EARNINGS (LOSS) PER SHARE ("EPS") (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Computation of Basic EPS:
Net income (loss)	$ 578,426	$ 71,365	$ 392,392	$ (51,964)
Less: net income allocated to participating securities	(77,857)	(5,808)	(42,482)
Net income (loss) for basic EPS calculation	500,569	65,557	349,910	(51,964)
Total weighted average shares outstanding - basic	98,290,000	93,338,000	97,529,000	85,382,000
Less: weighted average participating shares outstanding	(13,230,000)	(7,596,000)	(10,559,000)
Weighted average common shares outstanding - basic	85,060,000	85,742,000	86,970,000	85,382,000
Basic EPS (in dollars per share)	$ 5.88	$ 0.76	$ 4.02	$ (0.61)
Computation of Diluted EPS:
Net income (loss)	578,426	71,365	392,392	(51,964)
Less: net income allocated to participating securities	(61,200)	(5,808)	(32,412)
Add: interest expense, net of tax, on Convertible Notes	7,418	7,834	26,221
Net income (loss) for diluted EPS calculation	$ 524,644	$ 73,391	$ 386,201	$ (51,964)
Weighted average shares outstanding - basic	85,060,000	85,742,000	86,970,000	85,382,000
Add: dilutive effect of common stock equivalents (in shares)	26,752,000	26,021,000	30,304,000
Weighted average common shares outstanding - diluted	111,812,000	111,763,000	117,274,000	85,382,000
Diluted EPS (in dollars per share)	$ 4.69	$ 0.66	$ 3.29	$ (0.61)
Antidilutive shares
Common stock issued in connection with restricted stock awards (in shares)	238,000		8,010,000
Unvested restricted stock awards, canceled (in shares)	58,000		161,000
Unvested restricted stock
Antidilutive shares
Antidilutive shares excluded from calculation of EPS				7,754,000
4.375% convertible notes due 2014 ("4.375% Convertible Notes")
Antidilutive shares
Issuance of convertible notes, interest rate (as a percent)	4.375%		4.375%
Stock option awards
Antidilutive shares
Antidilutive shares excluded from calculation of EPS		2,009,000		2,009,000