Subsequent Events (Details)	12 Months Ended
	Mar. 31, 2019	Apr. 29, 2018 $ / shares	Apr. 25, 2018	Mar. 31, 2018 $ / shares	Mar. 31, 2017 $ / shares
Subsequent Event [Line Items]
Common stock, par value				$ 0.01	$ 0.01
Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock, par value		$ 0.01
Exchange Ratio		0.10256
Fully diluted shares, percentage owned		31.00%
Contract Termination Claims, Description	600
Deutsche Telekom [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Fully diluted shares, percentage owned		42.00%	63.50%
SoftBank [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Fully diluted shares, percentage owned		27.00%	84.85%
T-Mobile [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock, par value		$ 0.00001
GALAXY [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock, par value		0.01
Starburst [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock, par value		$ 0.01