Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2019
Cash flows from operating activities:
Net income (loss)	$ 10,590		$ (10,737)	$ 8,915	$ (71,832)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation				207,950	195,562
Amortization of intangible assets				47,159	42,543
Stock-based compensation expense	21,900		20,200	64,236	58,658
Loss on disposition of fixed assets				33,578	38,374
Other non-cash adjustments				(9,394)	(27,908)
Increase (decrease) in cash resulting from changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable				(23,596)	(38,909)
Inventories				(47,897)	(32,250)
Other assets				4,075	(15,430)
Accounts payable				8,384	4,234
Accrued liabilities				16,596	52,534
Other liabilities				(16,644)	9,085
Net cash provided by operating activities				293,362	214,661
Cash flows from investing activities:
Purchase of property, equipment and satellites				(548,225)	(491,839)
Cash paid for patents, licenses and other assets				(49,613)	(32,500)
Proceeds from insurance claims on ViaSat-2 satellite		$ 2,300		2,277	172,206	$ 185,700
Proceeds from sale of real property					14,034
Payments related to acquisition of business, net of cash acquired					(2,339)
Net cash used in investing activities				(595,561)	(340,438)
Cash flows from financing activities:
Proceeds from debt borrowings				110,000	465,000
Payments of debt borrowings				(27,142)	(350,115)
Payment of debt issuance costs				(2,479)
Proceeds from issuance of common stock under equity plans				38,093	23,595
Purchase of common stock in treasury (immediately retired) related to tax withholdings for stock-based compensation				(28,268)	(28,108)
Other financing activities				(1,746)	(9,735)
Net cash provided by financing activities				88,458	100,637
Effect of exchange rate changes on cash				(182)	(2,941)
Net decrease in cash and cash equivalents				(213,923)	(28,081)
Cash and cash equivalents at beginning of period		$ 261,701		261,701	71,446	71,446
Cash and cash equivalents at end of period	$ 47,778		$ 43,365	47,778	43,365	$ 261,701
Non-cash investing and financing activities:
Issuance of common stock in satisfaction of certain accrued employee compensation liabilities				22,829	32,129
Capital expenditures not paid for				$ 24,460	$ 34,237