Post-retirement Life Insurance Benefit - Additional Information (Detail) (USD $)	1 Months Ended	6 Months Ended
	Jun. 30, 2012 Age	Jun. 30, 2013 Age
Compensation And Retirement Disclosure [Abstract]
Postretirement life insurance benefit amount	$ 50,000	$ 50,000
Annual decrease in postretirement life insurance benefit	5,000	5,000
Minimum benefit under post-retirement life insurance	5,000	5,000
Age limit for postretirement life insurance benefit	75	75
One-time payment to the insurance company		4,100,000
Settlement charge, net of tax		$ 1,600,000