STOCK-BASED COMPENSATION (Details) (USD $) In Thousands, except Share data, unless otherwise specified		12 Months Ended									1 Months Ended						12 Months Ended		12 Months Ended	1 Months Ended					12 Months Ended
	Dec. 31, 2012 2009 Plan	Dec. 31, 2012 Common stock options	Dec. 31, 2011 Common stock options	Dec. 31, 2010 Common stock options	Dec. 31, 2012 Common stock options Minimum	Dec. 31, 2011 Common stock options Minimum	Dec. 31, 2010 Common stock options Minimum	Dec. 31, 2012 Common stock options Maximum	Dec. 31, 2011 Common stock options Maximum	Dec. 31, 2010 Common stock options Maximum	Jan. 31, 2012 Common stock options 2009 Plan	Oct. 31, 2011 Common stock options 2009 Plan	Feb. 28, 2011 Common stock options 2009 Plan	Apr. 30, 2010 Common stock options 2009 Plan	Dec. 31, 2009 Common stock options 2009 Plan	Oct. 31, 2009 Common stock options 2009 Plan Item	Dec. 31, 2012 Common stock options 2009 Plan Item	Feb. 29, 2012 Common stock options 2009 Plan	Dec. 31, 2012 Equity-based incentive awards	Feb. 28, 2010 Equity-based incentive awards Minimum	Feb. 28, 2010 Equity-based incentive awards Maximum	Mar. 31, 2009 Former CEO Stock Options	Jan. 31, 2009 Former CEO Stock Options	Aug. 31, 2008 Former CEO Stock Options	Dec. 31, 2008 Former CEO Stock Options	Mar. 31, 2012 Former CEO Stock Options	Dec. 15, 2011 Former CEO Stock Options	Aug. 04, 2008 Former CEO Stock Options
Stock-based compensation
Maximum shares authorized for issuance	7,800,000
Percentage of options vesting on the first anniversary of the date of grant																	25.00%
Percentage of options vesting at the end of each successive three-month period following the first anniversary date of grant until the fourth anniversary of the date of grant																	6.25%
Specified successive period interval, following the first anniversary date, for vesting of additional percentage of options																	3 months
Minimum percentage of options exercisable on achievement of performance based objectives																	50.00%
Shares granted during the period											560,000	150,000	580,000	120,000	555,000	4,440,000						840,649
Exercise price of shares granted (in dollars per share)											$ 9.07	$ 11.70	$ 22.32	$ 17.45	$ 15.21	$ 16.80										$ 5.49
Number of trading days used to calculate exercise price																20 days
Number of sub-tranches into which the options are divided under Performance-based Tranche																	4
Vesting period under Time-based Tranche																								2 years	4 years
Granted (in shares)		861,873																							3,042,482
Shares granted during the period with approved performance criteria for 2012													643,125	614,375				619,375
Shares granted to Senior Executive Officers																1,000,000
Number of senior executive officers to whom shares are granted																1
Vesting rights on grant date																0.33
Vesting rights on second and third anniversaries of the grant date																0.33
Maximum contractual term																									10 years
Right to receive potential cash payments, share price (in dollars per share)																				$ 14.00	$ 16.80
Options outstanding at the end of period (in shares)		3,578,707	6,441,310																								2,364,890
Weighted average exercise price of options outstanding as at the end of the year (in dollars per share)		$ 18.58	$ 17.96																								$ 16.17
Shares granted under Time-Based Option																												1,521,241
Exercise price of shares granted under Time-Based Option (in dollars per share)																												$ 22.07
Vesting rights for shares granted under Time-Based Option, prior to proposed amendment																								0.33
Shares granted under Revenue Objective Option																							760,621
Shares granted under Cost Objective Option																							760,620
Exercise price of shares granted under Revenue Objective Option (in dollars per share)																							$ 5.49
Exercise price of shares granted Cost Objective Option (in dollars per share)																							$ 5.49
Assumptions used in the option pricing model to assess the fair values of the options granted and the fair value of equity based incentive awards
Risk free interest rate (as a percent)																			0.72%
Risk free interest rate, low end of range (as a percent)		0.38%	0.02%	1.10%
Risk free interest rate, high end of range (as a percent)		1.20%	2.37%	2.11%
Expected option life					2 years 6 months	3 months	2 years	5 years 6 months	5 years	4 years									5 years
Expected dividend yield (as a percent)					5.40%	2.87%	1.30%	6.28%	7.15%	1.50%									6.50%
Volatility factor (as a percent)																			73.54%
Volatility factor, low end of range (as a percent)		51.44%	39.37%	80.00%
Volatility factor, high end of range (as a percent)		84.69%	87.88%	81.00%
Weighted average grant-date fair value (in dollars per share)		$ 2.24	$ 7.88	$ 9.68															$ 2.061
Equity-based incentive awards vested and exercisable																			1,880,864
Liability at the end of the period																			$ 3,876
Remainder vesting period under Time-based Tranche																	3 years