The Company and a Summary of Its Significant Accounting Policies - Additional Information (Detail)						1 Months Ended	12 Months Ended
	Mar. 03, 2017 USD ($)	Mar. 01, 2017 USD ($) a	Nov. 23, 2016 USD ($) shares	Nov. 14, 2016 USD ($) shares	Oct. 06, 2015 USD ($) a	Nov. 30, 2016 USD ($)	Mar. 31, 2017 USD ($) shares	Mar. 31, 2016 USD ($)	Apr. 03, 2015 USD ($)	Jun. 30, 2016 USD ($)
Company And Summary Of Significant Accounting Policies [Line Items]
Shares issued in connection with acquisition of business, net of issuance costs							$ 4,988,000
Payment related to acquisition of business, net of cash acquired							16,528,000	$ 4,402,000	$ 57,376,000
Common stock issued under public offering, net of issuance costs							503,061,000
Payment related to acquisition of business, net of cash acquired							140,378,000	1,258,000
Capitalized interest expense							49,700,000	30,100,000	16,200,000
Number of acres land purchased | a					23
Purchased land value at cost					$ 39,500,000
Number of acres land sold | a		16
Proceed from sale of land		$ 27,600,000					$ 27,559,000
Initial term of operating leases							10 years
Total capitalized costs related to patents							$ 3,200,000	3,200,000
Total capitalized costs related to orbital slots and other licenses							15,400,000	15,400,000
Accumulated amortization of patents, orbital slots and other licenses							2,100,000	1,700,000
Debt issuance costs capitalized							6,100,000		3,500,000
Goodwill and other intangible assets impairment							$ 0	0	0
Maximum warranty periods provided on limited warranty							5 years
Forward loss related to loss contracts							$ 6,000,000	5,100,000	600,000
Defense contract audit agency completed cost audits							Contract costs on U.S. government contracts are subject to audit and review by the Defense Contracting Management Agency (DCMA), the Defense Contract Audit Agency (DCAA), and other U.S. government agencies, as well as negotiations with U.S. government representatives. The Company’s incurred cost audits by the DCAA have not been concluded for fiscal year 2016. As of March 31, 2017, the DCAA had completed its incurred cost audit for fiscal year 2004 and approved the Company’s incurred cost claims for fiscal years 2005 through 2015 without further audit. Although the Company has recorded contract revenues subsequent to fiscal year 2015 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.
Advertising costs							$ 4,800,000	$ 12,200,000	$ 17,000,000
Government Contracts Concentration Risk [Member] | Sales Revenue, Net [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage							28.80%	23.70%	22.80%
Government Contracts Concentration Risk [Member] | Accounts Receivable [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage							30.10%	22.80%
Customer Concentration Risk [Member] | Sales Revenue, Net [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage							19.60%	19.40%	21.10%
Minimum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)							2 years
Initial term of operating leases							1 year
Maximum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)							24 years
Initial term of operating leases							15 years
Property and Equipment, Net [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property and equipment							$ 1,202,589,000	$ 1,050,886,000
Accumulated depreciation and amortization							$ 661,981,000	563,976,000
CPE Leased Equipment [Member] | Minimum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)							4 years
CPE Leased Equipment [Member] | Maximum [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property, equipment and satellites, estimated useful life (years)							5 years
CPE Leased Equipment [Member] | Property and Equipment, Net [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Property and equipment							$ 271,917,000	260,409,000
Accumulated depreciation and amortization							$ 158,200,000	136,400,000
Common Stock [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Shares issued in connection with acquisition of business, net of issuance costs | shares							61,888
Common stock issued under public offering, net of issuance costs | shares			7,475,000				7,475,000
Common stock issued under public offering, net of issuance costs							$ 1,000
Paid-in Capital [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Shares issued in connection with acquisition of business, net of issuance costs							4,988,000
Common stock issued under public offering, net of issuance costs			$ 503,100,000				503,060,000
Revolving Credit Facility [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Payments of revolving credit facility borrowings						$ 225,000,000	$ 270,000,000	205,000,000	$ 245,000,000
Euro Retail Co [Member] | Eutelsat [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Ownership percentage of issued shares of an entity	49.00%
Arconics [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Purchase price of acquisition of business				$ 21,600,000
Shares issued in connection with acquisition of business, net of issuance costs				$ 5,000,000
Shares issued in connection with acquisition of business, net of issuance costs | shares				61,888
Cash consideration related to acquisition of business				$ 16,600,000
Cash acquired from acquisition of business				600,000
Payment related to acquisition of business, net of cash acquired				$ 16,000,000
Engreen [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Purchase price of the acquisition										$ 5,300,000
Euro Infrastructure Co [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
Ownership percentage of issued shares of an entity	49.00%						49.00%
Payments, net of transaction costs, to acquire the issued shares in investment	$ 139,500,000
Transaction costs	2,400,000
Payment related to acquisition of business, net of cash acquired	$ 141,900,000
Unfavorable Regulatory Action [Member]
Company And Summary Of Significant Accounting Policies [Line Items]
U.S. government contract-related reserves							$ 1,800,000	$ 2,500,000