Comprehensive Income and Accumulated Other Comprehensive Income (Loss) - Total Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Equity [Abstract]
Net income	$ 28,792	$ 35,891	$ 31,362	$ 61,472
Foreign currency translation gain (loss), net of $0.6 million, $0.5 million, $1.1 million, and $0.4 million tax, respectively	60,642	(17,107)	28,847	(26,943)
Adjustments to pension and postretirement liability, net of $0.2 million, $0.3 million, $0.5 million, and $0.5 million tax, respectively	369	406	772	774
Total comprehensive income	89,803	19,190	60,981	35,303
Less: Comprehensive loss attributable to noncontrolling interest	(94)	(77)	(126)	(240)
Comprehensive income attributable to Belden	89,897	19,267	61,107	35,543
Foreign currency translation, tax income (loss)	600	500	1,100	400
Adjustments to pension and postretirement liability, tax	$ 200	$ 300	$ 500	$ 500