Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Oct. 03, 2021	Jan. 29, 2021	Dec. 31, 2020
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Goodwill	$ 1,283,364		$ 1,251,938
OTN Systems N.V.
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Receivables		$ 5,036
Inventories		10,700
Other current assets		1,361
Property, plant and equipment		602
Intangible assets		39,930
Goodwill		38,915
Operating lease right-of-use assets		4,144
Other long-lived assets		706
Total assets acquired		101,394
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Accounts payable		5,931
Accrued liabilities		4,485
Deferred revenues		3,260
Long-term debt		1,841
Post retirement benefits		3,581
Deferred income taxes		4,889
Long-term operating lease liabilities		3,271
Other long-term liabilities		771
Total liabilities assumed		28,029
Net assets		73,365
Noncontrolling interests		20
Net assets attributable to Belden		$ 73,345