COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) contract	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Operating leases
Property leased from unrelated parties with remaining terms, minimum	1 year
Property leased from unrelated parties with remaining terms, maximum	10 years
Total rent expense	$ 4,753	$ 4,904	$ 4,322
Corporate headquarters
Operating leases
Operating lease term	5 years
Operating lease renewal term	5 years
Adjacent Office Facility
Operating leases
Operating lease term	10 years
Operating lease renewal term	2 years
Operating lease term, number of additional renewal option | contract	2
Related Party
Operating leases
Total rent expense	$ 1,640	$ 1,633	$ 1,639