- STOCK ACTIVITY (Details) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Shares
Non-vested restricted stock units at the beginning of the year (in shares)	1,133,000
Vested (in shares)	(591,912)
Forfeited (in shares)	(27,578)
Non-vested restricted stock units at the end of the year (in shares)	0	1,133,000
Restricted stock
Shares
Non-vested restricted stock units at the beginning of the year (in shares)	6,405,000
Granted (in shares)	1,161,000
Vested (in shares)	(3,220,000)
Forfeited (in shares)	(87,000)
Non-vested restricted stock units at the end of the year (in shares)	4,259,000	6,405,000
Weighted Average Fair Value on Grant Date
Non-vested restricted stock at the beginning of the year (in dollars per share)	$ 24.74
Granted (in dollars per share)	47.48
Vested (in dollars per share)	23.54
Forfeited (in dollars per share)	20.76
Non-vested restricted stock at the end of the year (in dollars per share)	$ 32.93	$ 24.74
Employee Market-Based
Weighted-average assumptions
Risk-free interest rate	0.90%	0.60%	0.40%
Expected stock price volatility	31.20%	33.90%	31.90%
Expected service period (years)	1 year 6 months	1 year 10 months 24 days	2 years
Dividends	$ 0	$ 0	$ 0
Non-Employee Market-Based
Weighted-average assumptions
Risk-free interest rate	0.70%	0.40%	0.10%
Expected stock price volatility	30.10%	32.20%	33.70%
Expected service period (years)	1 year	1 year 1 month 6 days	3 years 8 months 12 days
Dividends	$ 0	$ 0	$ 0