EARNINGS PER COMMON SHARE - Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Share data	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Numerator for basic and diluted earnings per share -income available to common shareholders:
Net income	$ 15,618	$ 15,579	$ 48,798	$ 44,951
Dividends on preferred stock	0	0	0	1,865
Income available to common shareholders	$ 15,618	$ 15,579	$ 48,798	$ 43,086
Denominator for basic earnings per share - weighted average shares	57,735,811	57,570,709	57,674,250	56,765,933
Effect of dilutive securities -
Employee stock awards	841,604	873,959	930,461	887,478
Warrants	76,684	86,837	95,241	105,495
Denominator for diluted earnings per share - adjusted weighted average shares	58,654,099	58,531,505	58,699,952	57,758,906
Earnings per share available to common shareholders
Basic	$ 0.27	$ 0.27	$ 0.85	$ 0.76
Diluted	$ 0.27	$ 0.27	$ 0.83	$ 0.75

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Net Income (Loss) Available to Common Stockholders, Basic and Diluted [Abstract]

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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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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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