Acquisitions - Pro Forma Effect on Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Thinklogical Holdings LLC [Member]
Business Acquisition [Line Items]
Revenues	$ 2,399,715	$ 2,407,830
Net income attributable to Belden common stockholders	$ 60,690	$ 113,014
Diluted income per share attributable to Belden common stockholders	$ 1.42	$ 2.66
Tripwire [Member]
Business Acquisition [Line Items]
Revenues			$ 2,354,191
Net income attributable to Belden common stockholders			$ 92,104
Diluted income per share attributable to Belden common stockholders			$ 2.14