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	34,969			34,969
Other comprehensive income (loss)	(4,752)					(4,752)
Acquisition of Community Financial Corporation	28,508		4,236		24,272
Cash dividends declared	(17,686)			(17,686)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	963		(315)		1,278
Exercise of stock options	2,766		(170)		2,936
Ending balance at Sep. 30, 2013	378,042	46,249	107,275	326,553	(95,861)	(6,174)
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	38,432			38,432
Other comprehensive income (loss)	2,069					2,069
Cash dividends declared	(18,681)			(18,681)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	1,210		(262)		1,472
Exercise of stock options	553		(272)		825
Purchase of treasury shares	(19,533)				(19,533)
Ending balance at Sep. 30, 2014	$ 391,673	$ 46,249	$ 107,062	$ 353,721	$ (112,438)	$ (2,921)