STOCK-BASED COMPENSATION Stock Option Activity (Details) (Stock Options [Member], USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at March 31, 2012	3,304
Options granted	200
Options exercised	(63)
Options forfeited or expired	(97)
Options outstanding at June 30, 2012	3,344
Weighted average exercise price of options outstanding, March 31, 2012	$ 26.47
Weighted average exercise price of options granted	$ 33.27
Weighted average exercise price of options exercised	$ 20.83
Weighted average exercise price of options forfeited or expired	$ 34.76
Weighted average exercise price of options outstanding, June 30, 2012	$ 26.75
Weighted average remaining contractual life of options outstanding at June 30, 2012	3 years 256 days
Aggregate intrinsic value of options outstanding at June 30, 2012	$ 24,187,000
Vested and expected to vest at June 30, 2012	3,303
Weighted average exercise price of options vested and expected to vest at June 30, 2012	$ 26.66
Weighted average remaining contractual life of options vested and expected to vest at June 30, 2012	3 years 219 days
Aggregate intrinsic value of options vested and expected to vest at June 30, 2012	24,148,000
Exercisable at June 30, 2012	2,427
Weighted average exercise price of options exercisable at June 30, 2012	$ 24.26
Weighted average remaining contractual life of options exercisable at June 30, 2012	2 years 292 days
Aggregate intrinsic value of options exercisable at June 30, 2012	22,900,000
Total intrinsic value of options exercised	800,000	9,100,000
Total cash received as a result of stock option exercises	1,300,000
Total unrecognized compensation cost related to unvested stock options	$ 9,700,000
Period of recognition for unrecognized compensation cost related to unvested stock options	2 years