GOODWILL AND OTHER INTANGIBLES - Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 79,240	$ 85,232
Accumulated Amortization	42,279	38,419
Intangible assets subject to amortization, net carrying amount	36,961	46,813
Goodwill	77,376	95,096
Trade names	35,452	36,101
Intangible assets not subject to amortization, net	112,828	131,197
Database [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	31,225	31,225
Accumulated Amortization	15,646	14,150
Intangible assets subject to amortization, net carrying amount	15,579	17,075
Customer Relationships [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	41,212	47,204
Accumulated Amortization	22,848	20,734
Intangible assets subject to amortization, net carrying amount	18,364	26,470
Noncompete Agreements [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,603	3,603
Accumulated Amortization	3,516	3,486
Intangible assets subject to amortization, net carrying amount	87	117
Trade names, definite lived [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,200	3,200
Accumulated Amortization	269	49
Intangible assets subject to amortization, net carrying amount	$ 2,931	$ 3,151