Operating Leases - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leases Future Minimum Payments Due [Line Items]
Rent expense total	$ 934,223	$ 882,215	$ 934,206
Minimum [Member]
Operating Leases Future Minimum Payments Due [Line Items]
Lease expiration date	Dec. 31, 2015
Maximum [Member]
Operating Leases Future Minimum Payments Due [Line Items]
Lease expiration date	Dec. 31, 2024