Net Investment Hedge	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net Investment Hedge	Net Investment HedgeAll of our euro denominated notes were issued by Belden Inc., a USD functional currency entity. As of December 31, 2020, €767.8 million of our outstanding foreign denominated debt is designated as a net investment hedge on the foreign currency risk of our net investment in our euro foreign operations. The objective of the hedge is to protect the net investment in the foreign operation against adverse changes in the euro exchange rate. The transaction gain or loss is reported in the translation adjustment section of other comprehensive income. For the years ended December 31, 2020, 2019 and 2018, the transaction gain/(loss) associated with the net investment hedge reported in other comprehensive income was $(56.2) million, $26.6 million and $87.5 million, respectively. During 2020, we de-designated €532.2 million of our outstanding debt that was previously designated as a net investment hedge. After the de-designation, transaction gains or losses associated with this €532.2 million of debt are reported in income from continuing operations.