Days after the effective date of a merger, in which any shareholder who has not commenced an appraisal proceeding or joined the proceeding as a named party shall have the right to withdraw such stockholder's demand for appraisal and to accept the terms offered upon the merger.

No definition available.

Mergers and Acquisitions (Narrative) (Details) $ / shares in Units, $ in Millions			4 Months Ended	12 Months Ended
	Dec. 08, 2016 USD ($) plaintiff $ / shares shares	Nov. 12, 2015 USD ($) shares	Mar. 31, 2017 USD ($) shares	Mar. 31, 2017 USD ($) shares	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)
Business Acquisition [Line Items]
Petitions filed \| plaintiff	5
Accrued merger consideration payable			$ 812.9	$ 812.9	$ 0.0
Goodwill			2,700.5	2,700.5	534.8	$ 323.4
Principal amount of debt outstanding			$ 3,107.5	$ 3,107.5	786.0
Interest Rate, Percentage Spread on Federal Reserve Discount Rate			5.00%	5.00%
Starz
Business Acquisition [Line Items]
Cash consideration	$ 1,176.1
Goodwill	$ 2,165.7
Revenue since acquisition			$ 483.2
Income before income taxes since acquisition			$ 79.4
Starz \| Acquisition-related Costs
Business Acquisition [Line Items]
Merger-related transaction costs				$ 70.9
Starz \| Starz Series A Common Stock
Business Acquisition [Line Items]
Cash to be paid per outstanding share (in usd per share) \| $ / shares	$ 18.00
Cash consideration	$ 1,123.3
Starz \| Starz Series B Common Stock
Business Acquisition [Line Items]
Cash to be paid per outstanding share (in usd per share) \| $ / shares	$ 7.26
Cash consideration	$ 52.8
Starz \| Class A Voting Shares
Business Acquisition [Line Items]
Lionsgate share price (in usd per share) \| $ / shares	$ 26.48
Starz \| Class A Voting Shares \| Common Stock
Business Acquisition [Line Items]
Conversion of Stock, Shares Issued \| shares	0.5
Starz \| Class A Voting Shares \| Starz Series B Common Stock
Business Acquisition [Line Items]
Conversion of stock, shares converted \| shares	0.6321
Starz \| Class B Non-Voting Shares
Business Acquisition [Line Items]
Lionsgate share price (in usd per share) \| $ / shares	$ 25.70
Starz \| Class B Non-Voting Shares \| Common Stock
Business Acquisition [Line Items]
Conversion of Stock, Shares Issued \| shares	0.5
Starz \| Class B Non-Voting Shares \| Starz Series A Common Stock
Business Acquisition [Line Items]
Conversion of stock, shares converted \| shares	0.6784
Starz \| Class B Non-Voting Shares \| Starz Series B Common Stock
Business Acquisition [Line Items]
Conversion of stock, shares converted \| shares	0.6321
Starz \| Common Stock
Business Acquisition [Line Items]
Lionsgate share price (in usd per share) \| $ / shares	$ 26.09
Pilgrim Media Group
Business Acquisition [Line Items]
Purchase price, common shares issued or issuable (in shares) \| shares		1,517,451
Cash consideration		$ 144.7
Percentage of interest acquired		62.50%
Aggregate purchase price		$ 201.7
Purchase price, common shares issued, value assigned		57.0
Pilgrim Media Group \| Transactional Costs
Business Acquisition [Line Items]
Acquisition related and transactional costs		$ 7.7		$ 3.4
Customer relationships \| Starz
Business Acquisition [Line Items]
Weighted-average useful life	17 years
Starz Dissenting Shareholders \| Starz
Business Acquisition [Line Items]
Purchase price, common shares issued or issuable (in shares) \| shares	15,300,000
Outstanding equity interests (in shares) \| shares	25,000,000		22,500,000	22,500,000
Accrued merger consideration payable	$ 797.3		$ 812.9	$ 812.9
Period for demanding appraisal rights				60 days
Shareholders withdrawing demands of appraisal rights (in shares) \| shares			2,510,485	2,510,485
Revolving Credit Facility
Business Acquisition [Line Items]
Principal amount of debt outstanding			$ 0.0	$ 0.0	$ 161.0
Outstanding obligations	241.0
Revolving Credit Facility \| Starz
Business Acquisition [Line Items]
Outstanding obligations	255.0
Starz Senior Notes \| Senior Notes
Business Acquisition [Line Items]
Principal amount of debt outstanding	$ 675.0