SHARE-BASED COMPENSATION - RSU Activity - Summary of Change (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Restricted Stock Units [Roll Forward]
RSUs beginning	1,030,486
RSUs awarded	685,113	361,000	307,000
RSUs released	(409,903)	547,000	659,000
RSUs forfeited	(47,011)
RSUs ending	1,258,685	1,030,486
Weighted Average Purchase Price RSUs	$ 0
Weighted Average Remaining Contractual Term (Years) RSUs	1 year 1 month 6 days
Aggregate Intrinsic Value RSUs	$ 15,305,610
Number of RSUs vested and expected to vest	1,196,328
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 1 month 6 days
Aggregate Intrinsic Value RSUs vested and expected to vest	13,518,577
Number of RSUs exercisable	84,603
Weighted Average Purchase Price of RUSs exercisable	$ 0
Weighted Average Remaining Contractual Term (Years) of RUSs exercisable	0 years
Aggregate Intrinsic Value RSUs exercisable	1,028,772
Weighted average remaining recognition period in years	1 year 9 months 18 days
Unamortized compensation expense, net of estimated forfeitures	$ 5,074,280