Gross Profit	68,246	86,797	133,809	164,587
Carrier Networks [Member]
Segment Reporting Information [Line Items]
Sales	135,397	143,455	251,411	261,617
Gross Profit	54,699	68,053	104,558	129,406
Enterprise Networks [Member]
Segment Reporting Information [Line Items]
Sales	24,741	32,674	51,562	61,516
Gross Profit	$ 13,547	$ 18,744	$ 29,251	$ 35,181

Segment Information - Sales Inf

Segment Information - Sales Information by Product Category (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue from External Customer [Line Items]
Sales	$ 160,138	$ 176,129	$ 302,973	$ 323,133
Carrier Systems [Member]
Revenue from External Customer [Line Items]
Sales	119,039	128,824	219,478	228,377
Business Networking [Member]
Revenue from External Customer [Line Items]
Sales	34,210	41,969	69,591	79,888
Loop Access [Member]
Revenue from External Customer [Line Items]
Sales	$ 6,889	$ 5,336	$ 13,904	$ 14,868

Segment Information - Subcatego

Segment Information - Subcategory Revenues (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue from External Customer [Line Items]
Sales	$ 160,138	$ 176,129	$ 302,973	$ 323,133
Core Products [Member]
Revenue from External Customer [Line Items]
Sales	150,336	165,128	281,793	296,390
Legacy Products [Member]
Revenue from External Customer [Line Items]
Sales	9,802	11,001	21,180	26,743
Broadband Access (Included in Carrier Systems) [Member] | Core Products [Member]
Revenue from External Customer [Line Items]
Sales	100,746	108,309	185,540	189,836
Optical (Included in Carrier Systems) [Member] | Core Products [Member]
Revenue from External Customer [Line Items]
Sales	16,432	15,833	28,936	28,622
Internetworking (Included in Business Networking) [Member] | Core Products [Member]
Revenue from External Customer [Line Items]
Sales	33,158	40,986	67,317	77,932
HDSL (Does not Include T1) (Included in Loop Access) [Member] | Legacy Products [Member]
Revenue from External Customer [Line Items]
Sales	6,399	4,798	13,102	13,675
Other Products (Excluding HDSL) [Member] | Legacy Products [Member]
Revenue from External Customer [Line Items]
Sales	$ 3,403	$ 6,203	$ 8,078	$ 13,068

Liability for Warranty Return65

Liability for Warranty Returns - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Product Warranties Disclosures [Abstract]
Period of warranty for product defects	90 days to ten years
Liability for warranty obligations	$ 8,933	$ 8,415	$ 8,317	$ 8,977

Liability for Warranty Return66

Liability for Warranty Returns - Summary of Warranty Expense and Write-Off Activity (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Product Warranties Disclosures [Abstract]
Balance at beginning of period	$ 8,415	$ 8,977
Plus: Amounts charged to cost and expenses	1,128	1,339
Less: Deductions	(610)	(1,999)
Balance at end of period	$ 8,933	$ 8,317

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - Jun. 30, 2014 - USD ($) $ in Thousands	Total	Total
Director Emeritus [Member]
Related Party Transaction
Related party legal fees	$ 10	$ 10

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - Jun. 30, 2015 $ in Millions	USD ($)EquityUnit
Contingencies And Commitments [Line Items]
Aggregate investment committed in private equity funds	$ 7.9
Number of private equity funds | EquityUnit	2
Commitments towards private equity funds	$ 7.7
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	Aug. 05, 2015	Jul. 14, 2015	Jun. 30, 2015	Aug. 13, 2015
Subsequent Event [Line Items]
Dividend declaration date			Jul. 14, 2015
Dividend record date			Jul. 30, 2015
Dividend payment date			Aug. 13, 2015
Stock repurchased, shares			2,900,000
Shares repurchased, average price per share			$ 16.87
Additional shares authorized for purchase			1,900,000
Subsequent Events [Member]
Subsequent Event [Line Items]
Cash dividend per common share		$ 0.09
Cash dividend				$ 4.5
Number of shares authorized to be repurchased		5,000,000
Stock repurchased, shares	800,000
Shares repurchased, average price per share	$ 16.31
Additional shares authorized for purchase	6,000,000
Subsequent Events [Member] | Maximum [Member]
Subsequent Event [Line Items]
Number of shares authorized to be repurchased		50,000,000