STOCK COMPENSATION PLANS (Details 4) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restricted Stock Awards \| Minimum
Summary of Stock-based Compensation Plans
Vesting period	1 year
Restricted Stock Awards \| Maximum
Summary of Stock-based Compensation Plans
Vesting period	5 years
Time-based restricted stock awards
Summary of restricted stock awards activity
Outstanding unvested at beginning of period (in shares)	1,812,890
Granted (in shares)	47,214
Vested (in shares)	(157,074)
Forfeited (in shares)	(190,634)
Outstanding unvested at end of period (in shares)	1,512,396	1,812,890
Outstanding unvested at beginning of period, weighted average price (in dollars per share)	$ 16.79
Granted, weighted average price (in dollars per share)	$ 21.66	$ 19.17	$ 17.11
Vested, weighted average price (in dollars per share)	$ 22.51
Forfeited, weighted average price (in dollars per share)	$ 17.46
Outstanding unvested at end of period, weighted average price (in dollars per share)	$ 16.30	$ 16.79
Total fair value of restricted stock awards vested	$ 3,500,000	$ 4,900,000	$ 4,300,000
Total unrecognized stock compensation expense	7,900,000
Weighted average period to recognize unrecognized compensation cost	1 year 7 months 20 days
Performance-based restricted stock awards
Summary of restricted stock awards activity
Outstanding unvested at beginning of period (in shares)	480,735
Granted (in shares)	465,175
Vested (in shares)	(217,906)
Forfeited (in shares)	(33,166)
Outstanding unvested at end of period (in shares)	694,838	480,735
Outstanding unvested at beginning of period, weighted average price (in dollars per share)	$ 22.19
Granted, weighted average price (in dollars per share)	$ 22.05	$ 22.25
Vested, weighted average price (in dollars per share)	$ 21.08
Forfeited, weighted average price (in dollars per share)	$ 22.55
Outstanding unvested at end of period, weighted average price (in dollars per share)	$ 22.43	$ 22.19
Total fair value of restricted stock awards vested	4,700,000
Total unrecognized stock compensation expense	$ 10,500,000
Weighted average period to recognize unrecognized compensation cost	1 year 10 months 17 days

As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The total fair value of equity-based awards for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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