Document and Entity Information - USD ($)

12 Months Ended

Dec. 31, 2020

Feb. 24, 2021

Jun. 30, 2020

Cover [Abstract]

Document Type

10-K

Amendment Flag

false

Document Period End Date

Dec. 31, 2020

Document Fiscal Year Focus

2020

Document Fiscal Period Focus

FY

Trading Symbol

ADTN

Entity Registrant Name

ADTRAN, Inc.

Entity Central Index Key

0000926282

Current Fiscal Year End Date

--12-31

Entity Well-known Seasoned Issuer

Yes

Entity Current Reporting Status

Yes

Entity Voluntary Filers

No

Entity Filer Category

Accelerated Filer

Entity Shell Company

false

Entity Emerging Growth Company

false

Entity Small Business

false

ICFR Auditor Attestation Flag

true

Entity Common Stock, Shares Outstanding

48,337,561

Entity Public Float

$ 520,493,715

Entity Interactive Data Current

Yes

Entity File Number

000-24612

Entity Tax Identification Number

63-0918200

Entity Address, Address Line One

901 Explorer Boulevard

Entity Address, City or Town

Huntsville

Entity Address, State or Province

AL

Entity Address, Postal Zip Code

35806-2807

City Area Code

256

Local Phone Number

963-8000

Entity Incorporation, State or Country Code

DE

Document Annual Report

true

Document Transition Report

false

Title of 12(b) Security

Common Stock, Par Value $0.01

Security Exchange Name

NASDAQ

Documents Incorporated by Reference

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Proxy Statement for the Annual Meeting of Stockholders to be held on May 12, 2021 are incorporated herein by reference in Part III.