Summary of Information about Restricted Stock Grants Outstanding (Detail)	9 Months Ended
	Sep. 30, 2014
November 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	443,250
Estimated Forfeiture Rate	8.40%
Vesting Schedule	3 equal annual installments commencing on October 20, 2012
November 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	494,151
Estimated Forfeiture Rate	8.20%
Vesting Schedule	3 equal annual installments commencing on October 20, 2013
August 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	100,000
Estimated Forfeiture Rate	8.20%
Vesting Schedule	3 equal annual installments commencing on October 20, 2014
November 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	470,997
Estimated Forfeiture Rate	8.20%
Vesting Schedule	3 equal annual installments commencing on October 20, 2014
January 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	4,100
Estimated Forfeiture Rate	8.20%
Vesting Schedule	3 equal annual installments commencing on October 20, 2014
March 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	18,802
Estimated Forfeiture Rate	8.20%
Vesting Schedule	3 equal annual installments commencing on October 20, 2014
May 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	17,500
Estimated Forfeiture Rate	8.90%
Vesting Schedule	3 equal annual installments commencing on October 20, 2014
September 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	30,000
Estimated Forfeiture Rate	10.40%
Vesting Schedule	3 equal annual installments commencing on October 20, 2014