Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Dec. 28, 2012	Mar. 30, 2012 Fair Value, Inputs, Level 1 [Member] Fair Value, Measurements, Recurring [Member] 2016 Notes [Member]	Dec. 28, 2012 Fair Value, Inputs, Level 1 [Member] Fair Value, Measurements, Recurring [Member] Initial 2020 Notes [Member]	Mar. 30, 2012 Fair Value, Inputs, Level 2 [Member] Fair Value, Measurements, Recurring [Member] Initial 2020 Notes [Member]	Dec. 28, 2012 Fair Value, Inputs, Level 2 [Member] Fair Value, Measurements, Recurring [Member] Additional 2020 Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of outstanding long-term debt related to the Senior Notes		$ 298.4	$ 287.4	$ 280.2	$ 313.5
Interest on satellite in orbital performance obligation	7.00%
Period of in orbit performance incentive payments including interest	15 years

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant