Goodwill, Trade Names, and Other Intangible Assets - Acquired Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	$ 80,168	$ 85,232
Other identifiable intangible assets, accumulated amortization	43,333	38,419
Intangible assets subject to amortization, net carrying amount	36,835	46,813
Trade names	35,402	36,101
Intangible assets not subject to amortization, net	72,237	82,914
Database Rights
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	31,609	31,225
Other identifiable intangible assets, accumulated amortization	16,147	14,150
Intangible assets subject to amortization, net carrying amount	15,462	17,075
Customer Relationships
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	41,724	47,204
Other identifiable intangible assets, accumulated amortization	23,316	20,734
Intangible assets subject to amortization, net carrying amount	18,408	26,470
Noncompete Agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	3,619	3,603
Other identifiable intangible assets, accumulated amortization	3,527	3,486
Intangible assets subject to amortization, net carrying amount	92	117
Trade Names
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	3,216	3,200
Other identifiable intangible assets, accumulated amortization	343	49
Intangible assets subject to amortization, net carrying amount	$ 2,873	$ 3,151