EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
EARNINGS PER SHARE
Net income	$ 137,309	$ 13,478
Weighted average shares outstanding - basic	41,816,000	41,631,000
Dilutive effect of Treasury warrants (in shares)	29,000	21,000
Weighted average shares outstanding - diluted	42,297,000	41,839,000
Basic earnings per share (in dollars per share)	$ 3.28	$ 0.32
Diluted earnings per share (in dollars per share)	$ 3.25	$ 0.32
Antidilutive securities excluded from the dilutive share calculation (in shares)	26,256	40,166
Employee stock options and awards
SHARE-BASED COMPENSATION
Dilutive effect of share-based compensation arrangements	447,000	127,000
Deferred salary restricted stock units
SHARE-BASED COMPENSATION
Dilutive effect of share-based compensation arrangements	5,000	60,000

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