Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Income Statement [Abstract]
Revenues	$ 601,974	$ 424,811	$ 1,138,355	$ 888,337
Cost of sales	(390,439)	(274,871)	(735,476)	(567,896)
Gross profit	211,535	149,940	402,879	320,441
Selling, general and administrative expenses	(105,554)	(91,703)	(204,003)	(190,092)
Research and development expenses	(30,922)	(25,090)	(62,422)	(51,309)
Amortization of intangibles	(9,102)	(16,017)	(19,049)	(32,202)
Operating income	65,957	17,130	117,405	46,838
Interest expense, net	(14,878)	(14,257)	(30,389)	(27,581)
Non-operating pension benefit	1,445	700	2,129	1,399
Income from continuing operations before taxes	52,524	3,573	89,145	20,656
Income tax expense	(8,552)	(400)	(16,432)	(2,592)
Income from continuing operations	43,972	3,173	72,713	18,064
Loss from discontinued operations, net of tax	0	(71,054)	0	(97,164)
Net income (loss)	43,972	(67,881)	72,713	(79,100)
Less: Net income (loss) attributable to noncontrolling interest	208	24	283	(6)
Net income (loss) attributable to Belden stockholders	$ 43,764	$ (67,905)	$ 72,430	$ (79,094)
Weighted average number of common shares and equivalents:
Basic (in shares)	44,759	44,557	44,717	44,969
Diluted (in shares)	45,262	44,665	45,162	45,097
Basic income (loss) per share attributable to Belden stockholders:
Continuing operations (in dollars per share)	$ 0.98	$ 0.07	$ 1.62	$ 0.40
Discontinued operations (in dollars per share)	0	(1.59)	0	(2.16)
Net income (loss) (in dollars per share)	0.98	(1.52)	1.62	(1.76)
Diluted income (loss) per share attributable to Belden stockholders:
Continuing operation (in dollars per share)	0.97	0.07	1.60	0.40
Discontinued operations (in dollars per share)	0	(1.59)	0	(2.16)
Net income (loss) (in dollars per share)	$ 0.97	$ (1.52)	$ 1.60	$ (1.76)
Comprehensive income (loss) attributable to Belden	$ 22,499	$ (112,351)	$ 104,890	$ (101,217)
Common stock dividends declared per share (in dollars per share)	$ 0.05	$ 0.05	$ 0.10	$ 0.10