Stock Plan - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2014 Installment	Dec. 31, 2013	Dec. 31, 2012
Stock Option Plan Activity [Line Items]
Options exercisable number of installments	2
Options outstanding to purchase common stock			55,000
Options available for future grant	0	0
1993 Omnibus Stock Plan
Stock Option Plan Activity [Line Items]
Common stock shares reserved	3,000,000
Maximum exercise period of options or restricted stock granted	10 years
Maximum option exercisable term for general termination	60 days
Maximum option exercisable term for termination due to death and disability	180 days
Options exercisable number of installments	3
Options outstanding to purchase common stock	0	0
Options available for future grant	0