Consolidated Condensed Statements Of Changes In Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Retained Earnings [Member]	Treasury Stock At Cost [Member]	Accumulated Other Comprehensive Income (loss) [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance				$ 484,484
Cumulative Effect of New Accounting Principle in Period of Adoption				(2,057)
Balance at Dec. 31, 2014		$ 0	$ 303,104	486,541	$ (77,439)	$ (13,608)
Net Income	$ 19,044			19,044
Other comprehensive income, net of tax:
Unrealized net holding (loss) gain on securities available-for-sale, net of income taxes	7,859					7,859
Dividends on common shares at $0.94 per share				(14,488)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Allocated Share-based Compensation Expense	259		259
Treasury Stock, Value, Acquired, Cost Method					(1,783)
Balance at Mar. 31, 2015		0	303,362	489,040	(79,222)	(5,749)
Balance at Dec. 31, 2015	713,355	0	303,966	507,505	(82,473)	(15,643)
Net Income	18,686			18,686
Other comprehensive income, net of tax:
Unrealized net holding (loss) gain on securities available-for-sale, net of income taxes	11,680					11,680
Dividends on common shares at $0.94 per share				(14,487)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Allocated Share-based Compensation Expense	468		468
Balance at Mar. 31, 2016	$ 729,701	$ 0	$ 304,433	$ 511,704	$ (82,473)	$ (3,963)