Property and Equipment - Property and Equipment (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 21,463,856	$ 20,943,795
Accumulated depreciation	(14,183,441)	(14,275,306)
Property and equipment, Net	7,280,415	6,668,489
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	9,918,045	9,129,318
Automobiles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 779,357	1,334,385
Lease office equipment and automobiles range	5 years
Real Estate [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 7,971,590	7,685,228
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 2,794,864	$ 2,794,864
Lease office equipment and automobiles range	5 years
Minimum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	3 years
Minimum [Member] | Real Estate [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	5 years
Maximum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	15 years
Maximum [Member] | Real Estate [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	50 years