Credit Facilities and Long-Term Debt - Lines of Credit - Additional Information (Detail) (Bank of America [Member], USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Line of Credit Facility [Line Items]
Interest on amount outstanding	LIBOR plus 175 to 225 basis points
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing credit facility	$ 30,000,000
Line of credit maturity date	Apr. 01, 2017
Outstanding borrowings	23,600,000		24,500,000
Weighted average interest rate on the revolving credit facility	2.39%	2.43%
Interest expense related to line of credit	$ 145,000	$ 131,000
Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Annual commitment fee	0.25%
Changes in interest rate on amount outstanding	1.75%
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Annual commitment fee	0.45%
Changes in interest rate on amount outstanding	2.25%