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Share based compensation arrangement by share based payment award contractual life.

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Measurement Period

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Percentage Share Payout

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Vesting if Target Metric Achieved

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Share-based Compensation Arrangement By Share-based Payment Award, Fair Value Assumptions, Forfeiture Rate

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Share-based Compensation Arrangement by Share-based Payment Award, Options, Number of Vesting Installments

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Subsidiary equity units for which investor has right to convert to common stock.

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Amount of other increase (decrease) in additional paid in capital (APIC).

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate number of common shares reserved for future issuance.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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Amount of expense for salary, wage, profit sharing; incentive and equity-based compensation; and other employee benefit.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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The aggregate total amount of expenses directly related to the marketing or selling of products or services.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of additional shares authorized for issuance under share-based payment arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

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An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Percentage of vesting of award under share-based payment arrangement.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Value, before forfeiture, of shares issued under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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Amount of stock repurchase plan authorized.

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Amount remaining of a stock repurchase plan authorized.

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Number of shares that have been repurchased during the period and are being held in treasury.

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Period Type:

Stock Acquisition Rights, Stock Options and Warrants - Narrative (Details)															1 Months Ended		12 Months Ended
	Dec. 02, 2022 installment $ / shares shares	May 30, 2022 shares	May 18, 2022 shares	May 17, 2022 installment $ / shares shares	Sep. 07, 2021 installment $ / shares shares	Aug. 23, 2021 installment $ / shares shares	Jun. 30, 2021 shares	Feb. 01, 2021 shares	Jan. 01, 2021 shares	Dec. 30, 2020 shares	Sep. 30, 2020 USD ($) shares	Jun. 24, 2020 shares	Feb. 28, 2020 shares	Sep. 15, 2014 USD ($) $ / shares shares	May 31, 2021 USD ($) shares	May 31, 2020 USD ($) shares	Mar. 31, 2023 USD ($) $ / shares shares	Mar. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2021 USD ($) $ / shares shares	Mar. 31, 2020 $ / shares	Jun. 30, 2022 shares	Sep. 29, 2021 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General and administrative																	$ 45,177,000	$ 39,525,000	$ 39,302,000
Product development																	4,439,000	3,593,000	4,343,000
Sales and support																	5,733,000	4,461,000	2,942,000
Non-cash compensation expense attributable to stock awards																	$ 17,874,000	$ 13,625,000	$ 15,925,000
Granted (in dollars per share) \| $ / shares	$ 49.39			$ 49.39	$ 60.92	$ 57.00
Number of vesting installments \| installment	4			4	3	4
Number of shares repurchased (in shares) \| shares							20,132								20,132		216,000	252,000	0
Decrease in APIC															$ 1,000,000
Stock repurchase program, authorized amount																						$ 50,000,000
Stock repurchase program, remaining authorized repurchase amount																	$ 26,800,000
Sale of stock (in shares) \| shares		500,000	500,000
Common Class B Units \| PDV Spectrum Holding Company, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity method investee, cumulative proceeds received on all transactions														$ 10,000,000
Sale of stock (in shares) \| shares														500,000
Sale of stock (in dollars per share) \| $ / shares														$ 20.00
Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of units owned														100.00%
Shares registered for resale (in shares) \| shares																					500,000
Common Class A \| PDV Spectrum Holding Company, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Subsidiary equity units for which investor has right to convert to common stock (in shares) \| shares														500,000
President and Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares) \| shares	77,102			122,449	65,768	100,000
Executive Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares) \| shares	154,203
Lease Agreements, 900 MHz [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense																	0	$ 100,000
Stock options, contractual life																		20 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense																$ 1,500,000	10,900,000	$ 9,700,000	$ 9,200,000
General and administrative																	9,800,000	8,500,000	8,400,000
Product development																	600,000	700,000	600,000
Sales and support																	$ 500,000	500,000	200,000
Plan modification, incremental cost																			800,000
Awards issued \| shares																28,000	255,912
Unvested compensation expense																	$ 18,500,000	$ 18,400,000
Weighted average period of recognition of unrecognized compensation cost																	2 years 3 months 21 days	2 years 6 months 10 days
Awards forfeited \| shares																	17,508
Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense																			$ 0
Awards issued \| shares											91,216		95,538				0
Non-cash compensation expense attributable to stock awards											$ 4,300,000
Awards forfeited \| shares																	0		47,768
Expected term								4 years
