ADTRAN (ADTN) 10-Q 8 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 20, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	ADTN
Entity Registrant Name	ADTRAN INC
Entity Central Index Key	926,282
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		48,398,164

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents	$ 66,292	$ 84,550
Short-term investments	55,516	34,396
Accounts receivable, less allowance for doubtful accounts of $- at September 30, 2016 and $19 at December 31, 2015	101,822	71,917
Other receivables	12,159	19,321
Income tax receivable, net	540
Inventory, net	96,034	91,533
Prepaid expenses and other current assets	14,477	10,145
Deferred tax assets, net	17,963	18,924
Total Current Assets	364,803	330,786
Property, plant and equipment, net	78,078	73,233
Deferred tax assets, net	17,263	18,091
Goodwill	3,492	3,492
Other assets	13,548	9,276
Long-term investments	178,379	198,026
Total Assets	655,563	632,904
Current Liabilities
Accounts payable	67,399	48,668
Unearned revenue	15,744	16,615
Accrued expenses	16,010	12,108
Accrued wages and benefits	16,468	12,857
Income tax payable, net		2,395
Total Current Liabilities	115,621	92,643
Non-current unearned revenue	7,105	7,965
Other non-current liabilities	26,740	24,236
Bonds payable	27,900	27,900
Total Liabilities	177,366	152,744
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 48,392 shares outstanding at September 30, 2016 and 79,652 shares issued and 49,558 shares outstanding at December 31, 2015	797	797
Additional paid-in capital	251,217	246,879
Accumulated other comprehensive loss	(7,826)	(8,969)
Retained earnings	920,395	906,772
Less treasury stock at cost: 31,260 and 30,094 shares at September 30, 2016 and December 31, 2015, respectively	(686,386)	(665,319)
Total Stockholders’ Equity	478,197	480,160
Total Liabilities and Stockholders’ Equity	$ 655,563	$ 632,904

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts		$ 19
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	48,392,000	49,558,000
Treasury stock, shares	31,260,000	30,094,000

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Sales
Products	$ 136,277	$ 138,120	$ 398,709	$ 411,723
Services	32,613	19,958	75,086	49,328
Total Sales	168,890	158,078	473,795	461,051
Cost of sales
Products	70,988	75,969	202,905	231,739
Services	22,094	11,460	50,333	24,854
Total Cost of Sales	93,082	87,429	253,238	256,593
Gross Profit	75,808	70,649	220,557	204,458
Selling, general and administrative expenses	33,716	30,016	97,367	93,203
Research and development expenses	31,962	32,561	92,727	100,576
Operating Income	10,130	8,072	30,463	10,679
Interest and dividend income	910	839	2,692	2,680
Interest expense	(143)	(151)	(430)	(448)
Net realized investment gain	1,316	2,060	4,154	8,430
Other income (expense), net	(246)	52	(378)	(848)
Gain on bargain purchase of a business	3,550		3,550
Income before provision for income taxes	15,517	10,872	40,051	20,493
Provision for income taxes	(3,102)	(3,805)	(12,394)	(7,565)
Net Income	$ 12,415	$ 7,067	$ 27,657	$ 12,928
Weighted average shares outstanding – basic	48,470	49,862	48,839	51,682
Weighted average shares outstanding – diluted	48,678	49,927	49,036	51,792
Earnings per common share – basic	$ 0.26	$ 0.14	$ 0.57	$ 0.25
Earnings per common share – diluted	0.26	0.14	0.56	0.25
Dividend per share	$ 0.09	$ 0.09	$ 0.27	$ 0.27

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 12,415	$ 7,067	$ 27,657	$ 12,928
Other Comprehensive Income (Loss), net of tax:
Net unrealized losses on available-for-sale securities	258	(4,291)	(162)	(6,577)
Defined benefit plan adjustments	36	71	103	211
Foreign currency translation	575	(1,351)	1,202	(3,797)
Other Comprehensive Income (Loss), net of tax	869	(5,571)	1,143	(10,163)
Comprehensive Income, net of tax	$ 13,284	$ 1,496	$ 28,800	$ 2,765

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 27,657	$ 12,928
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	10,260	10,765
Amortization of net premium on available-for-sale investments	489	2,085
Net realized investment gain	(4,154)	(8,430)
Net loss on disposal of property, plant and equipment	21	189
Gain on bargain purchase of a business	(3,550)
Stock-based compensation expense	4,601	4,788
Deferred income taxes	(447)	(2,332)
Tax benefit from stock option exercises	(16)	(40)
Excess tax benefits from stock-based compensation arrangements		(3)
Changes in operating assets and liabilities:
Accounts receivable, net	(29,370)	843
Other receivables	7,475	10,532
Inventory	(683)	(14,945)
Prepaid expenses and other assets	(5,180)	(1,665)
Accounts payable	16,363	13,687
Accrued expenses and other liabilities	7,307	(3,996)
Income tax payable/receivable, net	(2,941)	(1,137)
Net cash provided by operating activities	27,832	23,269
Cash flows from investing activities:
Purchases of property, plant and equipment	(12,684)	(7,843)
Proceeds from disposals of property, plant and equipment		122
Proceeds from sales and maturities of available-for-sale investments	141,103	189,728
Purchases of available-for-sale investments	(139,181)	(113,227)
Acquisition of business	(943)
Net cash provided by (used in) investing activities	(11,705)	68,780
Cash flows from financing activities:
Proceeds from stock option exercises	1,076	907
Purchases of treasury stock	(22,917)	(65,808)
Dividend payments	(13,230)	(13,989)
Excess tax benefits from stock-based compensation arrangements		3
Net cash used in financing activities	(35,071)	(78,887)
Net increase (decrease) in cash and cash equivalents	(18,944)	13,162
Effect of exchange rate changes	686	(2,914)
Cash and cash equivalents, beginning of period	84,550	73,439
Cash and cash equivalents, end of period	66,292	83,687
Supplemental disclosure of non-cash investing activities:
Purchases of property, plant and equipment included in accounts payable	$ 1,174	$ 1,303

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
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, 2015, filed on February 24, 2016 with the SEC. 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 (Topic 606) Revenue Recognition with early adoption permitted for reporting periods beginning after December 15, 2016. Subsequently, the FASB issued ASUs in 2016 containing implementation guidance related to ASU 2014-09, including: ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which is intended to improve the operability and understandability of the implementation guidance on principal versus agent considerations; ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , which is intended to clarify two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance; and ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , which contains certain provisions and practical expedients in response to identified implementation issues. In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory Inventory In November 2015, the FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting During the first quarter of 2016, we adopted the following accounting standards, which had no material effect on our financial position, results of operations or cash flows: 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

Business Combinations

Business Combinations	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Business Combinations	2. BUSINESS COMBINATIONS On September 13, 2016, we acquired key fiber access products, technologies and service relationships from subsidiaries of CommScope, Inc. for $0.9 million in cash. This acquisition will enhance our solutions for the cable MSO industry and will provide cable operators with the scalable solutions, services and support they require to compete in the multi-gigabit service delivery market. This transaction was accounted for as a business combination. We have included the financial results of this acquisition in our consolidated financial statements since the date of acquisition. These revenues are included in the Network Solutions reportable segment, and in the Access & Aggregation and Customer Devices categories. We recorded a bargain purchase gain of $3.6 million, net of income taxes, subject to customary working capital adjustments between the parties. The bargain purchase gain of $3.6 million represents the excess fair value of the net assets acquired over the consideration exchanged. We have assessed the recognition and measurement of the assets acquired and liabilities assumed based on historical and pro forma data for future periods and have concluded that our valuation procedures and resulting measures were appropriate. The gain is included in the line item “Gain on bargain purchase of a business” in the 2016 Consolidated Statements of Income. The preliminary allocation of the purchase price to the estimated fair value of the assets acquired and liabilities assumed at the acquisition date, subject to working capital adjustments, is as follows: (In Thousands) Assets Inventory 3,272 Property, plant and equipment 352 Intangible assets 4,700 Total assets acquired 8,324 Liabilities Accounts payable (1,378 ) Warranty payable (61 ) Accrued wages and benefits (122 ) Deferred income taxes (2,270 ) Total liabilities assumed (3,831 ) Total net assets 4,493 Gain on bargain purchase of a business, net of tax (3,550 ) Total purchase price $ 943 The details of the acquired intangible assets are as follows: In thousands Value Life (years) Supply agreement $ 1,400 0.8 Customer relationships 1,200 6 Developed technology 800 10 License 500 1.3 Patent 500 7.3 Non-compete 200 2.3 Trade name 100 2 Total $ 4,700 The actual revenue and pre-tax loss included in our Consolidated Statements of Income for the period September 13, 2016 to September 30, 2016 are as follows: September 13 to (In thousands) September 30, 2016 Revenue $ 1,291 Pre-tax loss $ (70 ) The following supplemental pro forma information presents the financial results as if the acquisition had occurred on January 1, 2015. This supplemental pro forma information does not purport to be indicative of what would have occurred had the acquisition been completed on January 1, 2015, nor is it indicative of any future results. Aside from revising the 2015 pre-tax income for the effect of the bargain purchase gain, there were no material, non-recurring adjustments to this pro forma information. Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Pro forma revenue $ 170,498 $ 159,375 $ 478,184 $ 463,916 Pro forma pre-tax income $ 11,778 $ 10,294 $ 35,771 $ 21,826 For the three months ended September 30, 2016, we incurred acquisition and integration related expenses and amortization of acquired intangibles of $0.2 million related to this acquisition.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	3. INCOME TAXES Our effective tax rate decreased from 36.9% in the nine months ended September 30, 2015 to 34.0%, excluding the tax impact of the bargain purchase gain, in the nine months ended September 30, 2016. The decrease in the effective tax rate between the two periods is primarily attributable to the research and development tax credit being made permanent.

