Segment Information - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 Segment	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Reportable segments									4
Gross profit	$ 5,657,000	$ 4,376,000	$ 4,673,000	$ 3,895,000	$ 4,892,000	$ 4,264,000	$ 3,701,000	$ 3,560,000	$ 18,601,000	$ 16,417,000	$ 13,876,000
Current Reportable Segments [Member]
Segment Reporting Information [Line Items]
Gross profit									18,601,000
Previous Reportable Segments [Member]
Segment Reporting Information [Line Items]
Gross profit										$ 16,417,000	$ 13,876,000