Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Benefit Plans [Line Items]
Aggregate expense under employee benefit plan	$ 1,160,000	$ 839,000	$ 571,000
Profit Sharing Plan [Member]
Employee Benefit Plans [Line Items]
Participant service term to meet the eligibility requirements	12 months
Minimum hours need to be worked by employees	1000 hours
Minimum age of participant	21 years