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, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,434,866	$ 1,461,317
Ending balance	1,387,588	1,434,866
Foreign Currency Translation Component
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(69,691)	(4,661)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	27,809	(65,030)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net current period other comprehensive gain (loss) attributable to Belden	27,809	(65,030)
Ending balance	(41,882)	(69,691)
Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(28,335)	(34,406)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	(7,813)	4,504
Amounts reclassified from accumulated other comprehensive income (loss)	3,123	1,567
Net current period other comprehensive gain (loss) attributable to Belden	(4,690)	6,071
Ending balance	(33,025)	(28,335)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(98,026)	(39,067)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	19,996	(60,526)
Amounts reclassified from accumulated other comprehensive income (loss)	3,123	1,567
Net current period other comprehensive gain (loss) attributable to Belden	23,119	(58,959)
Ending balance	$ (74,907)	$ (98,026)