Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss), Net of Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,387,588	$ 1,434,866
Ending balance	965,819	1,387,588
Foreign Currency Translation Component
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(41,882)	(69,691)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	23,657	27,809
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net current period other comprehensive gain (loss) attributable to Belden	23,657	27,809
Ending balance	(18,225)	(41,882)
Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(33,025)	(28,335)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	(13,281)	(7,813)
Amounts reclassified from accumulated other comprehensive income (loss)	1,113	3,123
Net current period other comprehensive gain (loss) attributable to Belden	(12,168)	(4,690)
Ending balance	(45,193)	(33,025)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(74,907)	(98,026)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	10,376	19,996
Amounts reclassified from accumulated other comprehensive income (loss)	1,113	3,123
Net current period other comprehensive gain (loss) attributable to Belden	11,489	23,119
Ending balance	$ (63,418)	$ (74,907)