EQUITY STRUCTURE AND ACCOUNTS - Schedule of Treasury Stock Repurchase Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Oct. 30, 2014	Feb. 10, 2014
Class of Stock [Line Items]
Share Price				$ 17.00
Shares Repurchase Program [Roll Forward]
Purchase of treasury stock	$ (4,652)	$ (994)
Common Stock | Class A common stock
Shares Repurchase Program [Roll Forward]
Treasury Stock, Shares, Acquired	424,000	84,000
2014 Share Repurchase Authorization Program
Class of Stock [Line Items]
Percentage of Aggregate Common Stock Outstanding Under Repurchase Program	5.60%
2014 Share Repurchase Authorization Program | Class A common stock
Class of Stock [Line Items]
Authorized amount of stock repurchase			$ 50,000
Shares Repurchase Program [Roll Forward]
Authorizations remaining as of December 31, 2015	$ 49,006
Treasury Stock, Shares, Acquired	424,317
Purchase of treasury stock	$ (4,652)
Authorizations remaining as of March 31, 2016	$ 44,354	$ 49,006
2014 Share Repurchase Authorization Program | Common Stock | Class A common stock
Class of Stock [Line Items]
Share Price	$ 12.45