Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization expense for intangible assets	$ 1,280,000	$ 1,209,000	$ 2,500,625	$ 2,362,409
Database [Member]
Finite-Lived Intangible Assets [Line Items]
Amount capitalized to intangible asset	718,000	562,000	1,314,000	1,158,000
Amortization expense for intangible assets	507,000	439,000	989,000	852,000
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense for intangible assets	238,000	241,000	476,000	482,000
Website [Member]
Finite-Lived Intangible Assets [Line Items]
Amount capitalized to intangible asset	525,000	410,000	1,011,000	892,000
Amortization expense for intangible assets	459,000	453,000	884,000	876,000
Acquired Below Market Lease [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense for intangible assets	$ 76,000	$ 76,000	$ 152,000	$ 152,000