Pension Benefit Plan

Pension Benefit Plan	9 Months Ended
	Sep. 30, 2016
Compensation And Retirement Disclosure [Abstract]
Pension Benefit Plan	4. PENSION BENEFIT PLAN We maintain a defined benefit pension plan covering employees in certain foreign countries. The following table summarizes the components of net periodic pension cost for the three and nine months ended September 30, 2016 and 2015: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Service cost $ 305 $ 328 $ 912 $ 992 Interest cost 182 153 542 464 Expected return on plan assets (266 ) (252 ) (796 ) (763 ) Amortization of actuarial losses 44 102 132 307 Net periodic pension cost $ 265 $ 331 $ 790 $ 1,000

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	5. STOCK-BASED COMPENSATION The following table summarizes the stock-based compensation expense related to stock options, restricted stock units (RSUs) and restricted stock for the three and nine months ended September 30, 2016 and 2015, which was recognized as follows: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Stock-based compensation expense included in cost of sales $ 88 $ 59 $ 282 $ 202 Selling, general and administrative expense 765 812 2,322 2,226 Research and development expense 639 803 1,997 2,360 Stock-based compensation expense included in operating expenses 1,404 1,615 4,319 4,586 Total stock-based compensation expense 1,492 1,674 4,601 4,788 Tax benefit for expense associated with non-qualified options (218 ) (218 ) (643 ) (620 ) Total stock-based compensation expense, net of tax $ 1,274 $ 1,456 $ 3,958 $ 4,168 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. The weighted-average assumptions and value of options granted during the three and nine months ended September 30, 2016 and 2015 are as follows: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Expected volatility 34.55 % 34.80 % 34.66 % 36.24 % Risk-free interest rate 1.20 % 1.84 % 1.28 % 1.70 % Expected dividend yield 1.83 % 2.13 % 1.88 % 1.94 % Expected life (in years) 6.21 6.24 6.24 6.32 Weighted-average estimated value $ 5.64 $ 4.89 $ 5.50 $ 5.89 The fair value of our RSUs is calculated using a Monte Carlo Simulation valuation method. No RSUs were granted or vested during the three and nine months ended September 30, 2016 and 2015. Twelve thousand RSUs were forfeited during the nine months ended September 30, 2015. The fair value of restricted stock is equal to the closing price of our stock on the date of grant. Two thousand shares and four thousand shares of restricted stock were granted during the three and nine months ended September 30, 2016, respectively. Two thousand shares of restricted stock vested during the three and nine months ended September 30, 2015. Stock-based compensation expense recognized in our Consolidated Statements of Income for the three and nine months ended September 30, 2016 and 2015 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 3.7% annually. We estimated a 0% forfeiture rate for our RSUs and restricted stock due to the limited number of recipients and historical experience for these awards. As of September 30, 2016, total compensation expense related to non-vested stock options, RSUs and restricted stock not yet recognized was approximately $9.9 million, which is expected to be recognized over an average remaining recognition period of 2.2 years. The following table is a summary of our stock options outstanding as of December 31, 2015 and September 30, 2016 and the changes that occurred during the nine months ended September 30, 2016: (In thousands, except per share amounts) Number of Options Weighted Avg. Exercise Price Weighted Avg. Remaining Contractual Life In Years Aggregate Intrinsic Value Options outstanding, December 31, 2015 7,108 $ 21.97 6.42 $ 3,284 Options granted 2 $ 19.19 Options exercised (65 ) $ 16.49 Options forfeited (78 ) $ 17.93 Options expired (142 ) $ 25.49 Options outstanding, September 30, 2016 6,825 $ 22.01 5.69 $ 7,675 Options vested and expected to vest, September 30, 2016 6,729 $ 22.09 5.65 $ 7,414 Options exercisable, September 30, 2016 4,322 $ 24.40 4.19 $ 2,719 The aggregate intrinsic values in the table above represent the total pre-tax intrinsic value (the difference between the closing price of our stock on the last trading day of the quarter and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had all option holders exercised their options on September 30, 2016. The aggregate intrinsic value will change based on the fair market value of our stock. The total pre-tax intrinsic value of options exercised during the three and nine months ended September 30, 2016 was $0.1 million and $0.2 million, respectively.

Investments

Investments	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Investments	6. INVESTMENTS At September 30, 2016, we held the following securities and investments, recorded at either fair value or cost. Amortized Gross Unrealized Carrying (In thousands) Cost Gains Losses Value Deferred compensation plan assets $ 11,656 $ 2,172 $ (20 ) $ 13,808 Corporate bonds 59,900 136 (50 ) 59,986 Municipal fixed-rate bonds 17,589 54 (4 ) 17,639 Asset-backed bonds 22,564 72 (23 ) 22,613 Mortgage/Agency-backed bonds 15,055 24 (43 ) 15,036 U.S. government bonds 28,437 168 - 28,605 Foreign government bonds 6,428 3 (1 ) 6,430 Variable rate demand notes 12,315 - - 12,315 Marketable equity securities 26,975 1,468 (1,076 ) 27,367 Available-for-sale securities held at fair value $ 200,919 $ 4,097 $ (1,217 ) $ 203,799 Restricted investment held at cost 28,900 Other investments held at cost 1,196 Total carrying value of available-for-sale investments $ 233,895 At December 31, 2015, we held the following securities and investments, recorded at either fair value or cost. Amortized Gross Unrealized Carrying (In thousands) Cost Gains Losses Value Deferred compensation plan assets $ 11,325 $ 1,575 $ (66 ) $ 12,834 Corporate bonds 58,328 20 (734 ) 57,614 Municipal fixed-rate bonds 26,414 28 (18 ) 26,424 Asset-backed bonds 19,281 2 (44 ) 19,239 Mortgage/Agency-backed bonds 15,463 1 (91 ) 15,373 U.S. Government bonds 35,646 - (248 ) 35,398 Marketable equity securities 31,643 4,301 (1,693 ) 34,251 Available-for-sale securities held at fair value $ 198,100 $ 5,927 $ (2,894 ) $ 201,133 Restricted investment held at cost 30,000 Other investments held at cost 1,289 Total carrying value of available-for-sale investments $ 232,422 As of September 30, 2016, our corporate bonds, municipal fixed-rate bonds, asset-backed bonds, mortgage/agency-backed bonds, U.S. government bonds, and foreign government bonds had the following contractual maturities: (In thousands) Corporate bonds Municipal fixed-rate bonds Asset- backed bonds Mortgage / Agency- backed bonds U.S. government bonds Foreign government bonds Less than one year $ 22,993 $ 12,156 $ - $ - $ 2,952 $ 5,100 One to two years 24,504 3,186 1,094 1,385 9,096 1,330 Two to three years 9,296 858 8,989 2,004 4,573 - Three to five years 3,193 1,439 9,739 - 11,984 - Five to ten years - - 2,614 1,448 - - More than ten years - - 177 10,199 - - Total $ 59,986 $ 17,639 $ 22,613 $ 15,036 $ 28,605 $ 6,430 Actual maturities may differ from contractual maturities because some borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Our investment policy provides limitations for issuer concentration, which limits, at the time of purchase, the concentration in any one issuer to 5% of the market value of our total investment portfolio. At September 30, 2016, we held a $28.9 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), which totaled $28.9 million at September 30, 2016 and December 31, 2015. At September 30, 2016, the estimated fair value of the Bond using a level 2 valuation technique was approximately $29.3 million, based on a debt security with a comparable interest rate and maturity and a Standard and Poor’s credit rating of AAA. We have the right to set-off the balance of the Bond with the collateral deposit in order to reduce the balance of the indebtedness. The Bond matures on January 1, 2020, and bears interest at the rate of 2% per annum. In conjunction with this program, we are eligible to receive certain economic incentives from the state of Alabama that reduce the amount of payroll withholdings we are required to remit to the state for those employment positions that qualify under this program. We are required to make payments in the amounts necessary to pay the interest on the amounts currently outstanding. It is our intent to make annual principal payments in addition to the interest amounts that are due. We review our investment portfolio for potential “other-than-temporary” declines in value on an individual investment basis. We assess, on a quarterly basis, significant declines in value which may be considered other-than-temporary and, if necessary, recognize and record the appropriate charge to write-down the carrying value of such investments. In making this assessment, we take into consideration qualitative and quantitative information, including but not limited to the following: the magnitude and duration of historical declines in market prices, credit rating activity, assessments of liquidity, public filings, and statements made by the issuer. We generally begin our identification of potential other-than-temporary impairments by reviewing any security with a fair value that has declined from its original or adjusted cost basis by 25% or more for six or more consecutive months. We then evaluate the individual security based on the previously identified factors to determine the amount of the write-down, if any. For the three and nine months ended September 30, 2016, 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 Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Gross realized gains $ 1,346 $ 2,251 $ 5,226 $ 8,856 Gross realized losses $ (30 ) $ (191 ) $ (1,072 ) $ (426 ) As of September 30, 2016 and 2015, gross unrealized losses related to individual securities in a continuous loss position for 12 months or longer were not significant. We have categorized our cash equivalents held in money market funds and our investments held at fair value into a three-level fair value hierarchy based on the priority of the inputs to the valuation technique for the cash equivalents and investments as follows: Level 1 - Values based on unadjusted quoted prices for identical assets or liabilities in an active market; Level 2 - Values based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly; Level 3 - Values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs include information supplied by investees. Fair Value Measurements at September 30, 2016 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 2,032 $ 2,032 $ - $ - Commercial Paper 3,585 - 3,585 - Cash equivalents 5,617 2,032 3,585 - Available-for-sale securities Deferred compensation plan assets 13,808 13,808 - - Available-for-sale debt securities Corporate bonds 59,986 - 59,986 - Municipal fixed-rate bonds 17,639 - 17,639 - Asset-backed bonds 22,613 - 22,613 - Mortgage/Agency-backed bonds 15,036 - 15,036 - U.S. government bonds 28,605 28,605 - - Foreign government bonds 6,430 - 6,430 - Variable rate demand notes 12,315 - 12,315 - Available-for-sale marketable equity securities Marketable equity securities – technology industry 3,693 3,693 - - Marketable equity securities – other 23,674 23,674 - - Available-for-sale securities 203,799 69,780 134,019 - Total $ 209,416 $ 71,812 $ 137,604 $ - Fair Value Measurements at December 31, 2015 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 1,271 $ 1,271 $ - $ - Commercial Paper 11,696 - 11,696 - Cash equivalents 12,967 1,271 11,696 - Available-for-sale securities Deferred compensation plan assets 12,834 12,834 - - Available-for-sale debt securities Corporate bonds 57,614 - 57,614 - Municipal fixed-rate bonds 26,424 - 26,424 - Asset-backed bonds 19,239 - 19,239 - Mortgage/Agency-backed bonds 15,373 - 15,373 - U.S. government bonds 35,398 35,398 - - Available-for-sale marketable equity securities Marketable equity securities – technology industry 5,384 5,384 - - Marketable equity securities – other 28,867 28,867 - - Available-for-sale securities 201,133 82,483 118,650 - Total $ 214,100 $ 83,754 $ 130,346 $ - 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 variable rate demand notes have a structure that implies a standard expected market price. The frequent interest rate resets make it reasonable to expect the price to stay at par. These securities are priced at the expected market price.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	7. 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, as these are remeasured to the functional currency through profit and loss. 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. Our derivative instruments are not subject to master netting arrangements and are not offset in the Consolidated Balance Sheets. As of September 30, 2016 and December 31, 2015, we had no forward contracts outstanding. The change in the fair values of our derivative instruments recorded in the Consolidated Statements of Income during the three and nine months ended September 30, 2016 and 2015 were as follows: Three Months Ended Nine Months Ended Income Statement September 30, September 30, (In thousands) Location 2016 2015 2016 2015 Derivatives Not Designated as Hedging Instruments: Foreign exchange contracts Other income (expense) $ (37 ) $ 30 $ 153 $ 208

