Income (loss) per Share - Basis for Income Per Share Computations (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 29, 2020
Numerator:
Income from continuing operations	$ 28,741	$ 14,891
Less: Net income (loss) attributable to noncontrolling interest	75	(30)
Income from continuing operations attributable to Belden stockholders	28,666	14,921
Add: Loss from discontinued operations, net of tax	0	(26,110)
Net income (loss) attributable to Belden stockholders	$ 28,666	$ (11,189)
Denominator:
Weighted average shares outstanding, basic (in shares)	44,679	45,390
Effect of dilutive common stock equivalents (in shares)	366	148
Weighted average shares outstanding, diluted (in shares)	45,045	45,538