EQUITY COMPENSATION PLANS AND SHARE-BASED COMPENSATION, Restricted Stock Units (Details) (USD $)		6 Months Ended				3 Months Ended		6 Months Ended								12 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 Target/Service Condition One [Member]	Sep. 30, 2013 Target/Service Condition Two [Member]	Sep. 30, 2013 Target/Service Condition Three [Member]	Sep. 30, 2013 Target/Service Condition Four [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2012 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2013 Time-Based Restricted Stock Units [Member]		Sep. 30, 2013 Time-Based Restricted Stock Units [Member] Employees [Member]	Sep. 30, 2013 Time-Based Restricted Stock Units [Member] Non-Employee Directors [Member]	Sep. 30, 2013 Performance RSUs [Member]		Mar. 31, 2013 FY 2013 Performance RSUs [Member]	Sep. 30, 2013 FY 2013 Performance RSUs [Member]	Sep. 30, 2013 FY 2014 Performance RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Time-based vesting schedules												Four-year time-based vesting as follows: five percent vesting after the first year; additional ten percent after the second year; additional 15 percent after the third year; and the remaining 70 percent after the fourth year of continuous employment with the Company.	100 percent vesting after one year of continuous service to the Company.
Vesting percentage after first year (in hundredths)												5.00%	100.00%
Additional vesting percentage after second year (in hundredths)												10.00%
Additional vesting percentage after third year (in hundredths)												15.00%
Additional vesting percentage after fourth year (in hundredths)												70.00%
Shares not probable to vest (in shares)																		129,000
Unrecognized compensation expense	$ 0									$ 21,300,000							$ 0
Weighted average service period for recognition of unrecognized compensation costs										1 year 10 months 24 days
Maximum shares authorized for issuance (in shares)																84,000		129,000
Aggregate estimated grant date fair value																752,000		5,500,000
Aggregate estimated grant date fair value (in dollars per share)																$ 35.62		$ 42.43
Number of performance period																4
Percentage of restricted stock unit awards deemed granted each year																25.00%
Percentage of restricted stock unit awards approved, but deemed not granted																75.00%
Performance target of restricted stock units by vesting date [Abstract]
Shares Issuable Upon Settlement of FY2014 Performance RSUs (in hundredths)		0.25	0.25	0.25	0.25
Consolidated Income from Operations for the Year Ending March 31, 2014		> 90% of target	> 90% of target	>100% of target	> 100% of target
Vesting Date		Apr. 29, 2016	Apr. 29, 2017	Apr. 29, 2016	Apr. 29, 2017
Restricted Stock Unit Activity [Roll Forward]
Nonvested, beginning of period (in shares)										980,000				21,000	[1]
Granted (in shares)										161,000				129,000	[1]
Vested (in shares)										(285,000)	[2]			(21,000)	[1],[2]
Canceled or forfeited (in shares)										(11,000)				0	[1]
Nonvested, end of period (in shares)										845,000				129,000	[1]
Restricted Stock Units Activity (in dollars per share) [Roll Forward]
Nonvested, beginning of period (in dollars per share)										$ 26.42	[3]			$ 35.62	[3]
Granted (in dollars per share)										$ 41.80	[3]			$ 42.43	[3]
Vested (in dollars per share)										$ 21.54	[2],[3]			$ 35.62	[2],[3]
Canceled or forfeited (in dollars per share)										$ 30.65	[3]			$ 0	[3]
Nonvested, end of period (in dollars per share)										$ 30.95	[3]			$ 42.43	[3]
Additional share based compensation that would have been recorded if performance targets had been deemed probable																		676,000
Total intrinsic value						2,400,000	1,800,000	12,900,000	8,700,000
Total grant date fair value						$ 1,500,000	$ 1,100,000	$ 6,900,000	$ 5,800,000

[1] Nonvested shares at March 31, 2013 include only the FY2013 Performance RSUs that were deemed granted in accordance with ASC 718-10-55-95.

[2] The number of restricted stock units vested includes shares that we withheld on behalf of our employees to satisfy the statutory tax withholding requirements.

[3] The weighted average grant date fair value of restricted stock units is based on the number of shares and the closing market price of our common stock on the date of grant.