Acquisitions - Schedule of Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Business Acquisition [Line Items]
Document Period End Date			Jun. 30, 2019
Opterna International Corp.
Business Acquisition [Line Items]
Revenues	$ 637,530	$ 675,343	$ 1,233,321	$ 1,287,431
Net income attributable to Belden common stockholders	$ 36,045	$ 19,977	$ 52,531	$ 11,664
Diluted income (loss) per share attributable to Belden common stockholders (in usd per share)	$ 0.91	$ 0.49	$ 1.33	$ 0.28
Snell Advanced Media
Business Acquisition [Line Items]
Revenues		$ 671,441		$ 1,285,625
Net income attributable to Belden common stockholders		$ 35,241		$ 34,169
Diluted income (loss) per share attributable to Belden common stockholders (in usd per share)		$ 0.86		$ 0.82