Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Total Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jul. 01, 2018	Apr. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Equity [Abstract]
Net income	$ 42,290	$ 25,178	$ 28,792	$ 2,570	$ 67,468	$ 31,362
Foreign currency translation gain (loss), net of $0.4 million, $0.6 million, $0.8 million, and $1.1 million tax, respectively	(16,904)		60,642		11,887	28,847
Adjustments to pension and postretirement liability, net of $0.1 million, $0.2 million, $0.1 million, and $0.5 million tax, respectively	251		369		470	772
Total comprehensive income	25,637		89,803		79,825	60,981
Less: Comprehensive income (loss) attributable to noncontrolling interests	130		(94)		107	(126)
Comprehensive income attributable to Belden	25,507		89,897		79,718	61,107
Foreign currency translation, tax income (loss)	400		600		800	1,100
Adjustments to pension and postretirement liability, tax	$ 100		$ 200		$ 100	$ 500