Inventory

Inventory	9 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Inventory	8. INVENTORY At September 30, 2016 and December 31, 2015, inventory consisted of the following: September 30, December 31, (In thousands) 2016 2015 Raw materials $ 37,879 $ 34,223 Work in process 3,044 2,893 Finished goods 55,111 54,417 Total $ 96,034 $ 91,533 We establish reserves for estimated excess, obsolete, or unmarketable inventory equal to the difference between the cost of the inventory and the estimated fair value of the inventory based upon assumptions about future demand and market conditions. At September 30, 2016 and December 31, 2015, raw materials reserves totaled $18.3 million and $17.5 million, respectively, and finished goods inventory reserves totaled $10.1 million and $9.2 million, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	9. GOODWILL AND INTANGIBLE ASSETS Goodwill, all of which relates to our acquisition of Bluesocket, Inc., was $3.5 million at September 30, 2016 and December 31, 2015, and was previously recorded in our Enterprise Networks reportable segment. As a result of our new reporting structure, which is discussed further in Note 12, we reallocated goodwill from our Enterprise Networks reportable segment to our two, new reportable segments – Network Solutions and Services & Support. As a result, goodwill of $3.1 million and $0.4 million was reallocated to our Network Solutions and Services & Support reportable segments, respectively. 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. Based on the results of our qualitative assessment in 2015, we concluded that it was not necessary to perform the two-step impairment test. There have been no impairment losses recognized since the acquisition in 2011. 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, the NSN BBA business on May 4, 2012, and CommScope’s active fiber access business on September 13, 2016. The following table presents our intangible assets as of September 30, 2016 and December 31, 2015: (In thousands) September 30, 2016 December 31, 2015 Gross Value Accumulated Amortization Net Value Gross Value Accumulated Amortization Net Value Customer relationships $ 7,178 $ (3,147 ) 4,031 $ 5,828 $ (2,627 ) $ 3,201 Developed technology 6,609 (4,995 ) 1,614 5,720 (4,329 ) 1,391 Intellectual property 2,340 (2,096 ) 244 2,340 (1,854 ) 486 Supply agreement 1,400 (78 ) 1,322 - - - License 500 (16 ) 484 - - - Patent 500 (3 ) 497 - - - Trade names 370 (272 ) 98 270 (265 ) 5 Non-compete 200 (4 ) 196 11 (11 ) - Total $ 19,097 $ (10,611 ) $ 8,486 $ 14,169 $ (9,086 ) $ 5,083 Amortization expense, all of which relates to business acquisitions, was $0.5 million for the three months ended September 30, 2016 and 2015, and $1.4 million and $1.5 million for the nine months ended September 30, 2016 and 2015, respectively. As of September 30, 2016, the estimated future amortization expense of our intangible assets is as follows: (In thousands) Amount Remainder of 2016 $ 1,058 2017 2,901 2018 1,189 2019 675 2020 640 Thereafter 2,023 Total $ 8,486

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Stockholders' Equity	10. STOCKHOLDERS’ EQUITY A summary of the changes in stockholders’ equity for the nine months ended September 30, 2016 is as follows: (In thousands) Stockholders’ Equity Balance, December 31, 2015 $ 480,160 Net income 27,657 Dividend payments (13,230 ) Dividends accrued for unvested restricted stock units (30 ) Net unrealized losses on available-for-sale securities (net of tax) (162 ) Defined benefit plan adjustments 103 Foreign currency translation adjustment 1,202 Proceeds from stock option exercises 1,076 Purchase of treasury stock (22,917 ) Income tax effect of stock compensation arrangements (263 ) Stock-based compensation expense 4,601 Balance, September 30, 2016 $ 478,197 Stock Repurchase Program Since 1997, our Board of Directors has approved multiple share repurchase programs that have authorized open market repurchase transactions of up to 50.0 million shares of our common stock, which will be implemented through open market or private purchases from time to time as conditions warrant. During the nine months ended September 30, 2016, we repurchased 1.2 million shares of our common stock at an average price of $18.34 per share. As of September 30, 2016, we have the authority to purchase an additional 4.6 million shares of our common stock under the current plans approved by the Board of Directors. Stock Option Exercises We issued 0.1 million shares of treasury stock during the nine months ended September 30, 2016 to accommodate employee stock option exercises. The stock options had exercise prices ranging from $15.29 to $18.97. We received proceeds totaling $1.1 million from the exercise of these stock options during the nine months ended September 30, 2016. Dividend Payments During the nine months ended September 30, 2016, we paid cash dividends as follows (in thousands except per share amounts): Record Date Payment Date Per Share Amount Total Dividend Paid February 4, 2016 February 18, 2016 $ 0.09 $ 4,453 April 28, 2016 May 12, 2016 $ 0.09 $ 4,407 July 28, 2016 August 11, 2016 $ 0.09 $ 4,370 Other Comprehensive Income Other comprehensive income consists of unrealized gains (losses) on available-for-sale securities, reclassification adjustments for amounts included in net income related to impairments of available-for-sale securities, realized gains (losses) on available-for-sale securities, and amortization of actuarial gains (losses) related to our defined benefit plan, defined benefit plan adjustments, and foreign currency translation adjustments. The following tables present changes in accumulated other comprehensive income, net of tax, by component for the three months ended September 30, 2016 and 2015: Three Months Ended September 30, 2016 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 1,512 $ (3,828 ) $ (6,379 ) $ (8,695 ) Other comprehensive income (loss) before reclassifications 1,028 - 575 1,603 Amounts reclassified from accumulated other comprehensive income (770 ) 36 - (734 ) Net current period other comprehensive income (loss) 258 36 575 869 Ending balance $ 1,770 $ (3,792 ) $ (5,804 ) $ (7,826 ) Three Months Ended September 30, 2015 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Other comprehensive income (loss) before reclassifications (3,034 ) - (1,351 ) (4,385 ) Amounts reclassified from accumulated other comprehensive income (1,257 ) 71 - (1,186 ) Net current period other comprehensive income (loss) (4,291 ) 71 (1,351 ) (5,571 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 ) The following tables present changes in accumulated other comprehensive income, net of tax, by component for the nine months ended September 30, 2016 and 2015: Nine Months Ended September 30, 2016 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 1,932 $ (3,895 ) $ (7,006 ) $ (8,969 ) Other comprehensive income (loss) before reclassifications 2,267 - 1,202 3,469 Amounts reclassified from accumulated other comprehensive income (2,429 ) 103 - (2,326 ) Net current period other comprehensive income (loss) (162 ) 103 1,202 1,143 Ending balance $ 1,770 $ (3,792 ) $ (5,804 ) $ (7,826 ) Nine Months Ended September 30, 2015 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 8,964 $ (5,757 ) $ (3,282 ) $ (75 ) Other comprehensive income (loss) before reclassifications (1,497 ) - (3,797 ) (5,294 ) Amounts reclassified from accumulated other comprehensive income (5,080 ) 211 - (4,869 ) Net current period other comprehensive income (loss) (6,577 ) 211 (3,797 ) (10,163 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 ) The following tables present the details of reclassifications out of accumulated other comprehensive income for the three months ended September 30, 2016 and 2015: (In thousands) Three Months Ended September 30, 2016 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 1,268 Net realized investment gain Impairment expense (6 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (51 ) (1) Total reclassifications for the period, before tax 1,211 Tax (expense) benefit (477 ) Total reclassifications for the period, net of tax $ 734 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements. (In thousands) Three Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 2,098 Net realized investment gain Impairment expense (37 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (103 ) (1) Total reclassifications for the period, before tax 1,958 Tax (expense) benefit (772 ) Total reclassifications for the period, net of tax $ 1,186 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements. The following tables present the details of reclassifications out of accumulated other comprehensive income for the nine months ended September 30, 2016 and 2015: (In thousands) Nine Months Ended September 30, 2016 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 4,383 Net realized investment gain Impairment expense (401 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (149 ) (1) Total reclassifications for the period, before tax 3,833 Tax (expense) benefit (1,507 ) Total reclassifications for the period, net of tax $ 2,326 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements. (In thousands) Nine Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 8,438 Net realized investment gain Impairment expense (110 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (306 ) (1) Total reclassifications for the period, before tax 8,022 Tax (expense) benefit (3,153 ) Total reclassifications for the period, net of tax $ 4,869 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements. The following table presents the tax effects related to the change in each component of other comprehensive income for the three months ended September 30, 2016 and 2015: Three Months Ended Three Months Ended September 30, 2016 September 30, 2015 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Unrealized gains (losses) on available-for-sale securities $ 1,685 $ (657 ) $ 1,028 $ (4,974 ) $ 1,940 $ (3,034 ) Reclassification adjustment for amounts related to available-for-sale investments included in net income (1,262 ) 492 (770 ) (2,061 ) 804 (1,257 ) Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income 51 (15 ) 36 103 (32 ) 71 Foreign currency translation adjustment 575 - 575 (1,351 ) - (1,351 ) Total Other Comprehensive Income (Loss) $ 1,049 $ (180 ) $ 869 $ (8,283 ) $ 2,712 $ (5,571 ) The following table presents the tax effects related to the change in each component of other comprehensive income for the nine months ended September 30, 2016 and 2015: Nine Months Ended Nine Months Ended September 30, 2016 September 30, 2015 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Unrealized gains (losses) on available-for-sale securities $ 3,716 $ (1,449 ) $ 2,267 $ (2,454 ) $ 957 $ (1,497 ) Reclassification adjustment for amounts related to available-for-sale investments included in net income (3,982 ) 1,553 (2,429 ) (8,328 ) 3,248 (5,080 ) Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income 149 (46 ) 103 306 (95 ) 211 Foreign currency translation adjustment 1,202 - 1,202 (3,797 ) - (3,797 ) Total Other Comprehensive Income (Loss) $ 1,085 $ 58 $ 1,143 $ (14,273 ) $ 4,110 $ (10,163 )

