Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Taxes [Line Items]
Income tax expense	$ 3,467,219	$ 2,347,873	$ 5,371,083	$ 3,447,611
Effective income tax rate	37.00%	38.60%	37.50%	37.90%
Federal | Minimum
Income Taxes [Line Items]
Tax years subject to examination			2009
Federal | Maximum
Income Taxes [Line Items]
Tax years subject to examination			2012
State | Minimum
Income Taxes [Line Items]
Tax years subject to examination			2009
State | Maximum
Income Taxes [Line Items]
Tax years subject to examination			2012
Italy | Minimum
Income Taxes [Line Items]
Tax years subject to examination			2009
Italy | Maximum
Income Taxes [Line Items]
Tax years subject to examination			2012