FAIR VALUE (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquisitions
Impairment of Long-Lived Assets Held-for-use	$ 4,100,000	$ 0	$ 0
Business Combination, Contingent Consideration Arrangement - Equator	(7,591,000)	(37,924,000)	0
Goodwill impairment	55,740,000	37,473,000
Impairment of intangible assets	11,900,000		0
Cash and cash equivalents	179,327,000	161,361,000	$ 130,324,000	$ 105,502,000
Restricted cash	4,801,000	3,022,000
Equator LLC
Acquisitions
Payment made to extinguish Equator contingent consideration	500,000
Value of Equator contingent consideration after payment to sellers	0
Goodwill impairment		37,500,000
Fair value measurements
Acquisitions
Fair values of the liabilities for acquisition-related contingent consideration	3,900,000	11,600,000
Long-term Debt, Gross	536,598,000	591,543,000
Fair Value, Inputs, Level 1 [Member] | Fair value measurements
Acquisitions
Cash and cash equivalents	179,327,000	161,361,000
Restricted cash	4,801,000	3,022,000
Long-term debt	0	0
Fair Value, Inputs, Level 2 [Member] | Fair value measurements
Acquisitions
Cash and cash equivalents	0	0
Restricted cash	0	0
Long-term debt	469,523,000	467,319,000
Fair Value, Inputs, Level 3 [Member] | Fair value measurements
Acquisitions
Cash and cash equivalents	0	0
Restricted cash	0	0
Long-term debt	$ 0	$ 0