Goodwill, Trade Names, and Other Identifiable Intangible Assets Acquired Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	$ 85,232	$ 68,032
Other identifiable intangible assets, accumulated amortization	38,419	34,209
Intangible assets subject to amortization, net carrying amount	46,813	33,823
Goodwill	95,096	90,647
Trade names	36,101	38,201
Intangible assets not subject to amortization, net	131,197	128,848
Database Rights
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	31,225	22,425
Other identifiable intangible assets, accumulated amortization	14,150	12,893
Intangible assets subject to amortization, net carrying amount	17,075	9,532
Customer Relationships
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	47,204	42,004
Other identifiable intangible assets, accumulated amortization	20,734	17,870
Intangible assets subject to amortization, net carrying amount	26,470	24,134
Noncompete Agreements
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	3,603	3,603
Other identifiable intangible assets, accumulated amortization	3,486	3,446
Intangible assets subject to amortization, net carrying amount	117	157
Trademarks
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	3,200	0
Other identifiable intangible assets, accumulated amortization	49	0
Intangible assets subject to amortization, net carrying amount	$ 3,151	$ 0