Mergers And Acquisitions (Narrative) (Detail) (USD $) In Thousands, except Share data, unless otherwise specified				9 Months Ended
	Sep. 30, 2012	Dec. 31, 2010	Dec. 31, 2010 Comm Bancorp, Inc. [Member]	Sep. 30, 2012 Parkvale Financial Corporation [Member]	Sep. 30, 2012 Annapolis Bancorp, Inc. [Member] Ratio
Business Acquisition [Line Items]
Assets acquired as a result of merger			$ 625,570	$ 1,815,663
Loans acquired as a result of merger	919,479		445,271	937,350
Deposits acquired as a result of merger	1,525,253		561,775	1,505,671
Value of acquisition			75,547	140,900	51,000
Common stock issued for exchange in merger	12,159,312	5,941,287	1,719,978	5,582,846
Value of preferred stock repaid				31,762
Warrants converted to purchase of common stock	819,640			819,640
Warrant, expiration date				Dec. 23, 2018
Warrants, exercise price				$ 5.81
Goodwill recorded as a result of merger	108,216		40,232	108,216
Core deposit intangible recorded as a result of merger			4,785	16,033
Merger and integration charges				7,399
Cash paid for acquisition of CBI			17,203
Bank holding company in total assets					$ 437,000
Exchange ratio					1.143
Contingent cash payment per share					$ 0.36