Income Taxes - Significant Components of Company's Deferred Tax Assets and Liabilities (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Tax Assets
Net operating loss carryforwards	$ 17,314,368	$ 22,113,983
Asset basis differences - tax amount greater than book value	254,773	259,922
Liability reserves	187,253	212,142
Stock compensation plans	1,644,339	1,520,041
AMT credit carryforwards	1,576,737	1,273,792
Other	45,903	21,585
Deferred tax assets, gross	21,023,373	25,401,465
Valuation allowance	0	0	$ 0
Total deferred tax assets	21,023,373	25,401,465
Deferred Tax Liabilities
Acquired asset differences - book value greater than tax	(2,266,160)	(2,669,655)
Asset basis differences - carrying amount value greater than tax	(327,476)	(295,073)
Total deferred tax liabilities	(2,593,636)	(2,964,728)
Net deferred tax asset (liability)	$ 18,429,737	$ 22,436,737