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Earnings per Share	11. EARNINGS PER SHARE A summary of the calculation of basic and diluted earnings per share for the three and nine months ended September 30, 2016 and 2015 is as follows: Three Months Ended Nine Months Ended September 30, September 30, (In thousands, except per share amounts) 2016 2015 2016 2015 Numerator Net income $ 12,415 $ 7,067 $ 27,657 $ 12,928 Denominator Weighted average number of shares – basic 48,470 49,862 48,839 51,682 Effect of dilutive securities Stock options 137 29 137 94 Restricted stock and restricted stock units 71 36 60 16 Weighted average number of shares – diluted 48,678 49,927 49,036 51,792 Net income per share – basic $ 0.26 $ 0.14 $ 0.57 $ 0.25 Net income per share – diluted $ 0.26 $ 0.14 $ 0.56 $ 0.25 Anti-dilutive options to purchase common stock outstanding were excluded from the above calculations. Anti-dilutive options totaled 5.6 million and 6.0 million for the three months ended September 30, 2016 and 2015, respectively, and 5.7 million and 6.1 million for the nine months ended September 30, 2016 and 2015, respectively.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Segment Information	12. SEGMENT INFORMATION In 2015, we began a realignment of our organizational structure to better match our market opportunities, technological development initiatives, and improve efficiencies. During the first quarter of 2016, our chief operating decision maker requested changes in the information that he regularly reviews for purposes of allocating resources and assessing performance. As a result, beginning with the quarter ended March 31, 2016, we began reporting our financial performance based on two, new reportable segments – Network Solutions and Services & Support. Network Solutions includes hardware products and next-generation virtualized solutions used in service provider or business networks, as well as prior-generation products. Services & Support includes our suite of ProCloud ® We evaluate the performance of our new 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 a company-wide, functional basis only. Historical financial information by reportable segment and category, as discussed below, has been recast to conform to our new reporting structure. There are no inter-segment revenues. The following table presents information about the reported sales and gross profit of our reportable segments for the three and nine months ended September 30, 2016 and 2015. We do not produce asset information by reportable segment; therefore, it is not reported. Three Months Ended September 30, 2016 September 30, 2015 (In thousands) Sales Gross Profit Sales Gross Profit Network Solutions $ 136,277 $ 65,289 $ 138,120 $ 62,151 Services & Support 32,613 10,519 19,958 8,498 Total $ 168,890 $ 75,808 $ 158,078 $ 70,649 Nine Months Ended September 30, 2016 September 30, 2015 (In thousands) Sales Gross Profit Sales Gross Profit Network Solutions $ 398,709 $ 195,804 $ 411,723 $ 179,984 Services & Support 75,086 24,753 49,328 24,474 Total $ 473,795 $ 220,557 $ 461,051 $ 204,458 Sales by Category In addition to our new reporting segments, we will also report revenue for the following three categories – Access & Aggregation, Customer Devices, Traditional & Other Products. Access & Aggregation generally includes software and hardware based products and services that communication service providers (CSPs) use to aggregate and/or originate network access technologies. The portfolio of ADTRAN solutions within this category includes a wide array of modular or fixed physical form factors designed to deliver the best technology and economic fit for our customers based on the target subscriber density and environmental conditions. The Access & Aggregation category includes product and service families such as: • Total Access ® • hiX 5600 Series fiber aggregation and Fiber to the Node (FTTN) Multi-Service Access Nodes (MSAN) • A9000 Series of EPON DOCSIS-provisioned Optical Line Terminals (OLT) • Fiber to the Distribution Point (FTTdp) Optical Network Units (ONU) • Optical Line Terminals (OLT) • Optical Networking Edge (ONE) aggregation • Distribution Point Units (DPUs) • IP Digital Subscriber Line Access Multiplexers (DSLAMs) • Cabinet and Outside-Plant (OSP) enclosures and services • Network Management and Cloud based software platforms and applications • Pluggable optical transceivers (i.e., SFP, SFP+, XFP, QSFP), cables and other miscellaneous materials • Other products and services that are generally applicable to Access & Aggregation Customer Devices generally includes the products and services that provide end users access to the CSP network. The Customer Devices portfolio includes a comprehensive array of service provider and enterprise hardware and software products and services. The Customer Devices category includes products and services such as: • Broadband customer premise solutions, including Passive Optical Network (PON) and point-to-point Ethernet Optical Network Terminals (ONTs) • Radio Frequency over Glass (RFoG) MicroNodes • Residential and business gateways • Wi-Fi access points and associated powering and switching infrastructure • enterprise Session Border Controllers (eSBC) • Branch office and access routers • Carrier Ethernet services termination devices • VoIP media gateways • ProServices ® • Planning, engineering, program management, maintenance, installation and commissioning services to implement the customer devices solutions into consumer, small business and enterprise locations • Other products and services that are generally applicable to customer devices Traditional & Other Products generally includes a mix of prior generation technologies’ products and services, as well as other products and services that do not fit within the Access & Aggregation or Customer Devices categories. The Traditional & Other Products category includes products and services such as: • Time Division Multiplexed (TDM) and Asynchronous Transfer Mode (ATM) based aggregation systems and customer devices • HDSL, ADSL and other mature technologies used to deliver business and residential services over the CSP access and customer networks • Other products and services that do not fit within the Access & Aggregation and Customer Devices categories The table below presents sales information by category for the three and nine months ended September 30, 2016 and 2015: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Access & Aggregation $ 120,618 $ 103,431 $ 316,705 $ 309,014 Customer Devices 32,984 35,545 106,213 97,291 Traditional & Other Products 15,288 19,102 50,877 54,746 Total $ 168,890 $ 158,078 $ 473,795 $ 461,051

Liability for Warranty Returns

Liability for Warranty Returns	9 Months Ended
	Sep. 30, 2016
Product Warranties Disclosures [Abstract]
Liability for Warranty Returns	13. LIABILITY FOR WARRANTY RETURNS Our products generally include warranties of 90 days to ten years for product defects. We accrue for warranty returns at the time revenue is recognized based on our estimate of the cost to repair or replace the defective products. We engage in extensive product quality programs and processes, including actively monitoring and evaluating the quality of our component suppliers. Our products continue to become more complex in both size and functionality as many of our product offerings migrate from line card applications to total systems. The increasing complexity of our products will cause warranty incidences, when they arise, to be more costly. Our estimates regarding future warranty obligations may change due to product failure rates, material usage, and other rework costs incurred in correcting a product failure. In addition, from time to time, specific warranty accruals may be recorded if unforeseen problems arise. Should our actual experience relative to these factors be worse than our estimates, we will be required to record additional warranty expense. Alternatively, if we provide for more reserves than we require, we will reverse a portion of such provisions in future periods. The liability for warranty obligations totaled $8.8 million and $8 . A summary of warranty expense and write-off activity for the three and nine months ended September 30, 2016 and 2015 is as follows: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Balance at beginning of period $ 8,935 $ 8,933 $ 8,739 $ 8,415 Plus: Amounts charged to cost and expenses 4,012 777 6,341 1,905 Less: Deductions (4,195 ) (994 ) (6,328 ) (1,604 ) Balance at end of period $ 8,752 $ 8,716 $ 8,752 $ 8,716

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. COMMITMENTS AND CONTINGENCIES In the ordinary course of business, we may be subject to various legal proceedings and claims, including employment disputes, patent claims, disputes over contract agreements and other commercial disputes. In some cases, claimants seek damages or other relief, such as royalty payments related to patents, which, if granted, could require significant expenditures. Although the outcome of any claim or litigation can never be certain, it is our opinion that the outcome of all contingencies of which we are currently aware will not materially affect our business, operations, financial condition or cash flows. We have committed to invest up to an aggregate of $7.9 million in two private equity funds, and we have contributed $8.4 million as of September 30, 2016, of which $7.7 million has been applied to these commitments.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	15. SUBSEQUENT EVENTS On October 18, 2016, 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 November 03, 2016. The payment date will be November 17, 2016. The quarterly dividend payment will be approximately $4.3 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. During the fourth quarter and as of November 8, 2016, we have repurchased 0.2 million shares of our common stock through open market purchases at an average cost of $17.96 per share. We currently have the authority to purchase an additional 4.4 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)	9 Months Ended
	Sep. 30, 2016
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, 2015, filed on February 24, 2016 with the SEC.
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 (Topic 606) Revenue Recognition with early adoption permitted for reporting periods beginning after December 15, 2016. Subsequently, the FASB issued ASUs in 2016 containing implementation guidance related to ASU 2014-09, including: ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which is intended to improve the operability and understandability of the implementation guidance on principal versus agent considerations; ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , which is intended to clarify two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance; and ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , which contains certain provisions and practical expedients in response to identified implementation issues. In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory Inventory In November 2015, the FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting During the first quarter of 2016, we adopted the following accounting standards, which had no material effect on our financial position, results of operations or cash flows: 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

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Preliminary Allocation of the Purchase Price to the Estimated Fair Value of the Assets Acquired and Liabilities Assumed Subject to Working Capital Adjustments	The preliminary allocation of the purchase price to the estimated fair value of the assets acquired and liabilities assumed at the acquisition date, subject to working capital adjustments, is as follows: (In Thousands) Assets Inventory 3,272 Property, plant and equipment 352 Intangible assets 4,700 Total assets acquired 8,324 Liabilities Accounts payable (1,378 ) Warranty payable (61 ) Accrued wages and benefits (122 ) Deferred income taxes (2,270 ) Total liabilities assumed (3,831 ) Total net assets 4,493 Gain on bargain purchase of a business, net of tax (3,550 ) Total purchase price $ 943
Details of the Acquired Intangible Assets	The details of the acquired intangible assets are as follows: In thousands Value Life (years) Supply agreement $ 1,400 0.8 Customer relationships 1,200 6 Developed technology 800 10 License 500 1.3 Patent 500 7.3 Non-compete 200 2.3 Trade name 100 2 Total $ 4,700
Summary of Actual Revenue and Pre-tax Loss Included in Consolidated Statements of Income	The actual revenue and pre-tax loss included in our Consolidated Statements of Income for the period September 13, 2016 to September 30, 2016 are as follows: September 13 to (In thousands) September 30, 2016 Revenue $ 1,291 Pre-tax loss $ (70 )
Summary of Supplemental Pro Forma Information	The following supplemental pro forma information presents the financial results as if the acquisition had occurred on January 1, 2015. This supplemental pro forma information does not purport to be indicative of what would have occurred had the acquisition been completed on January 1, 2015, nor is it indicative of any future results. Aside from revising the 2015 pre-tax income for the effect of the bargain purchase gain, there were no material, non-recurring adjustments to this pro forma information. Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Pro forma revenue $ 170,498 $ 159,375 $ 478,184 $ 463,916 Pro forma pre-tax income $ 11,778 $ 10,294 $ 35,771 $ 21,826

Pension Benefit Plan (Tables)

Pension Benefit Plan (Tables)	9 Months Ended
	Sep. 30, 2016
Compensation And Retirement Disclosure [Abstract]
Summarization of Components of Net Periodic Pension Cost	The following table summarizes the components of net periodic pension cost for the three and nine months ended September 30, 2016 and 2015: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Service cost $ 305 $ 328 $ 912 $ 992 Interest cost 182 153 542 464 Expected return on plan assets (266 ) (252 ) (796 ) (763 ) Amortization of actuarial losses 44 102 132 307 Net periodic pension cost $ 265 $ 331 $ 790 $ 1,000

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation Expense Related to Stock Options, Restricted Stock Units (RSUs) and Restricted Stock	The following table summarizes the stock-based compensation expense related to stock options, restricted stock units (RSUs) and restricted stock for the three and nine months ended September 30, 2016 and 2015, which was recognized as follows: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Stock-based compensation expense included in cost of sales $ 88 $ 59 $ 282 $ 202 Selling, general and administrative expense 765 812 2,322 2,226 Research and development expense 639 803 1,997 2,360 Stock-based compensation expense included in operating expenses 1,404 1,615 4,319 4,586 Total stock-based compensation expense 1,492 1,674 4,601 4,788 Tax benefit for expense associated with non-qualified options (218 ) (218 ) (643 ) (620 ) Total stock-based compensation expense, net of tax $ 1,274 $ 1,456 $ 3,958 $ 4,168
Summary of Weighted-Average Assumptions and Value of Options Granted	The weighted-average assumptions and value of options granted during the three and nine months ended September 30, 2016 and 2015 are as follows: Three Months Ended Nine Months Ended September 30, September 30, 2016 2015 2016 2015 Expected volatility 34.55 % 34.80 % 34.66 % 36.24 % Risk-free interest rate 1.20 % 1.84 % 1.28 % 1.70 % Expected dividend yield 1.83 % 2.13 % 1.88 % 1.94 % Expected life (in years) 6.21 6.24 6.24 6.32 Weighted-average estimated value $ 5.64 $ 4.89 $ 5.50 $ 5.89
Summary of Stock Options Outstanding	The following table is a summary of our stock options outstanding as of December 31, 2015 and September 30, 2016 and the changes that occurred during the nine months ended September 30, 2016: (In thousands, except per share amounts) Number of Options Weighted Avg. Exercise Price Weighted Avg. Remaining Contractual Life In Years Aggregate Intrinsic Value Options outstanding, December 31, 2015 7,108 $ 21.97 6.42 $ 3,284 Options granted 2 $ 19.19 Options exercised (65 ) $ 16.49 Options forfeited (78 ) $ 17.93 Options expired (142 ) $ 25.49 Options outstanding, September 30, 2016 6,825 $ 22.01 5.69 $ 7,675 Options vested and expected to vest, September 30, 2016 6,729 $ 22.09 5.65 $ 7,414 Options exercisable, September 30, 2016 4,322 $ 24.40 4.19 $ 2,719

