Acquired Intangible Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	$ 56,832,000	$ 42,832,000
Intangible assets subject to amortization, accumulated amortization	30,634,095	28,340,018
Intangible assets subject to amortization, net carrying amount	26,197,905	14,491,982
Goodwill	77,265,907	62,712,109
Trade names	42,301,331	48,701,331
Intangible assets not subject to amortization, net	119,567,238	111,413,440
Database Rights [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	15,925,000	12,525,000
Intangible assets subject to amortization, accumulated amortization	12,102,685	11,954,630
Intangible assets subject to amortization, net carrying amount	3,822,315	570,370
Customer Relationships [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	37,304,000	26,904,000
Intangible assets subject to amortization, accumulated amortization	15,125,076	13,089,055
Intangible assets subject to amortization, net carrying amount	22,178,924	13,814,945
Noncompete Agreements [Member]
Finite-Lived and Indefinite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross carrying amount	3,603,000	3,403,000
Intangible assets subject to amortization, accumulated amortization	3,406,334	3,296,333
Intangible assets subject to amortization, net carrying amount	$ 196,666	$ 106,667