DESCRIPTION OF BUSINESS (Details) - USD ($)		1 Months Ended					12 Months Ended
	Mar. 24, 2015	Mar. 31, 2015	Jan. 31, 2014	Aug. 31, 2013	Feb. 28, 2013	Jan. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Subsidiary, Sale of Stock [Line Items]
Price per common share (in dollars per share)		$ 19.00	$ 8.50	$ 4.50	$ 3.00	$ 3.00
Net proceeds from the offering							$ 149,487,000	$ 40,000,000	$ 30,937,000
Underwriting fees and other offering costs		$ 9,000,000	$ 3,200,000	$ 2,800,000	$ 900,000	$ 0
Common Stock | Public Offering
Subsidiary, Sale of Stock [Line Items]
Number of common stock issued	7,866,000
Price per common share (in dollars per share)	$ 19.00
Net proceeds from the offering	$ 140,000,000
Underwriting fees and other offering costs	$ 9,500,000