Consolidated Statements Of Changes In Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Capital Surplus[Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2012	$ 333,274	$ 46,249	$ 103,524	$ 309,270	$ (124,347)	$ (1,422)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,993			20,993
Other comprehensive income (loss)	(4,118)					(4,118)
Acquisition of Community Financial Corporation	28,508		4,236		24,272
Cash dividends declared	(11,866)			(11,866)
Stock-based compensation expense, net	703		(512)		1,215
Exercise of stock options	1,397		(13)		1,410
Ending balance at Jun. 30, 2013	368,891	46,249	107,235	318,397	(97,450)	(5,540)
Beginning Balance at Dec. 31, 2013	387,623	46,249	107,596	333,970	(95,202)	(4,990)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	26,560			26,560
Other comprehensive income (loss)	2,481					2,481
Cash dividends declared	(12,512)			(12,512)
Stock-based compensation expense, net	889		(494)		1,383
Exercise of stock options	553		(272)		825
Purchase of treasury shares	(8,363)				(8,363)
Ending balance at Jun. 30, 2014	$ 397,231	$ 46,249	$ 106,830	$ 348,018	$ (101,357)	$ (2,509)