Stock-Based Compensation - Additional Information 1 (Detail) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	0 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 2013 Long Term Incentive Plan [Member] Restricted Stock Units (RSUs) [Member]	Sep. 30, 2013 2013 Long Term Incentive Plan [Member] Restricted Stock Units (RSUs) [Member]	May 09, 2013 Incentive Stock Plan (2008 Plan) [Member] Director Restricted Stock [Member]	Sep. 30, 2013 Incentive Stock Plan (2008 Plan) [Member] Director Restricted Stock [Member]	Sep. 30, 2013 Incentive Stock Plan (2008 Plan) [Member] Director Restricted Stock [Member]
Stock Based Compensation [Line Items]
Grant date					Mar. 05, 2013	Mar. 05, 2013		May 09, 2013	May 09, 2013
Weighted average price of restricted stock					$ 19.17				$ 20.60
Stock-based compensation cost, gross	$ 114,000	$ 165,000	$ 446,000	$ 909,000	$ 31,000	$ 74,000		$ 77,000	$ 122,000
Total unrecognized compensation cost related to restricted stock units					$ 292,000	$ 292,000		$ 187,000	$ 187,000
Maximum number of achievable RSUs					28,000	28,000
Number of restricted shares awarded to each director							3,000
Vesting period for share-based awards issued							1 year