Stock Plans - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of options outstanding (in years)	10 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for grants (in years)	3 years
Actual shares earned, possible percentage on target award	50.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for grants (in years)	4 years
Actual shares earned, possible percentage on target award	150.00%
Total Shareholder Return [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for grants (in years)	3 years