Acquisitions - Additional Information (Details) - USD ($)						3 Months Ended						9 Months Ended
	Sep. 25, 2019	Apr. 15, 2019	Apr. 05, 2019	Apr. 25, 2018	Feb. 08, 2018	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Sep. 29, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Purchase price, net of cash acquired												$ 50,951,000	$ 84,580,000
Severance, restructuring, and acquisition integration costs						$ 4,045,000			$ 11,688,000			10,904,000	57,010,000
Amortization of intangibles						22,243,000			25,533,000			67,952,000	74,990,000
Net income (loss)						(297,015,000)	$ 42,290,000	$ 25,178,000	85,858,000	$ 28,792,000	$ 2,570,000	(229,547,000)	117,220,000
Opterna International Corp.
Business Acquisition [Line Items]
Percentage of outstanding shares acquired		100.00%
Purchase price, net of cash acquired		$ 51,700,000
Acquisition price paid	$ 400,000	45,500,000
Maximum earnout consideration		25,000,000.0
Estimated earnout consideration		5,800,000
Adjustment to goodwill						(9,400,000)
Receivables		5,308,000
Property, plant, and equipment		1,328,000
Tax basis in acquired goodwill		$ 0
Post acquisition revenue of acquiree						9,100,000						17,900,000
Post acquisition income (loss) before taxes of acquiree						(200,000)						(300,000)
Net income attributable to Belden common stockholders						(295,312,000)			77,417,000			(242,579,000)	87,250,000
Amortization of intangibles						1,400,000						2,300,000
Inventory adjustment						(100,000)						500,000
Net income (loss)						0.0						100,000
Net-Tech Technology, Inc.
Business Acquisition [Line Items]
Percentage of outstanding shares acquired				100.00%
Acquisition price paid				$ 8,500,000
Snell Advanced Media
Business Acquisition [Line Items]
Percentage of outstanding shares acquired					100.00%
Acquisition price					$ 104,600,000
Acquisition price paid					75,200,000
Maximum earnout consideration					31,400,000
Estimated earnout consideration					29,300,000
Long-term debt acquired					19,315,000
Receivables					16,551,000
Property, plant, and equipment					7,716,000
Tax basis in acquired goodwill					$ 0
Post acquisition revenue of acquiree									25,300,000				77,200,000
Severance, restructuring, and acquisition integration costs									7,100,000				36,600,000
Net income attributable to Belden common stockholders									92,769,000				126,937,000
Amortization of intangibles									3,700,000				8,700,000
Inventory adjustment									$ 600,000				$ 1,800,000
Suttle, Inc. Asset Acquisition
Business Acquisition [Line Items]
Asset acquisition, consideration transferred			$ 5,000,000.0
PPC Broadband and Opterna Integration Program
Business Acquisition [Line Items]
Severance, restructuring, and acquisition integration costs						$ 3,100,000						$ 5,600,000