GOODWILL AND OTHER INTANGIBLES - Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 79,240	$ 85,232
Accumulated Amortization	41,232	38,419
Intangible assets subject to amortization, net carrying amount	38,008	46,813
Goodwill	77,376	95,096
Trade names	35,502	36,101
Intangible assets not subject to amortization, net	112,878	131,197
Database [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	31,225	31,225
Accumulated Amortization	15,148	14,150
Intangible assets subject to amortization, net carrying amount	16,077	17,075
Customer Relationships [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	41,212	47,204
Accumulated Amortization	22,382	20,734
Intangible assets subject to amortization, net carrying amount	18,830	26,470
Noncompete Agreements [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,603	3,603
Accumulated Amortization	3,506	3,486
Intangible assets subject to amortization, net carrying amount	97	117
Trade names, definite lived [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,200	3,200
Accumulated Amortization	196	49
Intangible assets subject to amortization, net carrying amount	$ 3,004	$ 3,151