Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 29, 2020
Income Statement [Abstract]
Revenues	$ 536,381	$ 463,526
Cost of sales	(345,037)	(293,025)
Gross profit	191,344	170,501
Selling, general and administrative expenses	(98,449)	(98,389)
Research and development expenses	(31,500)	(26,219)
Amortization of intangibles	(9,947)	(16,185)
Operating income	51,448	29,708
Interest expense, net	(15,511)	(13,324)
Non-operating pension benefit	684	699
Income from continuing operations before taxes	36,621	17,083
Income tax expense	(7,880)	(2,192)
Income from continuing operations	28,741	14,891
Loss from discontinued operations, net of tax	0	(26,110)
Net income (loss)	28,741	(11,219)
Less: Net income (loss) attributable to noncontrolling interest	75	(30)
Net income (loss) attributable to Belden stockholders	$ 28,666	$ (11,189)
Weighted average number of common shares and equivalents:
Basic (in shares)	44,679	45,390
Diluted (in shares)	45,045	45,538
Basic income (loss) per share attributable to Belden stockholders:
Continuing operations (in dollars per share)	$ 0.64	$ 0.33
Discontinued operations (in dollars per share)	0	(0.58)
Net income (loss) (in dollars per share)	0.64	(0.25)
Diluted income (loss) per share attributable to Belden stockholders:
Continuing operation (in dollars per share)	0.64	0.33
Discontinued operations (in dollars per share)	0	(0.58)
Net income (loss) (in dollars per share)	$ 0.64	$ (0.25)
Comprehensive income attributable to Belden	$ 82,391	$ 11,134
Common stock dividends declared per share (in dollars per share)	$ 0.05	$ 0.05