EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
EARNINGS PER SHARE
Authorized common stock (in shares)	199,000,000us-gaap_CommonStockSharesAuthorized		199,000,000us-gaap_CommonStockSharesAuthorized
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Diluted
Income available to common stockholders (in dollars)	$ 45,171	$ 48,389
Shares of common stock	62,292,000	65,468,000
Total average equivalent shares	64,494,000	68,232,000
Net income per share, diluted (in dollars per share)	$ 0.70us-gaap_EarningsPerShareDiluted	$ 0.71us-gaap_EarningsPerShareDiluted
Basic
Income available to common stockholders (in dollars)	$ 45,171	$ 48,389
Shares of common stock	62,292,000	65,468,000
Net income per share, basic (in dollars per share)	$ 0.73us-gaap_EarningsPerShareBasic	$ 0.74us-gaap_EarningsPerShareBasic
Stock options
Diluted
Effect of dilutive stock based compensation (in shares)	2,182,000	2,738,000
Restricted stock units
Diluted
Effect of dilutive stock based compensation (in shares)	20,000	26,000

Face amount or stated value per share of common stock.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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