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2016
Investments Debt And Equity Securities [Abstract]
Securities and Investments, Recorded at Either Fair Value or Cost	At September 30, 2016, we held the following securities and investments, recorded at either fair value or cost. Amortized Gross Unrealized Carrying (In thousands) Cost Gains Losses Value Deferred compensation plan assets $ 11,656 $ 2,172 $ (20 ) $ 13,808 Corporate bonds 59,900 136 (50 ) 59,986 Municipal fixed-rate bonds 17,589 54 (4 ) 17,639 Asset-backed bonds 22,564 72 (23 ) 22,613 Mortgage/Agency-backed bonds 15,055 24 (43 ) 15,036 U.S. government bonds 28,437 168 - 28,605 Foreign government bonds 6,428 3 (1 ) 6,430 Variable rate demand notes 12,315 - - 12,315 Marketable equity securities 26,975 1,468 (1,076 ) 27,367 Available-for-sale securities held at fair value $ 200,919 $ 4,097 $ (1,217 ) $ 203,799 Restricted investment held at cost 28,900 Other investments held at cost 1,196 Total carrying value of available-for-sale investments $ 233,895 At December 31, 2015, we held the following securities and investments, recorded at either fair value or cost. Amortized Gross Unrealized Carrying (In thousands) Cost Gains Losses Value Deferred compensation plan assets $ 11,325 $ 1,575 $ (66 ) $ 12,834 Corporate bonds 58,328 20 (734 ) 57,614 Municipal fixed-rate bonds 26,414 28 (18 ) 26,424 Asset-backed bonds 19,281 2 (44 ) 19,239 Mortgage/Agency-backed bonds 15,463 1 (91 ) 15,373 U.S. Government bonds 35,646 - (248 ) 35,398 Marketable equity securities 31,643 4,301 (1,693 ) 34,251 Available-for-sale securities held at fair value $ 198,100 $ 5,927 $ (2,894 ) $ 201,133 Restricted investment held at cost 30,000 Other investments held at cost 1,289 Total carrying value of available-for-sale investments $ 232,422
Contractual Maturities of Corporate Bonds, Municipal Fixed-Rate Bonds, Asset-Backed Bonds, Mortgage/Agency-Backed Bonds, U.S. Government Bonds and Foreign Government Bonds	As of September 30, 2016, our corporate bonds, municipal fixed-rate bonds, asset-backed bonds, mortgage/agency-backed bonds, U.S. government bonds, and foreign government bonds had the following contractual maturities: (In thousands) Corporate bonds Municipal fixed-rate bonds Asset- backed bonds Mortgage / Agency- backed bonds U.S. government bonds Foreign government bonds Less than one year $ 22,993 $ 12,156 $ - $ - $ 2,952 $ 5,100 One to two years 24,504 3,186 1,094 1,385 9,096 1,330 Two to three years 9,296 858 8,989 2,004 4,573 - Three to five years 3,193 1,439 9,739 - 11,984 - Five to ten years - - 2,614 1,448 - - More than ten years - - 177 10,199 - - Total $ 59,986 $ 17,639 $ 22,613 $ 15,036 $ 28,605 $ 6,430
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 Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Gross realized gains $ 1,346 $ 2,251 $ 5,226 $ 8,856 Gross realized losses $ (30 ) $ (191 ) $ (1,072 ) $ (426 )
Fair Value Measurements of Cash Equivalents Held in Money Market Funds and Investments	We have categorized our cash equivalents held in money market funds and our investments held at fair value into a three-level fair value hierarchy based on the priority of the inputs to the valuation technique for the cash equivalents and investments as follows: Level 1 - Values based on unadjusted quoted prices for identical assets or liabilities in an active market; Level 2 - Values based on quoted prices in markets that are not active or model inputs that are observable either directly or indirectly; Level 3 - Values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. These inputs include information supplied by investees. Fair Value Measurements at September 30, 2016 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 2,032 $ 2,032 $ - $ - Commercial Paper 3,585 - 3,585 - Cash equivalents 5,617 2,032 3,585 - Available-for-sale securities Deferred compensation plan assets 13,808 13,808 - - Available-for-sale debt securities Corporate bonds 59,986 - 59,986 - Municipal fixed-rate bonds 17,639 - 17,639 - Asset-backed bonds 22,613 - 22,613 - Mortgage/Agency-backed bonds 15,036 - 15,036 - U.S. government bonds 28,605 28,605 - - Foreign government bonds 6,430 - 6,430 - Variable rate demand notes 12,315 - 12,315 - Available-for-sale marketable equity securities Marketable equity securities – technology industry 3,693 3,693 - - Marketable equity securities – other 23,674 23,674 - - Available-for-sale securities 203,799 69,780 134,019 - Total $ 209,416 $ 71,812 $ 137,604 $ - Fair Value Measurements at December 31, 2015 Using (In thousands) Fair Value Quoted Prices in Active Market for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Cash equivalents Money market funds $ 1,271 $ 1,271 $ - $ - Commercial Paper 11,696 - 11,696 - Cash equivalents 12,967 1,271 11,696 - Available-for-sale securities Deferred compensation plan assets 12,834 12,834 - - Available-for-sale debt securities Corporate bonds 57,614 - 57,614 - Municipal fixed-rate bonds 26,424 - 26,424 - Asset-backed bonds 19,239 - 19,239 - Mortgage/Agency-backed bonds 15,373 - 15,373 - U.S. government bonds 35,398 35,398 - - Available-for-sale marketable equity securities Marketable equity securities – technology industry 5,384 5,384 - - Marketable equity securities – other 28,867 28,867 - - Available-for-sale securities 201,133 82,483 118,650 - Total $ 214,100 $ 83,754 $ 130,346 $ -

Derivative Instruments and He27

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Schedule of Change in Fair Values of Derivative Instruments Recorded in Consolidated Statements of Income	The change in the fair values of our derivative instruments recorded in the Consolidated Statements of Income during the three and nine months ended September 30, 2016 and 2015 were as follows: Three Months Ended Nine Months Ended Income Statement September 30, September 30, (In thousands) Location 2016 2015 2016 2015 Derivatives Not Designated as Hedging Instruments: Foreign exchange contracts Other income (expense) $ (37 ) $ 30 $ 153 $ 208

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Components of Inventory	At September 30, 2016 and December 31, 2015, inventory consisted of the following: September 30, December 31, (In thousands) 2016 2015 Raw materials $ 37,879 $ 34,223 Work in process 3,044 2,893 Finished goods 55,111 54,417 Total $ 96,034 $ 91,533

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	The following table presents our intangible assets as of September 30, 2016 and December 31, 2015: (In thousands) September 30, 2016 December 31, 2015 Gross Value Accumulated Amortization Net Value Gross Value Accumulated Amortization Net Value Customer relationships $ 7,178 $ (3,147 ) 4,031 $ 5,828 $ (2,627 ) $ 3,201 Developed technology 6,609 (4,995 ) 1,614 5,720 (4,329 ) 1,391 Intellectual property 2,340 (2,096 ) 244 2,340 (1,854 ) 486 Supply agreement 1,400 (78 ) 1,322 - - - License 500 (16 ) 484 - - - Patent 500 (3 ) 497 - - - Trade names 370 (272 ) 98 270 (265 ) 5 Non-compete 200 (4 ) 196 11 (11 ) - Total $ 19,097 $ (10,611 ) $ 8,486 $ 14,169 $ (9,086 ) $ 5,083
Estimated Future Amortization Expense Related to Intangible Assets	As of September 30, 2016, the estimated future amortization expense of our intangible assets is as follows: (In thousands) Amount Remainder of 2016 $ 1,058 2017 2,901 2018 1,189 2019 675 2020 640 Thereafter 2,023 Total $ 8,486

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Summary of Changes in Stockholders' Equity	A summary of the changes in stockholders’ equity for the nine months ended September 30, 2016 is as follows: (In thousands) Stockholders’ Equity Balance, December 31, 2015 $ 480,160 Net income 27,657 Dividend payments (13,230 ) Dividends accrued for unvested restricted stock units (30 ) Net unrealized losses on available-for-sale securities (net of tax) (162 ) Defined benefit plan adjustments 103 Foreign currency translation adjustment 1,202 Proceeds from stock option exercises 1,076 Purchase of treasury stock (22,917 ) Income tax effect of stock compensation arrangements (263 ) Stock-based compensation expense 4,601 Balance, September 30, 2016 $ 478,197
Cash Dividends	During the nine months ended September 30, 2016, we paid cash dividends as follows (in thousands except per share amounts): Record Date Payment Date Per Share Amount Total Dividend Paid February 4, 2016 February 18, 2016 $ 0.09 $ 4,453 April 28, 2016 May 12, 2016 $ 0.09 $ 4,407 July 28, 2016 August 11, 2016 $ 0.09 $ 4,370
Changes in Accumulated Other Comprehensive Income, Net of Tax by Component	The following tables present changes in accumulated other comprehensive income, net of tax, by component for the three months ended September 30, 2016 and 2015: Three Months Ended September 30, 2016 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 1,512 $ (3,828 ) $ (6,379 ) $ (8,695 ) Other comprehensive income (loss) before reclassifications 1,028 - 575 1,603 Amounts reclassified from accumulated other comprehensive income (770 ) 36 - (734 ) Net current period other comprehensive income (loss) 258 36 575 869 Ending balance $ 1,770 $ (3,792 ) $ (5,804 ) $ (7,826 ) Three Months Ended September 30, 2015 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 6,678 $ (5,617 ) $ (5,728 ) $ (4,667 ) Other comprehensive income (loss) before reclassifications (3,034 ) - (1,351 ) (4,385 ) Amounts reclassified from accumulated other comprehensive income (1,257 ) 71 - (1,186 ) Net current period other comprehensive income (loss) (4,291 ) 71 (1,351 ) (5,571 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 ) The following tables present changes in accumulated other comprehensive income, net of tax, by component for the nine months ended September 30, 2016 and 2015: Nine Months Ended September 30, 2016 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 1,932 $ (3,895 ) $ (7,006 ) $ (8,969 ) Other comprehensive income (loss) before reclassifications 2,267 - 1,202 3,469 Amounts reclassified from accumulated other comprehensive income (2,429 ) 103 - (2,326 ) Net current period other comprehensive income (loss) (162 ) 103 1,202 1,143 Ending balance $ 1,770 $ (3,792 ) $ (5,804 ) $ (7,826 ) Nine Months Ended September 30, 2015 (In thousands) Unrealized Gains (Losses) on Available- for-Sale Securities Defined Benefit Plan Adjustments Foreign Currency Adjustments Total Beginning balance $ 8,964 $ (5,757 ) $ (3,282 ) $ (75 ) Other comprehensive income (loss) before reclassifications (1,497 ) - (3,797 ) (5,294 ) Amounts reclassified from accumulated other comprehensive income (5,080 ) 211 - (4,869 ) Net current period other comprehensive income (loss) (6,577 ) 211 (3,797 ) (10,163 ) Ending balance $ 2,387 $ (5,546 ) $ (7,079 ) $ (10,238 )
Reclassifications Out of Accumulated Other Comprehensive Income	The following tables present the details of reclassifications out of accumulated other comprehensive income for the three months ended September 30, 2016 and 2015: (In thousands) Three Months Ended September 30, 2016 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 1,268 Net realized investment gain Impairment expense (6 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (51 ) (1) Total reclassifications for the period, before tax 1,211 Tax (expense) benefit (477 ) Total reclassifications for the period, net of tax $ 734 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements. (In thousands) Three Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 2,098 Net realized investment gain Impairment expense (37 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (103 ) (1) Total reclassifications for the period, before tax 1,958 Tax (expense) benefit (772 ) Total reclassifications for the period, net of tax $ 1,186 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements. The following tables present the details of reclassifications out of accumulated other comprehensive income for the nine months ended September 30, 2016 and 2015: (In thousands) Nine Months Ended September 30, 2016 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 4,383 Net realized investment gain Impairment expense (401 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (149 ) (1) Total reclassifications for the period, before tax 3,833 Tax (expense) benefit (1,507 ) Total reclassifications for the period, net of tax $ 2,326 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements. (In thousands) Nine Months Ended September 30, 2015 Details about Accumulated Other Comprehensive Income Components Amount Reclassified from Accumulated Other Comprehensive Income Affected Line Item in the Statement Where Net Income Is Presented Unrealized gains (losses) on available-for- sale securities: Net realized gain on sales of securities $ 8,438 Net realized investment gain Impairment expense (110 ) Net realized investment gain Defined benefit plan adjustments – actuarial losses (306 ) (1) Total reclassifications for the period, before tax 8,022 Tax (expense) benefit (3,153 ) Total reclassifications for the period, net of tax $ 4,869 (1) Included in the computation of net periodic pension cost. See Note 4 of Notes to Consolidated Financial Statements.
Other Comprehensive Income	The following table presents the tax effects related to the change in each component of other comprehensive income for the three months ended September 30, 2016 and 2015: Three Months Ended Three Months Ended September 30, 2016 September 30, 2015 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Unrealized gains (losses) on available-for-sale securities $ 1,685 $ (657 ) $ 1,028 $ (4,974 ) $ 1,940 $ (3,034 ) Reclassification adjustment for amounts related to available-for-sale investments included in net income (1,262 ) 492 (770 ) (2,061 ) 804 (1,257 ) Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income 51 (15 ) 36 103 (32 ) 71 Foreign currency translation adjustment 575 - 575 (1,351 ) - (1,351 ) Total Other Comprehensive Income (Loss) $ 1,049 $ (180 ) $ 869 $ (8,283 ) $ 2,712 $ (5,571 ) The following table presents the tax effects related to the change in each component of other comprehensive income for the nine months ended September 30, 2016 and 2015: Nine Months Ended Nine Months Ended September 30, 2016 September 30, 2015 (In thousands) Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Before-Tax Amount Tax (Expense) Benefit Net-of-Tax Amount Unrealized gains (losses) on available-for-sale securities $ 3,716 $ (1,449 ) $ 2,267 $ (2,454 ) $ 957 $ (1,497 ) Reclassification adjustment for amounts related to available-for-sale investments included in net income (3,982 ) 1,553 (2,429 ) (8,328 ) 3,248 (5,080 ) Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income 149 (46 ) 103 306 (95 ) 211 Foreign currency translation adjustment 1,202 - 1,202 (3,797 ) - (3,797 ) Total Other Comprehensive Income (Loss) $ 1,085 $ 58 $ 1,143 $ (14,273 ) $ 4,110 $ (10,163 )

