Alabama State Industrial Development Authority Financing and Economic Incentives - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2008	Jan. 13, 1995
Debt Instrument [Line Items]
Proceeds from state industrial development authority issued taxable bonds loaned to ADTRAN					$ 20,000,000
Amount of outstanding bonds issued by Banks for Authority				50,000,000
Percentage of interest Amended and Restated Bond bears	5.00%
Maturity date of Amended and Restated Bond	Jan. 01, 2020
Estimated fair value of bond	48,800,000
Restricted certificate of deposit held	48,250,000	48,250,000
Total realized economic incentives	1,400,000	1,900,000	1,500,000
Bond debt outstanding classified as current liability	500,000	500,000
Payments on long-term debt	$ 500,000	$ 1,000,000	$ 250,000