Share-Based Payments and Employee Benefits - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended	1 Months Ended					9 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended	9 Months Ended	1 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Maximum	Sep. 30, 2013 Minimum	Sep. 30, 2013 Restricted Stock	Sep. 30, 2012 Restricted Stock	Sep. 30, 2013 Restricted Stock	Sep. 30, 2012 Restricted Stock	Dec. 31, 2012 Restricted Stock	Sep. 30, 2013 Restricted Stock Maximum	Aug. 08, 2013 Board Restricted Stock	Jun. 05, 2013 Board Restricted Stock	May 03, 2013 Board Restricted Stock	Jan. 31, 2013 Board Restricted Stock	Aug. 06, 2012 Board Restricted Stock	Sep. 30, 2013 Board Restricted Stock January 1, 2014	Aug. 08, 2013 Board Restricted Stock January 1, 2014	Jun. 05, 2013 Board Restricted Stock January 1, 2014	Sep. 30, 2013 Stock Options	Sep. 30, 2012 Stock Options	Sep. 30, 2013 Stock Options	Sep. 30, 2012 Stock Options	Dec. 31, 2012 Stock Options	Sep. 30, 2013 Stock Options Maximum	Jun. 05, 2013 CEO Stock Options	Sep. 30, 2013 CEO Stock Options	Sep. 30, 2013 CEO Stock Options First Options	Sep. 30, 2013 CEO Stock Options Remaining Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate grant date fair value per nonexecutive director	$ 75,000		$ 75,000
Restricted common stock awards, vesting period													5 years														4 years
Shares of restricted stock that vested early																		111,112
Restricted shares granted										128,134		321,033		2,481	25,000	25,000	18,293
Grant date value of restricted stock award																138,750				69,454	167,500
Vesting date of the shares granted																			Jan. 01, 2014
Compensation expenses for share-based awards			1,503,000	1,210,000				300,000	300,000	900,000	700,000											300,000	100,000	600,000	500,000
Unrecognized share-based compensation expense								500,000		500,000		700,000										900,000		900,000
Unrecognized share-based compensation expense weighted average contractual term										10 months 24 days		1 year 7 months 6 days												1 year 2 months 12 days
Common stock options term						10 years	8 years
Grant date fair value per share	$ 2.75		$ 2.75		$ 1.67
Options granted			205,000		184,600																							200,000		50,000	150,000
Percentage of options that vest every six months																													0.25
Exercise price																														$ 8.50	$ 10.00
Grant date fair value of options granted																													549,714
Options outstanding weighted average remaining contractual life (in years)																								7 years 9 months 18 days		8 years 7 months 6 days
Options exercisable weighted average remaining contractual life (in years)																								7 years 9 months 18 days
Percentage of company match of employee contributions			100.00%
Percentage of employee cash compensation match			4.00%
Matching contribution	$ 41,000	$ 30,000	$ 100,000	$ 45,000
Shares authorized under the incentive plan	2,500,000		2,500,000
Shares available for grant under the incentive plan	600,000		600,000		900,000