Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended				6 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2026	Oct. 31, 2025	Mar. 31, 2026	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2025	Dec. 31, 2025	Dec. 31, 2024	Mar. 31, 2026	Mar. 31, 2025
Loss Contingencies [Line Items]
Revenues				$ 1,157,045		$ 1,123,767		$ 3,468,992	$ 3,372,489
Deferred revenues, long-term portion				1,078,238				1,078,238			$ 786,710
Interest income				165,590		17,708		192,405	64,396
Ligado [Member]
Loss Contingencies [Line Items]
Revenues				16,000	$ 16,000
Ligado [Member] | Forecast [Member]
Loss Contingencies [Line Items]
Revenues			$ 16,000
Inmarsat [Member]
Loss Contingencies [Line Items]
Contingent legal settlement escalator							3.00%
Inmarsat [Member] | Forecast [Member]
Loss Contingencies [Line Items]
Contingent proceeds from legal settlements	$ 100,000
Contingent and actual proceeds from legal settlements										$ 568,000
Lump Sum | Ligado [Member]
Loss Contingencies [Line Items]
Proceeds from legal settlement		$ 420,000
Deferred revenues, long-term portion		$ 267,500
Interest income				152,500
Product [Member]
Loss Contingencies [Line Items]
Revenues				334,227		314,397		998,294	944,084
Service [Member]
Loss Contingencies [Line Items]
Revenues				822,818		809,370		2,470,698	$ 2,428,405
Defense and Advanced Technologies [Member] | Positive Outcome Of Litigation [Member] | Product [Member]
Loss Contingencies [Line Items]
Revenues				30,800		$ 41,700
Unfavorable Regulatory Action [Member]
Loss Contingencies [Line Items]
U.S. government contract-related reserves				$ 15,100				$ 15,100			$ 14,800