Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total	Series A 3% Preferred Stock [Member]	Series B-1 8.48% Preferred Stock [Member]	Preferred Equity [Member]	Preferred Equity [Member] Series A 3% Preferred Stock [Member]	Preferred Equity [Member] Series B-1 8.48% Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Series A 3% Preferred Stock [Member]	Retained Earnings [Member]	Retained Earnings [Member] Series A 3% Preferred Stock [Member]	Retained Earnings [Member] Series B-1 8.48% Preferred Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2015	$ 293,844			$ 17,340			$ 144	$ 72,690		$ 218,920			$ (11,327)	$ (3,923)
Comprehensive income:
Net income	31,931									31,931
Other comprehensive income (loss), net of tax	(2,624)												(2,624)
Common stock issued	8,100						3	8,097
Share-based compensation plans:
Share-based compensation	845							845
Stock options exercised	964							23						941
Restricted stock awards issued, net								24						(24)
Excess tax benefit	30							30
Stock awards	128							46						82
Cash dividends declared:
Preferred stock dividends per share		$ (4)	$ (1,458)								$ (4)	$ (1,458)
Common stock dividends per share	(11,702)									(11,702)
Balance at Dec. 31, 2016	320,054			17,340			147	81,755		237,687			(13,951)	(2,924)
Adjusted Balance at Dec. 31, 2016	320,054			17,340			147	81,476		237,966			(13,951)	(2,924)
Cumulative-effect adjustment								(279)		279
Comprehensive income:
Net income	33,526									33,526
Other comprehensive income (loss), net of tax	2,035												2,035
Common stock issued	38,303						14	38,289
Purchase of common stock for treasury	(148)													(148)
Repurchase of preferred stock		(3)	(6)		$ (5)	$ (6)			$ 2
Share-based compensation plans:
Share-based compensation	1,174							1,174
Stock options exercised	413							5						408
Restricted stock awards issued, net								21						(21)
Stock awards	243							91						152
Cash dividends declared:
Preferred stock dividends per share		(4)	(1,458)								(4)	(1,458)
Common stock dividends per share	(12,952)									(12,952)
Balance at Dec. 31, 2017	381,177			17,329			161	121,058		257,078			(11,916)	(2,533)
Comprehensive income:
Net income	39,526									39,526
Other comprehensive income (loss), net of tax	(9,365)												(9,365)
Purchase of common stock for treasury	(113)													(113)
Repurchase of preferred stock		(1)			$ (1)
Share-based compensation plans:
Share-based compensation	1,301							1,301
Stock options exercised	320							(19)						339
Restricted stock awards issued, net								303						(303)
Stock awards	185							61						124
Cash dividends declared:
Preferred stock dividends per share		$ (4)	$ (1,457)								$ (4)	$ (1,457)
Common stock dividends per share	(15,276)									(15,276)
Balance at Dec. 31, 2018	$ 396,293			$ 17,328			$ 161	$ 122,704		$ 279,867			$ (21,281)	$ (2,486)