Junior Subordinated Debt - Junior Subordinated Debt Trusts (Detail) (USD $) In Thousands, unless otherwise specified			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 F.N.B. Statutory Trust I [Member]	Sep. 30, 2013 F.N.B. Statutory Trust II [Member]	Sep. 30, 2013 Omega Financial Capital Trust I [Member]	Sep. 30, 2013 Sun Bancorp Statutory Trust I [Member]	Sep. 30, 2013 Annapolis Bancorp Statutory Trust One[Member]
Subordinated Borrowing [Line Items]
Trust Preferred Securities	$ 189,000		$ 110,000	$ 21,500	$ 36,000	$ 16,500	$ 5,000
Common Securities	6,311		3,866	665	1,114	511	155
Junior subordinated debt	$ 194,213	$ 204,019	$ 113,866	$ 22,165	$ 36,016	$ 17,011	$ 5,155
Stated Maturity Date			Mar. 31, 2033	Jun. 15, 2036	Oct. 18, 2034	Feb. 22, 2031	Mar. 26, 2033
Interest Rate			3.52%	1.90%	2.46%	10.20%	3.40%
Description of variable rate			Variable; LIBOR + 325 basis points (bps)	Variable; LIBOR + 165 bps	Variable; LIBOR + 219 bps	Fixed	Variable; LIBOR + 315 bps
Basis points			3.25%	1.65%	2.19%		3.15%