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Summary of Calculation of Basic and Diluted Earnings Per Share	A summary of the calculation of basic and diluted earnings per share for the three and nine months ended September 30, 2016 and 2015 is as follows: Three Months Ended Nine Months Ended September 30, September 30, (In thousands, except per share amounts) 2016 2015 2016 2015 Numerator Net income $ 12,415 $ 7,067 $ 27,657 $ 12,928 Denominator Weighted average number of shares – basic 48,470 49,862 48,839 51,682 Effect of dilutive securities Stock options 137 29 137 94 Restricted stock and restricted stock units 71 36 60 16 Weighted average number of shares – diluted 48,678 49,927 49,036 51,792 Net income per share – basic $ 0.26 $ 0.14 $ 0.57 $ 0.25 Net income per share – diluted $ 0.26 $ 0.14 $ 0.56 $ 0.25

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Sales and Gross Profit of Reportable Segments	The following table presents information about the reported sales and gross profit of our reportable segments for the three and nine months ended September 30, 2016 and 2015. We do not produce asset information by reportable segment; therefore, it is not reported. Three Months Ended September 30, 2016 September 30, 2015 (In thousands) Sales Gross Profit Sales Gross Profit Network Solutions $ 136,277 $ 65,289 $ 138,120 $ 62,151 Services & Support 32,613 10,519 19,958 8,498 Total $ 168,890 $ 75,808 $ 158,078 $ 70,649 Nine Months Ended September 30, 2016 September 30, 2015 (In thousands) Sales Gross Profit Sales Gross Profit Network Solutions $ 398,709 $ 195,804 $ 411,723 $ 179,984 Services & Support 75,086 24,753 49,328 24,474 Total $ 473,795 $ 220,557 $ 461,051 $ 204,458
Sales Information by Category	The table below presents sales information by category for the three and nine months ended September 30, 2016 and 2015: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Access & Aggregation $ 120,618 $ 103,431 $ 316,705 $ 309,014 Customer Devices 32,984 35,545 106,213 97,291 Traditional & Other Products 15,288 19,102 50,877 54,746 Total $ 168,890 $ 158,078 $ 473,795 $ 461,051

Liability for Warranty Returns

Liability for Warranty Returns (Tables)	9 Months Ended
	Sep. 30, 2016
Product Warranties Disclosures [Abstract]
Summary of Warranty Expense and Write-Off Activity	A summary of warranty expense and write-off activity for the three and nine months ended September 30, 2016 and 2015 is as follows: Three Months Ended Nine Months Ended September 30, September 30, (In thousands) 2016 2015 2016 2015 Balance at beginning of period $ 8,935 $ 8,933 $ 8,739 $ 8,415 Plus: Amounts charged to cost and expenses 4,012 777 6,341 1,905 Less: Deductions (4,195 ) (994 ) (6,328 ) (1,604 ) Balance at end of period $ 8,752 $ 8,716 $ 8,752 $ 8,716

Business Combinations - Additio

Business Combinations - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 13, 2016	Sep. 30, 2016	Sep. 30, 2016
Business Acquisition [Line Items]
Cash consideration			$ 943
Bargain purchase gain net of income taxes		$ 3,550	$ 3,550
CommScope, Inc. Subsidiaries Fiber Access Products, Technologies and Service Relationships [Member]
Business Acquisition [Line Items]
Date of acquisition			Sep. 13, 2016
Business acquisition, description			On September 13, 2016, we acquired key fiber access products, technologies and service relationships from subsidiaries of CommScope, Inc. for $0.9 million in cash. This acquisition will enhance our solutions for the cable MSO industry and will provide cable operators with the scalable solutions, services and support they require to compete in the multi-gigabit service delivery market.
Cash consideration	$ 943
Bargain purchase gain net of income taxes	$ 3,550
Acquisition and integration related expenses and amortization of acquired intangibles		$ 200

Business Combinations - Prelimi

Business Combinations - Preliminary Allocation of the Purchase Price to the Estimated Fair Value of the Assets Acquired and Liabilities Assumed Subject to Working Capital Adjustments (Detail) - USD ($) $ in Thousands	Sep. 13, 2016	Sep. 30, 2016	Sep. 30, 2016
Liabilities
Gain on bargain purchase of a business, net of tax		$ (3,550)	$ (3,550)
Total purchase price			$ 943
CommScope, Inc. Subsidiaries Fiber Access Products, Technologies and Service Relationships [Member]
Assets
Inventory	$ 3,272
Property, plant and equipment	352
Intangible assets	4,700
Total assets acquired	8,324
Liabilities
Accounts payable	(1,378)
Warranty payable	(61)
Accrued wages and benefits	(122)
Deferred income taxes	(2,270)
Total liabilities assumed	(3,831)
Total net assets	4,493
Gain on bargain purchase of a business, net of tax	(3,550)
Total purchase price	$ 943

Business Combinations - Details

Business Combinations - Details of the Acquired Intangible Assets (Detail) - CommScope, Inc. Subsidiaries Fiber Access Products, Technologies and Service Relationships [Member] $ in Thousands	Sep. 13, 2016USD ($)
Business Acquisition [Line Items]
Total, Value	$ 4,700
Supply Agreement [Member]
Business Acquisition [Line Items]
Total, Value	$ 1,400
Life (years)	9 months 18 days
Customer Relationships [Member]
Business Acquisition [Line Items]
Total, Value	$ 1,200
Life (years)	6 years
Developed Technology [Member]
Business Acquisition [Line Items]
Total, Value	$ 800
Life (years)	10 years
License [Member]
Business Acquisition [Line Items]
Total, Value	$ 500
Life (years)	1 year 3 months 18 days
Patent [Member]
Business Acquisition [Line Items]
Total, Value	$ 500
Life (years)	7 years 3 months 18 days
Non-compete [Member]
Business Acquisition [Line Items]
Total, Value	$ 200
Life (years)	2 years 3 months 18 days
Trade Name [Member]
Business Acquisition [Line Items]
Total, Value	$ 100
Life (years)	2 years

Business Combinations - Summary

Business Combinations - Summary of Actual Revenue and Pre-tax Loss Included in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition [Line Items]
Revenue		$ 168,890	$ 158,078	$ 473,795	$ 461,051
Pre-tax loss		$ 15,517	$ 10,872	$ 40,051	$ 20,493
CommScope, Inc. Subsidiaries Fiber Access Products, Technologies and Service Relationships [Member]
Business Acquisition [Line Items]
Revenue	$ 1,291
Pre-tax loss	$ (70)

Business Combinations - Summa38

Business Combinations - Summary of Supplemental Pro Forma Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Combinations [Abstract]
Pro forma revenue	$ 170,498	$ 159,375	$ 478,184	$ 463,916
Pro forma pre-tax income	$ 11,778	$ 10,294	$ 35,771	$ 21,826

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Effective tax rate	34.00%	36.90%

Pension Benefit Plan - Summariz

Pension Benefit Plan - Summarization of Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Compensation And Retirement Disclosure [Abstract]
Service cost	$ 305	$ 328	$ 912	$ 992
Interest cost	182	153	542	464
Expected return on plan assets	(266)	(252)	(796)	(763)
Amortization of actuarial losses	44	102	132	307
Net periodic pension cost	$ 265	$ 331	$ 790	$ 1,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense Related to Stock Options, Restricted Stock Units (RSUs) and Restricted Stock (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,492	$ 1,674	$ 4,601	$ 4,788
Tax benefit for expense associated with non-qualified options	(218)	(218)	(643)	(620)
Total stock-based compensation expense, net of tax	1,274	1,456	3,958	4,168
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	88	59	282	202
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	765	812	2,322	2,226
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	639	803	1,997	2,360
Operating Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,404	$ 1,615	$ 4,319	$ 4,586

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Weighted-Average Assumptions and Value of Options Granted (Detail) - Stock Options [Member] - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	34.55%	34.80%	34.66%	36.24%
Risk-free interest rate	1.20%	1.84%	1.28%	1.70%
Expected dividend yield	1.83%	2.13%	1.88%	1.94%
Expected life (in years)	6 years 2 months 16 days	6 years 2 months 27 days	6 years 2 months 27 days	6 years 3 months 26 days
Weighted-average estimated value	$ 5.64	$ 4.89	$ 5.50	$ 5.89

