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, 2017	Dec. 31, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (39,067)	$ (58,987)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	(60,526)	13,584
Amounts reclassified from accumulated other comprehensive loss	1,567	6,336
Other comprehensive income (loss), net of tax	(58,959)	19,920
Ending balance	(98,026)	(39,067)
Foreign Currency Translation Component [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(4,661)	(23,411)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	(65,030)	18,750
Amounts reclassified from accumulated other comprehensive loss	0	0
Other comprehensive income (loss), net of tax	(65,030)	18,750
Ending balance	(69,691)	(4,661)
Pension and Other Postretirement Benefit Plans [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(34,406)	(35,576)
Other comprehensive gain (loss) loss attributable to Belden before reclassifications	4,504	(5,166)
Amounts reclassified from accumulated other comprehensive loss	1,567	6,336
Other comprehensive income (loss), net of tax	6,071	1,170
Ending balance	$ (28,335)	$ (34,406)