Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 03, 2021	Sep. 27, 2020	Oct. 03, 2021	Sep. 27, 2020
Income Statement [Abstract]
Revenues	$ 630,835	$ 475,839	$ 1,769,190	$ 1,364,176
Cost of sales	(407,559)	(308,247)	(1,143,035)	(876,143)
Gross profit	223,276	167,592	626,155	488,033
Selling, general and administrative expenses	(109,963)	(85,037)	(313,966)	(275,129)
Research and development expenses	(32,451)	(30,324)	(94,873)	(81,633)
Amortization of intangibles	(9,696)	(16,104)	(28,745)	(48,306)
Operating income	71,166	36,127	188,571	82,965
Interest expense, net	(16,251)	(15,607)	(46,640)	(43,188)
Loss on debt extinguishment	(5,715)	0	(5,715)	0
Non-operating pension benefit	992	680	3,121	2,079
Income from continuing operations before taxes	50,192	21,200	139,337	41,856
Income tax expense	(8,875)	(631)	(25,307)	(3,223)
Income from continuing operations	41,317	20,569	114,030	38,633
Loss from discontinued operations, net of tax	0	(6,231)	0	(103,395)
Gain on disposal of discontinued operations, net of tax	0	2,743	0	2,743
Net income (loss)	41,317	17,081	114,030	(62,019)
Less: Net income attributable to noncontrolling interest	53	85	336	79
Net income (loss) attributable to Belden stockholders	$ 41,264	$ 16,996	$ 113,694	$ (62,098)
Weighted average number of common shares and equivalents:
Basic (in shares)	44,851	44,567	44,762	44,834
Diluted (in shares)	45,425	44,709	45,242	44,968
Basic income (loss) per share attributable to Belden stockholders:
Continuing operations (in dollars per share)	$ 0.92	$ 0.46	$ 2.54	$ 0.86
Discontinued operations (in dollars per share)	0	(0.14)	0	(2.31)
Disposal of discontinued operations (in dollars per share)	0	0.06	0	0.06
Net income (loss) (in dollars per share)	0.92	0.38	2.54	(1.39)
Diluted income (loss) per share attributable to Belden stockholders:
Continuing operation (in dollars per share)	0.91	0.46	2.51	0.86
Discontinued operations (in dollars per share)	0	(0.14)	0	(2.31)
Disposal of discontinued operations (in dollars per share)	0	0.06	0	0.06
Net income (loss) (in dollars per share)	$ 0.91	$ 0.38	$ 2.51	$ (1.39)
Comprehensive income (loss) attributable to Belden	$ 69,390	$ (34,921)	$ 174,280	$ (136,138)
Common stock dividends declared per share (in dollars per share)	$ 0.05	$ 0.05	$ 0.15	$ 0.15