SHARE-BASED COMPENSATION - RSU Activity (Details) (USD $)	6 Months Ended
	Jun. 30, 2012 number	Jun. 30, 2011
Number of Restricted Stock Units [Roll Forward]
RSUs beginning	1,860,577
RSUs awarded	288,056
RSUs released	(329,755)
RSUs forfeited	(13,014)
RSUs ending	1,805,864
Weighted Average Purchase Price RSUs	$ 0
Weighted Average Remaining Contractual Term (Years) RSUs	1.5
Aggregate Intrinsic Value RSUs	$ 10,871,301
Number of RSUs vested and expected to vest	1,659,512
Weighted Average Purchase Price of RSUs vested and expected to vest	$ 0
Weighted Average Remaining Contractual Term (Years) of RUSs vested and expected to vest	1.4
Aggregate Intrinsic Value RSUs vested and expected to vest	9,466,549
Number of RSUs exercisable	86,996
Weighted Average Purchase Price of RUSs exercisable	$ 0
Weighted Average Remaining Contractual Term (Years) of RUSs exercisable	0.0
Aggregate Intrinsic Value RSUs exercisable	523,716
Weighted average remaining recognition period in years	2.1
Unamortized compensation expense, net of estimated forfeitures	7,854,915
Other Options Disclosure [Abstract]
Intrinsic value of options exercised	331,000	512,000
Tax benefit from options exercised, before impact of valuation allowance	126,000	195,000
Cash received from exercise price of options exercised	$ 89,000	$ 66,000