Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Total Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Equity [Abstract]
Net income	$ 85,858	$ 945	$ 117,220	$ 62,417
Foreign currency translation gain (loss), net of $0.5 million, $1.1 million, $0.7 million, and $1.5 million tax, respectively	(17,904)	(19,535)	10,943	(46,478)
Adjustments to pension and postretirement liability, net of $0.4 million, $0.2 million, $0.9 million, and $0.7 million tax, respectively	637	397	1,409	1,171
Total comprehensive income (loss)	68,591	(18,193)	129,572	17,110
Less: Comprehensive loss attributable to noncontrolling interest	(29)	(66)	(155)	(306)
Comprehensive income (loss) attributable to Belden	68,620	(18,127)	129,727	17,416
Foreign currency translation, tax income (loss)	500	1,100	700	1,500
Adjustments to pension and postretirement liability, tax	$ 400	$ 200	$ 900	$ 700