Expected volatility rate								56.09%
Risk-free interest rate								0.29%
Dividend yield								0.00%
Forfeiture rate								0.00%
Performance-Based Restricted Stock Units \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees													50.00%
Performance-Based Restricted Stock Units \| Second Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees													50.00%
Performance-Based Restricted Stock Units \| Cumulative Spectrum Proceeds Monetized \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense																	$ 300,000	$ 300,000	$ 100,000
Unvested compensation expense																	$ 800,000	$ 800,000
Weighted average period of recognition of unrecognized compensation cost																	1 year 5 months 26 days	2 years 5 months 26 days
Measurement period												4 years
Vesting if target metric achieved (in shares) \| shares												30,049
Performance-Based Restricted Stock Units \| Cumulative Spectrum Proceeds Monetized \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage share payout																	0.00%
Performance-Based Restricted Stock Units \| Cumulative Spectrum Proceeds Monetized \| Minimum \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting if target metric achieved (in shares) \| shares												15,025
Performance-Based Restricted Stock Units \| Cumulative Spectrum Proceeds Monetized \| Maximum \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage share payout																	200.00%
Vesting if target metric achieved (in shares) \| shares												60,098
Performance-Based Restricted Stock Units \| TSR \| President and Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense																	$ 1,000,000	$ 1,000,000	$ 200,000
Unvested compensation expense																	$ 2,300,000	$ 2,300,000
Weighted average period of recognition of unrecognized compensation cost																	1 year 11 months 4 days	2 years 11 months 4 days
Vesting if target metric achieved (in shares) \| shares								45,000
Performance-Based Restricted Stock Units \| TSR \| Minimum \| President and Chief Executive Officer \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees								25.00%
Performance-Based Restricted Stock Units \| TSR \| Minimum \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage share payout																	25.00%
Performance-Based Restricted Stock Units \| TSR \| Maximum \| President and Chief Executive Officer \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees								350.00%
Performance-Based Restricted Stock Units \| TSR \| Maximum \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage share payout																	350.00%
Performance-Based Restricted Stock Units \| Additional
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards issued \| shares													43,446
Performance-Based Restricted Stock Units \| Additional \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees													100.00%
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period of recognition of unrecognized compensation cost																	1 year 8 months 4 days	1 year 5 months 19 days
Options granted (in shares) \| shares																	476,208
Granted (in dollars per share) \| $ / shares																	$ 49.39
Expected term	5 years 5 months 4 days			5 years 5 months 4 days	5 years 11 months 1 day	6 years 7 days											5 years 5 months 4 days		6 years 25 days
Expected volatility rate	50.80%			51.60%	53.45%	53.18%
Risk-free interest rate	3.62%			2.95%	0.96%	0.92%
Dividend yield	0.00%			0.00%	0.00%	0.00%											0.00%	0.00%	0.00%
Forfeiture rate	0.00%			0.00%	0.00%	0.00%												0.00%
Intrinsic value of options exercised																	$ 1,200,000	$ 29,500,000	$ 5,000,000
Weighted average grant-date fair value per option granted (in dollars per share) \| $ / shares																	$ 49.39	$ 58.56	$ 42.04
Unrecognized compensation cost related to non-vested share options granted																	$ 7,400,000	$ 4,100,000
Stock options outstanding \| shares																	1,402,949	1,006,241
Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term																	5 years 11 months 1 day
Expected volatility rate																	50.80%	53.18%	53.41%
Risk-free interest rate																	2.95%	0.92%	0.43%
Forfeiture rate																	0.00%		0.00%
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term																	6 years 7 days
Expected volatility rate																	51.60%	53.45%	52.43%
Risk-free interest rate																	3.62%	0.96%	0.51%
Forfeiture rate																	3.00%		2.00%
Service-Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense																	$ 5,600,000	$ 2,600,000	$ 1,300,000
Performance-Based Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested compensation expense																	$ 0	0
Options granted (in shares) \| shares													67,562				0
Granted (in dollars per share) \| $ / shares																	$ 0
Intrinsic value of options exercised																	$ 0	200,000	0
Weighted average grant-date fair value per option granted (in dollars per share) \| $ / shares																				$ 46.85
Stock options forfeited (in shares) \| shares										33,780
Consulting fees																	$ 0	$ 0	$ 800,000
Stock options outstanding \| shares																	33,782	33,782
Performance-Based Stock Options \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees													50.00%
Performance-Based Stock Options \| Second Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees													50.00%
Performance-Based Stock Options \| Additional
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares) \| shares													14,635
Performance-Based Stock Options \| Additional \| First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting for stock granted to employees													100.00%
2014 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized and reserved for issuance (in shares) \| shares																	5,027,201
Shares available \| shares																	502,256
Percentage of increase in number of shares of common stock issued and outstanding									5.00%								5.00%
Additional common stock authorized and reserved for future issuance (in shares) \| shares									879,216