GOODWILL AND OTHER INTANGIBLES - Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,232	$ 85,232
Accumulated Amortization	39,826	38,419
Intangible assets subject to amortization, net carrying amount	45,406	46,813
Goodwill	95,096	95,096
Trade names	36,101	36,101
Intangible assets not subject to amortization, net	131,197	131,197
Database Rights [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	31,225	31,225
Accumulated Amortization	14,650	14,150
Intangible assets subject to amortization, net carrying amount	16,575	17,075
Customer Relationships [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	47,204	47,204
Accumulated Amortization	21,558	20,734
Intangible assets subject to amortization, net carrying amount	25,646	26,470
Noncompete Agreements [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,603	3,603
Accumulated Amortization	3,496	3,486
Intangible assets subject to amortization, net carrying amount	107	117
Trademarks [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,200	3,200
Accumulated Amortization	122	49
Intangible assets subject to amortization, net carrying amount	$ 3,078	$ 3,151