Income Per Share - Basis for Income Per Share Computations (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Numerator:
Net income (loss)	$ (297,015)	$ 85,858	$ (229,547)	$ 117,220
Less: Net income (loss) attributable to noncontrolling interests	(6)	(23)	60	(148)
Less: Preferred stock dividends	971	8,732	18,437	26,198
Net income (loss) attributable to Belden common stockholders	(297,980)	77,149	(248,044)	91,170
Plus Preferred stock dividends	0	8,732	0	0
Net income (loss) attributable to Belden common stockholders, diluted	$ (297,980)	$ 85,881	$ (248,044)	$ 91,170
Denominator:
Weighted average shares outstanding, basic (in shares)	44,444	40,510	41,090	40,960
Assumed conversion of preferred stock into common stock (in shares)	0	6,857	0	0
Effect of dilutive common stock equivalents (in shares)	0	311	0	308
Weighted average shares outstanding, diluted (in shares)	44,444	47,678	41,090	41,268