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]
Cumulative Effect of New Accounting Principle in Period of Adoption | Adjustments for New Accounting Pronouncement [Member]				$ 3,806		$ (3,806)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 995					3,806
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets | Accounting Standards Update 2016-01 [Member]				(1,917)		995
Balance at Dec. 31, 2017		$ 0	$ 307,726	561,908	$ (87,079)	(26,454)
Balance (Accounting Standards Update 2016-01 [Member]) at Dec. 31, 2017		0	307,726	563,825	(87,079)	(27,449)
Net Income				31,123
Other comprehensive income (loss)						(21,386)
Dividends on common shares				(14,496)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			(1,597)	(317)	(1,304)
Share-based Payment Arrangement, Expense			1,121
Balance at Mar. 31, 2018		0	307,249	583,941	(85,775)	(52,641)
Balance at Dec. 31, 2017		0	307,726	561,908	(87,079)	(26,454)
Balance (Accounting Standards Update 2016-01 [Member]) at Dec. 31, 2017		0	307,726	563,825	(87,079)	(27,449)
Net Income	84,126
Other comprehensive income (loss)	(28,895)
Share-based Payment Arrangement, Expense	3,100
Balance at Sep. 30, 2018		0	357,709	603,091	(91,559)	(60,150)
Balance at Mar. 31, 2018		0	307,249	583,941	(85,775)	(52,641)
Net Income				28,241
Other comprehensive income (loss)						(2,368)
Dividends on common shares				(18,670)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Share-based Payment Arrangement, Expense			896
Treasury Stock, Value, Acquired, Cost Method					5,784
Balance at Jun. 30, 2018		0	308,144	593,512	(91,559)	(55,009)
Net Income	24,762			24,762
Other comprehensive income (loss)	(5,141)					(5,141)
Dividends on common shares				(15,183)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Share-based Payment Arrangement, Expense	1,000		1,047
Proceeds from Issuance of Common Stock			48,519
Balance at Sep. 30, 2018		0	357,709	603,091	(91,559)	(60,150)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				143
Balance at Dec. 31, 2018	832,506	0	358,598	614,069	(90,373)	(49,788)
Balance (Adjustments for New Accounting Pronouncement [Member]) at Dec. 31, 2018				613,926
Net Income				25,455
Other comprehensive income (loss)						14,335
Dividends on common shares				(19,137)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures			(2,480)	(273)	(1,926)
Share-based Payment Arrangement, Expense			1,358
Treasury Stock, Value, Acquired, Cost Method					8,502
Balance at Mar. 31, 2019		0	357,475	619,971	(96,949)	(35,453)
Balance at Dec. 31, 2018	832,506	0	358,598	614,069	(90,373)	(49,788)
Balance (Adjustments for New Accounting Pronouncement [Member]) at Dec. 31, 2018				613,926
Net Income	78,764
Other comprehensive income (loss)	37,174
Share-based Payment Arrangement, Expense	3,800
Balance at Sep. 30, 2019	956,140	0	458,142	639,594	(128,982)	(12,614)
Balance at Mar. 31, 2019		0	357,475	619,971	(96,949)	(35,453)
Net Income				22,163
Other comprehensive income (loss)						9,146
Dividends on common shares				(16,907)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Share-based Payment Arrangement, Expense			1,162
Treasury Stock, Value, Acquired, Cost Method					24,450
Proceeds from Issuance of Common Stock			98,275
Balance at Jun. 30, 2019		0	456,911	625,227	(121,399)	(26,307)
Net Income	31,146			31,146
Other comprehensive income (loss)	13,693					13,693
Dividends on common shares				(16,779)
Cash payment for fractional shares in dividend reinvestment plan			(1)
Share-based Payment Arrangement, Expense	1,200		1,232
Treasury Stock, Value, Acquired, Cost Method					7,583
Balance at Sep. 30, 2019	$ 956,140	$ 0	$ 458,142	$ 639,594	$ (128,982)	$ (12,614)