Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss), Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 1,387,588	$ 1,434,866
Other comprehensive loss, net of tax	29,010	(31,392)
Ending balance	1,431,329	$ 1,292,146
Foreign Currency Translation Component
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(41,882)
Other comprehensive income attributable to Belden before reclassifications	28,790
Amounts reclassified from accumulated other comprehensive income	0
Other comprehensive loss, net of tax	28,790
Ending balance	(13,092)
Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(33,025)
Other comprehensive income attributable to Belden before reclassifications	0
Amounts reclassified from accumulated other comprehensive income	219
Other comprehensive loss, net of tax	219
Ending balance	(32,806)
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(74,907)
Other comprehensive income attributable to Belden before reclassifications	28,790
Amounts reclassified from accumulated other comprehensive income	219
Other comprehensive loss, net of tax	29,009
Ending balance	$ (45,898)