Additional Financial Information (Non-cash Investing and Financing Activities) (Details) - USD ($) $ in Millions	9 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Non-cash investing activities
Decrease in finance lease right-of-use asset due to a reassessment event	$ (42.0)	$ 0.0
Non-cash financing activities
Decrease in finance lease liability due to a reassessment event	$ (48.6)	$ 0.0

Finance Lease, Right-of-Use Asset, Increase (Decrease) From Reclassification

No definition available.

Name:	lgfa_FinanceLeaseRightOfUseAssetIncreaseDecreaseFromReclassification
Namespace Prefix:	lgfa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration