Income Per Share - Basis for Income Per Share Computations (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Numerator:
Net income	$ 85,858	$ 945	$ 117,220	$ 62,417
Less: Net loss attributable to noncontrolling interest	(23)	(82)	(148)	(274)
Less: Preferred stock dividends	8,732	8,732	26,198	26,198
Net income (loss) attributable to Belden common stockholders	77,149	(7,705)	91,170	36,493
Plus: Preferred stock dividends	8,732	0	0	0
Net income (loss) attributable to Belden common stockholders for diluted income (loss) per share	$ 85,881	$ (7,705)	$ 91,170	$ 36,493
Denominator:
Weighted average shares outstanding, basic (in shares)	40,510	42,256	40,960	42,251
Assumed conversion of preferred stock into common stock (in shares)	6,857	0	0	0
Effect of dilutive common stock equivalents (in shares)	311	0	308	412
Weighted average shares outstanding, diluted (in shares)	47,678	42,256	41,268	42,663