SHARE-BASED COMPENSATION: (Details 2) (USD $)	6 Months Ended
	Sep. 30, 2013
Stock options outstanding and exercisable by exercise price range
Options outstanding (in shares)	7,141,654
Options outstanding - Weighted-average remaining contractual life	3 years 6 months 22 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 21.11
Options exercisable (in shares)	5,987,849
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 22.18
Range of exercise price per share from $6.32 to $9.62
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 6.32
Exercise price per share, high end of range (in dollars per share)	$ 9.62
Options outstanding (in shares)	48,480
Options outstanding - Weighted-average remaining contractual life	3 years 11 months 8 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 8.57
Options exercisable (in shares)	48,480
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 8.57
Range of exercise price per share from $11.08 to $15.00
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 11.08
Exercise price per share, high end of range (in dollars per share)	$ 15.00
Options outstanding (in shares)	2,070,966
Options outstanding - Weighted-average remaining contractual life	6 years 2 months 1 day
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 13.07
Options exercisable (in shares)	1,217,776
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 12.78
Range of exercise price per share from $15.10 to $19.82
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 15.10
Exercise price per share, high end of range (in dollars per share)	$ 19.82
Options outstanding (in shares)	1,134,853
Options outstanding - Weighted-average remaining contractual life	2 years 7 months 24 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 16.51
Options exercisable (in shares)	1,125,071
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 16.50
Range of exercise price per share from $20.12 to $25.00
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 20.12
Exercise price per share, high end of range (in dollars per share)	$ 25.00
Options outstanding (in shares)	2,082,859
Options outstanding - Weighted-average remaining contractual life	3 years 8 months 16 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 22.83
Options exercisable (in shares)	1,792,026
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 23.05
Range of exercise price per share from $25.98 to $29.30
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 25.98
Exercise price per share, high end of range (in dollars per share)	$ 29.30
Options outstanding (in shares)	1,010,218
Options outstanding - Weighted-average remaining contractual life	11 months 26 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 26.74
Options exercisable (in shares)	1,010,218
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 26.74
Range of exercise price per share from $30.93 to $39.12
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 30.93
Exercise price per share, high end of range (in dollars per share)	$ 39.12
Options outstanding (in shares)	616,600
Options outstanding - Weighted-average remaining contractual life	9 months 14 days
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 35.96
Options exercisable (in shares)	616,600
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 35.96
Range of exercise price per share from $40.88 to $62.06
Stock options outstanding and exercisable by exercise price range
Exercise price per share, low end of range (in dollars per share)	$ 40.88
Exercise price per share, high end of range (in dollars per share)	$ 62.06
Options outstanding (in shares)	177,678
Options outstanding - Weighted-average remaining contractual life	1 year 6 months
Options outstanding - Weighted-average exercise price per share (in dollars per share)	$ 43.74
Options exercisable (in shares)	177,678
Options exercisable - Weighted-average exercise price per share (in dollars per share)	$ 43.74