Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation Related Costs [Abstract]
Severance costs	$ 866,000	$ 881,000	$ 961,000
Deferred compensation agreements expenses	544,000	561,000	494,000
Maximum percentage of salary defer by individual under deferred compensation plan	75.00%
Maximum percentage of bonus defer by individual under deferred compensation plan	100.00%
Deferred compensation plan, discretionary payments	0	0	0
Amounts paid under deferred compensation and salary continuation agreements	2,100,000
Employer contribution percentage to 401(k) plan	3.00%
Employer contribution in profit-sharing plan	$ 3,100,000	$ 2,700,000	$ 2,400,000