Stock Based Compensation - Additional Information (Detail) (Restricted Units, USD $)	1 Months Ended	3 Months Ended		1 Months Ended	9 Months Ended		1 Months Ended
	Jan. 30, 2013	Sep. 30, 2013 Long Term Incentive Plan	Sep. 30, 2012 Long Term Incentive Plan	Jan. 30, 2013 Board of Directors Chairman	Sep. 30, 2013 Board of Directors Chairman Long Term Incentive Plan	Sep. 30, 2012 Board of Directors Chairman Long Term Incentive Plan	Jan. 30, 2013 Board of Directors Chairman Third anniversary	Jan. 30, 2013 Board of Directors Chairman Fourth anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity compensation units, granted in period	30,200			6,000
Vesting period of restricted stock unit award	4 years
Equity Compensation expense		$ 225,000	$ 110,000		$ 988,000	$ 629,000
Award vesting percentage							50.00%	50.00%