Stock Incentive Plans - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended							9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jun. 16, 2009	Sep. 30, 2013 Parkvale Financial Corporation [Member]	Jan. 02, 2012 Parkvale Financial Corporation [Member]	Sep. 30, 2013 Annapolis Bancorp, Inc. [Member]	Apr. 06, 2013 Annapolis Bancorp, Inc. [Member]	Sep. 30, 2013 Service-Based Awards [Member]	Sep. 30, 2013 Performance-Based Awards [Member]	Sep. 30, 2013 Discretionary Service-Based Awards [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2013 Employee Stock Option [Member]	Sep. 30, 2012 Employee Stock Option [Member]	Sep. 30, 2013 Warrant Expires In 2019 [Member]	Apr. 06, 2013 Warrant Expires In 2019 [Member] Annapolis Bancorp, Inc. [Member]	Sep. 30, 2013 Warrant Expires in 2018 [Member] Parkvale Financial Corporation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards issued	344,479	275,674
Aggregate, weighted average grant date fair value	$ 3,802	$ 3,384
Common stock shares available under Incentive Compensation Plans	2,734,087
Vesting period of awards expensed, years								3 years	4 years	5 years			10 years
Share-based compensation expense related to restricted stock awards											$ 3,338	$ 2,634
Tax benefit related to restricted stock awards											1,186	922
Total fair value of awards vested											8,259	2,068
Unrecognized compensation cost related to unvested restricted stock awards	5,786										5,786
Amount subject to accelerated vesting under Incentive Compensation Plan											90
Stock options exercised	36,647	174,565											36,647	174,565
Stock options granted
Intrinsic value of outstanding and exercisable stock options	$ 217
Maximum common shares available for purchase under warrants	1,302,083		651,042
Warrant issued, exercise price					5.81		3.57								11.52	3.57	5.81
Warrant issued				819,640		342,564