Basis of Presentation (Details Textuals) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended				3 Months Ended	6 Months Ended			6 Months Ended
	Sep. 30, 2011	Oct. 01, 2010	Sep. 30, 2011 Year Month	Oct. 01, 2010	Apr. 01, 2011	Sep. 30, 2011 Accounting Standards Update No 2009-13 [Member]	Sep. 30, 2011 Accounting Standards Update No 2011-04 [Member]	Sep. 30, 2011 Accounting Standards Update No 2011-05 [Member]	Sep. 30, 2011 Accounting Standards Update No 2011-08 [Member]	Jul. 02, 2010 Government satellite communication program [Member]	Oct. 01, 2010 Government satellite communication program [Member]	Sep. 30, 2011 Customer Premise Equipment [Member] Year	Apr. 01, 2011 Customer Premise Equipment [Member]	Sep. 30, 2011 Common Stock Held in Treasury [Member]	Oct. 01, 2010 Common Stock Held in Treasury [Member]	Apr. 01, 2011 Common Stock Held in Treasury [Member]
Recent authoritative guidance
Description of new accounting pronouncements						In October 2009, the FASB issued authoritative guidance for revenue recognition with multiple deliverables (ASU 2009-13, which updated ASC 605-25). This new guidance impacts the determination of when the individual deliverables included in a multiple-element arrangement may be treated as separate units of accounting. Additionally, this guidance modifies the manner in which the transaction consideration is allocated across the separately identified deliverables by no longer permitting the residual method of allocating arrangement consideration. The Company adopted this guidance in the first quarter of fiscal year 2012 without a material impact on its consolidated financial statements and disclosures.	In May 2011, the FASB issued ASU 2011-04, Fair Value Measurement (ASC 820): Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in GAAP and International Financial Reporting Standards (IFRS). The new authoritative guidance results in a consistent definition of fair value and common requirements for measurement of and disclosure about fair value between GAAP and IFRS. While many of the amendments to GAAP are not expected to have a significant effect on practice, the new guidance changes some fair value measurement principles and disclosure requirements. This guidance is effective for the Company beginning in the fourth quarter of fiscal year 2012. Adoption of this authoritative guidance is not expected to have a material impact on the Company’s consolidated financial statements and disclosures.	In June 2011, the FASB issued ASU 2011-05, Comprehensive Income (Topic ASC 220): Presentation of Comprehensive Income. The new authoritative guidance requires an entity to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. The new authoritative guidance eliminates the option to present the components of other comprehensive income as part of the statement of equity. This guidance will be effective for the Company beginning in the fourth quarter of fiscal year 2012 and should be applied retrospectively; however, early adoption is permitted. The Company is currently evaluating the impact that the authoritative guidance may have on its consolidated financial statements and disclosures.	In September 2011, the FASB issued ASU No. 2011-08, Intangibles—Goodwill and Other (ASU 2011-08): Testing Goodwill for Impairment. The new authoritative guidance simplifies how an entity tests goodwill for impairment. The new authoritative guidance allows an entity to first assess qualitative factors to determine whether it is necessary to perform the two-step quantitative goodwill impairment test. The two-step quantitative impairment test is required only if, based on its qualitative assessment, an entity determines that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. This guidance is effective for interim and annual goodwill impairment tests performed for fiscal years beginning after December 15, 2011. The Company is currently evaluating the impact that the authoritative guidance may have on its consolidated financial statements and disclosures. Adoption of this authoritative guidance is not expected to have a material impact on the Company’s consolidated financial statements and disclosures.
Revenue Recognition [Line Items]
Forward loss related to loss contracts	$ 400,000	$ 500,000	$ 700,000	$ 9,200,000						$ 8,500,000	$ 8,500,000
Property, Plant and Equipment [Line Items]
Total accumulated depreciation of CPE	178,176,000		178,176,000		149,238,000							26,300,000	19,200,000
Equity, Class of Treasury Stock [Line Items]
Repurchase of common stock														51,403	58,380
Purchase of treasury shares pursuant to vesting of certain RSU agreements			2,250,000											2,250,000	1,900,000
Repurchased shares of common stock held in treasury														611,766		560,363
Basis of Presentation (Textuals) [Abstract]
Total US government contract-related reserves balance	6,700,000		6,700,000		6,700,000
Property, equipment and satellites, estimated useful life minimum (years)			1									3
Property, equipment and satellites, estimated useful life maximum (years)			24									5
Defense Contract Audit Agency Completed Cost Audits			Contract costs on U.S. government contracts are subject to audit and negotiations with U.S. government representatives. The Company’s incurred cost audits by the Defense Contract Audit Agency (DCAA) have not been completed for fiscal year 2003 and subsequent fiscal years. Although the Company has recorded contract revenues subsequent to fiscal year 2002 based upon an estimate of costs that the Company believes will be approved upon final audit or review, the Company does not know the outcome of any ongoing or future audits or reviews and adjustments, and if future adjustments exceed the Company’s estimates, its profitability would be adversely affected.
CPE leased equipment, total cost	68,477,000		68,477,000		61,610,000
Capitalized interest expense	7,700,000	6,700,000	15,300,000	12,700,000
Capital Leases	3,100,000		3,100,000		3,100,000
Capital lease accumulated amortization	400,000		400,000		0
Total capitalized costs related to patents	3,200,000		3,200,000		3,200,000
Total capitalized costs related to licenses	5,900,000		5,900,000		5,700,000
Accumulated amortization of patents and other licenses	400,000		400,000		300,000
Amortization expense related to patents and other licenses	0	0	100,000	100,000
Capitalized costs, net, related to software developed for resale	31,500,000		31,500,000		24,500,000
Capitalized cost related to software development for resale	4,100,000	4,100,000	9,400,000	8,000,000
Amortization expense of software development costs	1,100,000	0	2,300,000	0
Self-insurance liability	1,500,000		1,500,000		1,500,000
Accrued indemnification losses	0		0		0
Amount payable under indemnification agreement recorded as accrued liability	500,000		500,000		500,000
Maximum amount payable under indemnification agreement	500,000		500,000		500,000
Common stock issued based on the vesting terms of certain restricted stock unit agreements			145,695	159,235
Notional value of foreign currency forward contracts	12,600,000		12,600,000		4,600,000
Foreign currency forward contracts maturity			18 months
Estimated net existing income expected to be reclassified into income within the next twelve months	400,000		400,000
Gains or losses from ineffectiveness of derivative instruments	0	0	0	0
Recognized stock based compensation expense	4,800,000	4,100,000	8,979,000	8,313,000
Incremental tax benefit from stock options exercised and restricted stock unit awards vesting			$ 0	$ 0
Life over which software development costs are amortized once product is available for general release			5