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated forfeitures for stock options			3.70%
Total pre-tax intrinsic value of options exercised	$ 0.1		$ 0.2
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 vesting in period	0	0	0	0
Number of RSUs and restricted stock forfeitures in period				12,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs and restricted stock grants in period	2,000		4,000
Number of RSUs and restricted stock vesting in period		2,000		2,000
Recognition period of non-vested compensation cost			2 years 2 months 12 days
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%
Compensation cost related to non-vested stock options not yet recognized	$ 9.9		$ 9.9

Stock-Based Compensation - Su44

Stock-Based Compensation - Summary of Stock Options Outstanding (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Options outstanding, Beginning Balance	7,108
Number of Options, Options granted	2
Number of Options, Options exercised	(65)
Number of Options, Options forfeited	(78)
Number of Options, Options expired	(142)
Number of Options, Options outstanding, Ending Balance	6,825	7,108
Number of Options, Options vested and expected to vest	6,729
Number of Options, Options exercisable	4,322
Weighted Average Exercise Price, Options outstanding, Beginning Balance	$ 21.97
Weighted Average Exercise Price, Options granted	19.19
Weighted Average Exercise Price, Options exercised	16.49
Weighted Average Exercise Price, Options forfeited	17.93
Weighted Average Exercise Price, Options expired	25.49
Weighted Average Exercise Price, Options outstanding, Ending Balance	22.01	$ 21.97
Weighted Average Exercise Price, Options vested and expected to vest	22.09
Weighted Average Exercise Price, Options exercisable	$ 24.40
Weighted Average Remaining Contractual Life In Years, Options outstanding	5 years 8 months 9 days	6 years 5 months 1 day
Weighted Average Remaining Contractual Life In Years, Options vested and expected to vest	5 years 7 months 24 days
Weighted Average Remaining Contractual Life In Years, Options exercisable	4 years 2 months 9 days
Aggregate Intrinsic Value, Options outstanding, Beginning Balance	$ 3,284
Aggregate Intrinsic Value, Options outstanding, Ending Balance	7,675	$ 3,284
Aggregate Intrinsic Value, Options vested and expected to vest	7,414
Aggregate Intrinsic Value, Options exercisable	$ 2,719

Investments - Securities and In

Investments - Securities and Investments, Recorded at Either Fair Value or Cost (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 200,919	$ 198,100
Gross Unrealized Gains	4,097	5,927
Gross Unrealized Losses	(1,217)	(2,894)
Available-for-sale-securities, Carrying Value	203,799	201,133
Restricted investment held at cost	28,900	30,000
Other investments held at cost	1,196	1,289
Total carrying value of available-for-sale investments	233,895	232,422
Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,656	11,325
Gross Unrealized Gains	2,172	1,575
Gross Unrealized Losses	(20)	(66)
Available-for-sale-securities, Carrying Value	13,808	12,834
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	59,900	58,328
Gross Unrealized Gains	136	20
Gross Unrealized Losses	(50)	(734)
Available-for-sale-securities, Carrying Value	59,986	57,614
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,589	26,414
Gross Unrealized Gains	54	28
Gross Unrealized Losses	(4)	(18)
Available-for-sale-securities, Carrying Value	17,639	26,424
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,564	19,281
Gross Unrealized Gains	72	2
Gross Unrealized Losses	(23)	(44)
Available-for-sale-securities, Carrying Value	22,613	19,239
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,055	15,463
Gross Unrealized Gains	24	1
Gross Unrealized Losses	(43)	(91)
Available-for-sale-securities, Carrying Value	15,036	15,373
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,437	35,646
Gross Unrealized Gains	168
Gross Unrealized Losses		(248)
Available-for-sale-securities, Carrying Value	28,605	35,398
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,428
Gross Unrealized Gains	3
Gross Unrealized Losses	(1)
Available-for-sale-securities, Carrying Value	6,430
Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,315
Available-for-sale-securities, Carrying Value	12,315
Marketable Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	26,975	31,643
Gross Unrealized Gains	1,468	4,301
Gross Unrealized Losses	(1,076)	(1,693)
Available-for-sale-securities, Carrying Value	$ 27,367	$ 34,251

Investments - Contractual Matur

Investments - Contractual Maturities of Corporate Bonds, Municipal Fixed-Rate Bonds, Asset-Backed Bonds, Mortgage/Agency-Backed Bonds, U.S. Government Bonds and Foreign Government Bonds (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale-securities, Fair Value/Carrying Value	$ 203,799	$ 201,133
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	22,993
One to two years	24,504
Two to three years	9,296
Three to five years	3,193
Available-for-sale-securities, Fair Value/Carrying Value	59,986	57,614
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	12,156
One to two years	3,186
Two to three years	858
Three to five years	1,439
Available-for-sale-securities, Fair Value/Carrying Value	17,639	26,424
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
One to two years	1,094
Two to three years	8,989
Three to five years	9,739
Five to ten years	2,614
More than ten years	177
Available-for-sale-securities, Fair Value/Carrying Value	22,613	19,239
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
One to two years	1,385
Two to three years	2,004
Five to ten years	1,448
More than ten years	10,199
Available-for-sale-securities, Fair Value/Carrying Value	15,036	15,373
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	2,952
One to two years	9,096
Two to three years	4,573
Three to five years	11,984
Available-for-sale-securities, Fair Value/Carrying Value	28,605	$ 35,398
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than one year	5,100
One to two years	1,330
Available-for-sale-securities, Fair Value/Carrying Value	$ 6,430

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule of Investments [Line Items]
Restricted certificate of deposit held	$ 28,900	$ 30,000
Identification of potential other-than-temporary impairments	25.00%
Alabama State Industrial Development Authority [Member]
Schedule of Investments [Line Items]
Maturity date of bond	Jan. 1, 2020
Percentage of interest on bond	2.00%
Alabama State Industrial Development Authority [Member] | Taxable Revenue Bond [Member]
Schedule of Investments [Line Items]
Collateral deposit against outstanding principal amount	$ 28,900	$ 28,900
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	$ 29,300
Investment [Member] | Issuer Concentration [Member] | Market Value of Total Investment Portfolio [Member]
Schedule of Investments [Line Items]
Investment concentration risk percentage	5.00%

Investments - Gross Realized Ga

Investments - Gross Realized Gains and Losses on Sale of Securities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Investments Debt And Equity Securities [Abstract]
Gross realized gains	$ 1,346	$ 2,251	$ 5,226	$ 8,856
Gross realized losses	$ (30)	$ (191)	$ (1,072)	$ (426)

Investments - Fair Value Measur

Investments - Fair Value Measurements of Cash Equivalents Held in Money Market Funds and Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 203,799	$ 201,133
Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	13,808	12,834
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	59,986	57,614
Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	17,639	26,424
Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	22,613	19,239
Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	15,036	15,373
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	28,605	35,398
Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	6,430
Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	12,315
Fair Value, Measurements [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	5,617	12,967
Available-for-sale securities	203,799	201,133
Total	209,416	214,100
Fair Value, Measurements [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	2,032	1,271
Available-for-sale securities	69,780	82,483
Total	71,812	83,754
Fair Value, Measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	3,585	11,696
Available-for-sale securities	134,019	118,650
Total	137,604	130,346
Fair Value, Measurements [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	2,032	1,271
Fair Value, Measurements [Member] | Money Market Funds [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	2,032	1,271
Fair Value, Measurements [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	3,585	11,696
Fair Value, Measurements [Member] | Commercial Paper [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash equivalents	3,585	11,696
Fair Value, Measurements [Member] | Deferred Compensation Plan Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	13,808	12,834
Fair Value, Measurements [Member] | Deferred Compensation Plan Assets [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	13,808	12,834
Fair Value, Measurements [Member] | Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	59,986	57,614
Fair Value, Measurements [Member] | Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	59,986	57,614
Fair Value, Measurements [Member] | Municipal Fixed-Rate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	17,639	26,424
Fair Value, Measurements [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	17,639	26,424
Fair Value, Measurements [Member] | Asset-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	22,613	19,239
Fair Value, Measurements [Member] | Asset-Backed Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	22,613	19,239
Fair Value, Measurements [Member] | Mortgage/Agency-Backed Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	15,036	15,373
Fair Value, Measurements [Member] | Mortgage/Agency-Backed Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	15,036	15,373
Fair Value, Measurements [Member] | U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	28,605	35,398
Fair Value, Measurements [Member] | U.S. Government Bonds [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	28,605	35,398
Fair Value, Measurements [Member] | Foreign Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	6,430
Fair Value, Measurements [Member] | Foreign Government Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	6,430
Fair Value, Measurements [Member] | Variable Rate Demand Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	12,315
Fair Value, Measurements [Member] | Variable Rate Demand Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	12,315
Fair Value, Measurements [Member] | Marketable Equity Securities - Technology Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	3,693	5,384
Fair Value, Measurements [Member] | Marketable Equity Securities - Technology Industry [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	3,693	5,384
Fair Value, Measurements [Member] | Marketable Equity Securities - Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	23,674	28,867
Fair Value, Measurements [Member] | Marketable Equity Securities - Other [Member] | Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities	$ 23,674	$ 28,867

Derivative Instruments and He50

Derivative Instruments and Hedging Activities - Additional Information (Detail)	Sep. 30, 2016USD ($)	Sep. 30, 2016EUR (€)	Dec. 31, 2015USD ($)	Dec. 31, 2015EUR (€)
Forward Contracts [Member]
Derivative [Line Items]
Derivative, notional amount	$ 0	€ 0	$ 0	€ 0

Derivative Instruments and He51

Derivative Instruments and Hedging Activities - Schedule of Change in Fair Values of Derivative Instruments Recorded in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Foreign Exchange Contracts [Member] | Other Income (Expense) [Member]
Derivatives Not Designated as Hedging Instruments:
Derivative instrument, gain or loss	$ (37)	$ 30	$ 153	$ 208

Inventory - Components of Inven

Inventory - Components of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw materials	$ 37,879	$ 34,223
Work in process	3,044	2,893
Finished goods	55,111	54,417
Total	$ 96,034	$ 91,533

Inventory - Additional Informat

Inventory - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Raw Materials [Member]
Inventory [Line Items]
Inventory valuation reserves	$ 18.3	$ 17.5
Finished Goods [Member]
Inventory [Line Items]
Inventory valuation reserves	$ 10.1	$ 9.2

Goodwill and Intangible Asset54

Goodwill and Intangible Assets - Additional Information (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)Segment	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Goodwill [Line Items]
Goodwill, relates to acquisition			$ 3,500,000		$ 3,500,000
Number of reportable segments | Segment			2
Impairment losses			$ 0
Amortization expense	$ 500,000	$ 500,000	1,400,000	$ 1,500,000
Network Solutions [Member]
Goodwill [Line Items]
Goodwill, relates to acquisition			3,100,000
Services & Support [Member]
Goodwill [Line Items]
Goodwill, relates to acquisition			$ 400,000

