Share-Based Compensation - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Document Period End Date	Jun. 30, 2014
Granted awards, shares	806
Awards to non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization of expense equally over a service period	1 year
Unrecognized compensation expense related to the awards to non-employee directors	$ 458,000
Granted awards, shares	8,866
Award to key employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted awards, shares	27,628
Intrinsic value of the SICP awards	$ 5,900,000
2014-2016 service period [Member] | Award to key employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted awards, shares	23,200
Vesting period	3 years
2013-2015 service period [Member] | Award to key employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted awards, shares	4,428
Vesting period	3 years