NET INCOME PER COMMON SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Impact Of Equity Awards [Line Items]
Excluded shares as anti-dilutive when reporting loss	913	0	1,025	0
Earnings Per Share, Basic and Diluted [Abstract]
Net Income (Loss) Attributable to Parent	$ (3,207)	$ 48,734	$ (4,256)	$ 49,755	$ 68,510
Weighted Average Number Of Shares Outstanding Basic	36,685,635	36,352,750	36,668,347	36,337,899
Earnings Per Share Basic	$ (0.09)	$ 1.34	$ (0.12)	$ 1.37
Incremental Common Shares Attributable to Share-based Payment Arrangements	0	1,388,839	0	1,616,697
Weighted Average Number Of Diluted Shares Outstanding	36,685,635	37,741,589	36,668,347	37,954,596
Earnings Per Share Diluted	$ (0.09)	$ 1.29	$ (0.12)	$ 1.31
Options Activity [Member]
Impact Of Equity Awards [Line Items]
Excluded shares as anti-dilutive under the treasury stock method	50	54	53	54
Price range of option: from	$ 5.56	$ 9.39	$ 6.36	$ 10.22
Price range of option: to	$ 48.21	$ 48.21	$ 48.21	$ 48.21
Restricted Stock Units Activity [Member]
Impact Of Equity Awards [Line Items]
Excluded shares as anti-dilutive under the treasury stock method	1,418	1,253	1,281	872
Restricted Stock Units Activity [Member] | Restricted Stock Units Service Conditions [Member]
Impact Of Equity Awards [Line Items]
Excluded shares as anti-dilutive under the treasury stock method	1,218	1,053	1,081	672
Restricted Stock Units Activity [Member] | Restricted Stock Units Service And Market Conditions But Market Not Met [Member]
Impact Of Equity Awards [Line Items]
Excluded shares as anti-dilutive under the treasury stock method	200	200	200	200