Goodwill and Intangible Asset55

Goodwill and Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Goodwill [Line Items]
Gross Value	$ 19,097	$ 14,169
Accumulated Amortization	(10,611)	(9,086)
Net Value	8,486	5,083
Customer Relationships [Member]
Goodwill [Line Items]
Gross Value	7,178	5,828
Accumulated Amortization	(3,147)	(2,627)
Net Value	4,031	3,201
Developed Technology [Member]
Goodwill [Line Items]
Gross Value	6,609	5,720
Accumulated Amortization	(4,995)	(4,329)
Net Value	1,614	1,391
Intellectual Property [Member]
Goodwill [Line Items]
Gross Value	2,340	2,340
Accumulated Amortization	(2,096)	(1,854)
Net Value	244	486
Supply Agreement [Member]
Goodwill [Line Items]
Gross Value	1,400
Accumulated Amortization	(78)
Net Value	1,322
License [Member]
Goodwill [Line Items]
Gross Value	500
Accumulated Amortization	(16)
Net Value	484
Trade Names [Member]
Goodwill [Line Items]
Gross Value	370	270
Accumulated Amortization	(272)	(265)
Net Value	98	5
Patent [Member]
Goodwill [Line Items]
Gross Value	500
Accumulated Amortization	(3)
Net Value	497
Non-compete [Member]
Goodwill [Line Items]
Gross Value	200	11
Accumulated Amortization	(4)	$ (11)
Net Value	$ 196

Goodwill and Intangible Asset56

Goodwill and Intangible Assets - Estimated Future Amortization Expense Related to Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Remainder of 2016	$ 1,058
2,017	2,901
2,018	1,189
2,019	675
2,020	640
Thereafter	2,023
Net Value	$ 8,486	$ 5,083

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Changes in Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Equity [Abstract]
Beginning Balance			$ 480,160
Net income	$ 12,415	$ 7,067	27,657	$ 12,928
Dividend payments			(13,230)
Dividends accrued for unvested restricted stock units			(30)
Net unrealized losses on available-for-sale securities (net of tax)	258	(4,291)	(162)	(6,577)
Defined benefit plan adjustments	36	71	103	211
Foreign currency translation adjustment	575	$ (1,351)	1,202	(3,797)
Proceeds from stock option exercises			1,076	$ 907
Purchase of treasury stock			(22,917)
Income tax effect of stock compensation arrangements			(263)
Stock-based compensation expense			4,601
Ending Balance	$ 478,197		$ 478,197

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Equity [Abstract]
Maximum shares authorized for repurchase, prior and new announcements and total after new announcement	50,000,000
Stock repurchased, shares	1,200,000
Shares repurchased, average price per share	$ 18.34
Additional shares authorized for purchase	4,600,000
Number of Options, exercised	65,000
Exercise price of stock options, lower range limit	$ 15.29
Exercise price of stock options, upper range limit	$ 18.97
Proceeds from stock option exercises	$ 1,076	$ 907

Stockholders' Equity - Cash Div

Stockholders' Equity - Cash Dividends (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Dividends Payable [Line Items]
Record Date			Nov. 3, 2016
Payment Date			Nov. 17, 2016
Per Share Amount	$ 0.09	$ 0.09	$ 0.27	$ 0.27
Total Dividend Paid			$ 13,230	$ 13,989
Cash Dividends Paid in February [Member]
Dividends Payable [Line Items]
Record Date			Feb. 4, 2016
Payment Date			Feb. 18, 2016
Per Share Amount			$ 0.09
Total Dividend Paid			$ 4,453
Cash Dividends Paid in May [Member]
Dividends Payable [Line Items]
Record Date			Apr. 28, 2016
Payment Date			May 12, 2016
Per Share Amount			$ 0.09
Total Dividend Paid			$ 4,407
Cash Dividends Paid in August [Member]
Dividends Payable [Line Items]
Record Date			Jul. 28, 2016
Payment Date			Aug. 11, 2016
Per Share Amount			$ 0.09
Total Dividend Paid			$ 4,370

Stockholders' Equity - Changes

Stockholders' Equity - Changes in Accumulated Other Comprehensive Income, Net of Tax by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (8,695)	$ (4,667)	$ (8,969)	$ (75)
Other comprehensive income (loss) before reclassifications	1,603	(4,385)	3,469	(5,294)
Amounts reclassified from accumulated other comprehensive income	(734)	(1,186)	(2,326)	(4,869)
Other Comprehensive Income (Loss), net of tax	869	(5,571)	1,143	(10,163)
Ending balance	(7,826)	(10,238)	(7,826)	(10,238)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	1,512	6,678	1,932	8,964
Other comprehensive income (loss) before reclassifications	1,028	(3,034)	2,267	(1,497)
Amounts reclassified from accumulated other comprehensive income	(770)	(1,257)	(2,429)	(5,080)
Other Comprehensive Income (Loss), net of tax	258	(4,291)	(162)	(6,577)
Ending balance	1,770	2,387	1,770	2,387
Defined Benefit Plan Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(3,828)	(5,617)	(3,895)	(5,757)
Amounts reclassified from accumulated other comprehensive income	36	71	103	211
Other Comprehensive Income (Loss), net of tax	36	71	103	211
Ending balance	(3,792)	(5,546)	(3,792)	(5,546)
Foreign Currency Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(6,379)	(5,728)	(7,006)	(3,282)
Other comprehensive income (loss) before reclassifications	575	(1,351)	1,202	(3,797)
Other Comprehensive Income (Loss), net of tax	575	(1,351)	1,202	(3,797)
Ending balance	$ (5,804)	$ (7,079)	$ (5,804)	$ (7,079)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Income before provision for income taxes	$ 15,517	$ 10,872	$ 40,051	$ 20,493
Tax (expense) benefit	(3,102)	(3,805)	(12,394)	(7,565)
Total reclassifications for the period, net of tax	12,415	7,067	27,657	12,928
Reclassification Out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit plan adjustments – actuarial losses	(51)	(103)	(149)	(306)
Income before provision for income taxes	1,211	1,958	3,833	8,022
Tax (expense) benefit	(477)	(772)	(1,507)	(3,153)
Total reclassifications for the period, net of tax	734	1,186	2,326	4,869
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	1,268	2,098	4,383	8,438
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	$ (6)	$ (37)	$ (401)	$ (110)

Stockholders' Equity - Other Co

Stockholders' Equity - Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Equity [Abstract]
Unrealized gains (losses) on available-for-sale securities, Before-Tax Amount	$ 1,685	$ (4,974)	$ 3,716	$ (2,454)
Reclassification adjustment for amounts related to available-for-sale investments included in net income, Before-Tax Amount	(1,262)	(2,061)	(3,982)	(8,328)
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income, Before-Tax Amount	51	103	149	306
Foreign currency translation adjustment, Before-Tax Amount	575	(1,351)	1,202	(3,797)
Total Other Comprehensive Income (Loss), Before-Tax Amount	1,049	(8,283)	1,085	(14,273)
Unrealized gains (losses) on available-for-sale securities, Tax (Expense) Benefit	(657)	1,940	(1,449)	957
Reclassification adjustment for amounts related to available-for-sale investments included in net income, Tax (Expense) Benefit	492	804	1,553	3,248
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income, Tax (Expense) Benefit	(15)	(32)	(46)	(95)
Total Other Comprehensive Income (Loss), Tax (Expense) Benefit	(180)	2,712	58	4,110
Unrealized gains (losses) on available-for-sale securities, Net-of-Tax Amount	1,028	(3,034)	2,267	(1,497)
Reclassification adjustment for amounts related to available-for-sale investments included in net income, Net-of-Tax Amount	(770)	(1,257)	(2,429)	(5,080)
Reclassification adjustment for amounts related to defined benefit plan adjustments included in net income, Net-of-Tax Amount	36	71	103	211
Foreign currency translation adjustment, Net-of-Tax Amount	575	(1,351)	1,202	(3,797)
Other Comprehensive Income (Loss), net of tax	$ 869	$ (5,571)	$ 1,143	$ (10,163)

Earnings Per Share - Summary of

Earnings Per Share - Summary of Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator
Net income	$ 12,415	$ 7,067	$ 27,657	$ 12,928
Denominator
Weighted average number of shares – basic	48,470	49,862	48,839	51,682
Effect of dilutive securities
Stock options	137	29	137	94
Restricted stock and restricted stock units	71	36	60	16
Weighted average number of shares – diluted	48,678	49,927	49,036	51,792
Net income per share – basic	$ 0.26	$ 0.14	$ 0.57	$ 0.25
Net income per share – diluted	$ 0.26	$ 0.14	$ 0.56	$ 0.25

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Anti-dilutive options, Total	5.6	6	5.7	6.1

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016SegmentCategory
Segment Reporting [Abstract]
Number of reportable segments | Segment	2
Number of categories | Category	3

Segment Information - Sales and

Segment Information - Sales and Gross Profit of Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Sales	$ 168,890	$ 158,078	$ 473,795	$ 461,051
Gross Profit	75,808	70,649	220,557	204,458
Network Solutions [Member]
Segment Reporting Information [Line Items]
Sales	136,277	138,120	398,709	411,723
Gross Profit	65,289	62,151	195,804	179,984
Services & Support [Member]
Segment Reporting Information [Line Items]
Sales	32,613	19,958	75,086	49,328
Gross Profit	$ 10,519	$ 8,498	$ 24,753	$ 24,474

Segment Information - Sales Inf

Segment Information - Sales Information by Category (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenue from External Customer [Line Items]
Sales	$ 168,890	$ 158,078	$ 473,795	$ 461,051
Access & Aggregation [Member]
Revenue from External Customer [Line Items]
Sales	120,618	103,431	316,705	309,014
Customer Devices [Member]
Revenue from External Customer [Line Items]
Sales	32,984	35,545	106,213	97,291
Traditional & Other Products [Member]
Revenue from External Customer [Line Items]
Sales	$ 15,288	$ 19,102	$ 50,877	$ 54,746

Liability for Warranty Return68

Liability for Warranty Returns - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Product Warranties Disclosures [Abstract]
Period of warranty for product defects	90 days to ten years
Liability for warranty obligations	$ 8,752	$ 8,935	$ 8,739	$ 8,716	$ 8,933	$ 8,415

Liability for Warranty Return69

Liability for Warranty Returns - Summary of Warranty Expense and Write-Off Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Product Warranties Disclosures [Abstract]
Balance at beginning of period	$ 8,935	$ 8,933	$ 8,739	$ 8,415
Plus: Amounts charged to cost and expenses	4,012	777	6,341	1,905
Less: Deductions	(4,195)	(994)	(6,328)	(1,604)
Balance at end of period	$ 8,752	$ 8,716	$ 8,752	$ 8,716

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Sep. 30, 2016USD ($)EquityUnit
Contingencies And Commitments [Line Items]
Number of private equity funds | EquityUnit	2
Commitments towards private equity funds	$ 7.7
Investment Commitments [Member]
Contingencies And Commitments [Line Items]
Aggregate investment committed in private equity funds	7.9
Private Equity Funds [Member]
Contingencies And Commitments [Line Items]
Contribution to private equity funds	$ 8.4

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Nov. 08, 2016	Oct. 18, 2016	Sep. 30, 2016	Nov. 17, 2016
Subsequent Event [Line Items]
Dividend declaration date			Oct. 18, 2016
Dividend record date			Nov. 3, 2016
Dividend payment date			Nov. 17, 2016
Stock repurchased, shares			1,200,000
Shares repurchased, average price per share			$ 18.34
Additional shares authorized for purchase			4,600,000
Scenario Forecast [Member]
Subsequent Event [Line Items]
Quarterly dividend payable subsequent to balance sheet date				$ 4.3
Subsequent Events [Member]
Subsequent Event [Line Items]
Common stock dividends per share declared		$ 0.09
Stock repurchased, shares	200,000
Shares repurchased, average price per share	$ 17.96
Additional shares authorized for purchase	4,400,000