STOCK-BASED COMPENSATION, Stock Options (Details) (USD $)	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010 Y	Dec. 31, 2009 Y
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	$ 5.45
Upper range limit (in dollars per share)	$ 18.48
Outstanding and Exercisable [Abstract]
Number of Options Outstanding at December 31 (in shares)	1,079,223
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2.78
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 10.54
Options Outstanding, Aggregate Intrinsic Value	$ 28,217,745	[1]
Number of Options Exercisable at December 31 (in shares)	1,079,223
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	2.78
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 10.54
Options Exercisable, Aggregate Intrinsic Value	28,217,745	[1]
Exercise Price Range 1 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	$ 5.45
Upper range limit (in dollars per share)	$ 8.17
Outstanding and Exercisable [Abstract]
Number of Options Outstanding at December 31 (in shares)	386,480
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2.04
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.96
Options Outstanding, Aggregate Intrinsic Value	11,488,302	[1]
Number of Options Exercisable at December 31 (in shares)	386,480
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	2.04
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 6.96
Options Exercisable, Aggregate Intrinsic Value	11,488,302	[1]
Exercise Price Range 2 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	$ 8.18
Upper range limit (in dollars per share)	$ 12.27
Outstanding and Exercisable [Abstract]
Number of Options Outstanding at December 31 (in shares)	402,298
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	3.70
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 10.36
Options Outstanding, Aggregate Intrinsic Value	10,591,835	[1]
Number of Options Exercisable at December 31 (in shares)	402,298
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	3.70
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 10.36
Options Exercisable, Aggregate Intrinsic Value	10,591,835	[1]
Exercise Price Range 3 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range limit (in dollars per share)	$ 12.28
Upper range limit (in dollars per share)	$ 18.48
Outstanding and Exercisable [Abstract]
Number of Options Outstanding at December 31 (in shares)	290,445
Options Outstanding, Weighted Average Remaining Contractual Life (Years)	2.50
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.56
Options Outstanding, Aggregate Intrinsic Value	6,137,608	[1]
Number of Options Exercisable at December 31 (in shares)	290,445
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	2.50
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 15.56
Options Exercisable, Aggregate Intrinsic Value	6,137,608	[1]
Equity Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)	8,000,000
Number of shares available for grant (in shares)	1,534,311
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration term (in years)	10Y
Stock option activity [Roll Forward]
Outstanding at January 1 (in shares)	1,804,273
Granted (in shares)	0
Exercised (in shares)	(725,050)
Forfeited (in shares)	0
Cancelled (in shares)	0
Outstanding at December 31 (in shares)	1,079,223		1,804,273
Stock option activity, additional disclosures [Abstract]
Outstanding at January 1, Weighted average exercise price (in dollars per share)	$ 10.30
Granted, Weighted average exercise price (in dollars per share)	$ 0
Exercised, Weighted average exercise price (in dollars per share)	$ 9.94
Forfeited, Weighted average exercise price (in dollars per share)	$ 0
Cancelled, Weighted average exercise price (in dollars per share)	$ 0
Outstanding at December 31, Weighted average exercise price (in dollars per share)	$ 10.54		$ 10.30
Stock option activity, vested and expected to vest [Abstract]
Vested and expected to vest (in shares)	1,079,223
Exercisable at December 31 (in shares)	1,079,223
Vested and expected to vest, Weighted average exercise price (in dollars per share)	$ 10.54
Exercisable, Weighted average exercise price (in dollars per share)	$ 10.54
Granted, Weighted average grant date fair value (in dollars per share)			$ 3.84	$ 8.06
Assumptions used in determining fair value [Abstract]
Dividend yield rate (in hundredths)			0.00%	0.00%
Expected volatility (in hundredths)			46.30%	74.80%
Risk-free interest rate (in hundredths)			0.20%	3.60%
Expected life (in years)			0.3	10
Stock-based compensation, aggregate disclosures [Abstract]
Total intrinsic value of stock awards exercised	25,022,463		8,075,057	2,310,832
Compensation expense	0		30,497	97,145
Shares tendered to net share settle (in shares)	32,800		54,650
Value of shares tendered to net share settle	1,259,506		1,500,931
Shares withheld for tax withholding obligations (in shares)	13,031
Fair value of shares withheld for tax withholding obligations	$ 437,711

[1] The difference between the stock option's exercise price and the closing price of the common stock at December 31, 2011.