SHARE-BASED COMPENSATION - RSU Activity (Details) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Number of Restricted Stock Units [Roll Forward]
RSUs beginning	1,481,268
RSUs awarded	331,377
RSUs released	(434,280)
RSUs forfeited	(36,857)
RSUs ending	1,341,508
Weighted Average Purchase Price RSUs	$ 0
Weighted Average Remaining Contractual Term (Years) RSUs	1 year 4 months 24 days
Aggregate Intrinsic Value RSUs	$ 12,663,835
Number of RSUs vested and expected to vest	1,232,038
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 year 3 months 18 days
Aggregate Intrinsic Value RSUs vested and expected to vest	10,809,200
Number of RSUs exercisable	86,996
Weighted Average Purchase Price of RUSs exercisable	$ 0
Weighted Average Remaining Contractual Term (Years) of RUSs exercisable	0 years
Aggregate Intrinsic Value RSUs exercisable	821,242
Weighted average remaining recognition period in years	2 years 4 months 24 days
Unamortized compensation expense, net of estimated forfeitures	6,120,176
Other Options Disclosure [Abstract]
Intrinsic value of options exercised	1,013,000	331,000
Tax benefit from options exercised, before impact of valuation allowance	385,000	126,000
Cash received from exercise price of options exercised	$ 206,000	$ 89,000