Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Rate Reconciliation [Line Items]
Income before income taxes	$ 242,000	$ 2,255,000	$ 3,243,000	$ 5,398,000	$ 5,215,000	$ 8,143,000	$ 6,034,000	$ 3,622,000	$ 11,138,583	$ 23,013,821	$ 11,271,406
Expected tax at statutory rate									3,787,118	7,824,699	3,944,996
Adjustments due to:
Difference between U.S. and foreign tax									(1,470,662)	(1,227,747)	(8,332)
State income and franchise taxes									121,561	1,121,821	357,866
Permanent differences									(171,921)	(298,185)	242,629
Change in valuation allowance									727,157	(508,629)	(7,272,092)
Other									(24,884)	8,707	(149,698)
Provision (benefit) for income taxes	$ 640,000	$ 789,000	$ 418,000	$ 1,121,000	$ 1,887,000	$ 2,255,000	$ 1,495,000	$ 1,284,000	$ 2,968,369	$ 6,920,666	$ (2,884,631)
Expected tax at statutory rate									34.00%	34.00%	35.00%
Adjustments due to:
Difference between U.S. and foreign tax									(13.20%)	(5.30%)	(0.10%)
State income and franchise taxes									1.10%	4.90%	3.20%
Permanent differences									(1.50%)	(1.30%)	2.10%
Change in valuation allowance									6.50%	(2.21%)	(64.50%)
Other									(0.20%)	0.10%	(1.30%)
Provision (benefit) for income taxes									26.70%	30.10%	(25.60%)