SELECTED QUARTERLY DATA (UNAUDITED) (Summary Of Selected Quarterly Data) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SELECTED QUARTERLY DATA (UNAUDITED
Interest income	$ 49,854	$ 45,979	$ 46,831	$ 50,439	$ 52,312	$ 54,769	$ 54,635	$ 53,494	$ 193,103	$ 215,210	$ 198,970
Interest expense	5,141	6,066	7,303	11,585	13,430	15,224	16,224	15,285	30,095	60,163	47,699
Net interest income	44,713	39,913	39,528	38,854	38,882	39,545	38,411	38,209	163,008	155,047	151,271
Provision for loan losses	920	1,750	5,500	6,600	250	1,000	785	1,200	14,770	3,235	6,400
Net interest income after provision	43,793	38,163	34,028	32,254	38,632	38,545	37,626	37,009	148,238	151,812	144,871
Noninterest income	11,782	13,115	11,169	10,777	11,119	10,765	11,588	11,525
Noninterest expense	24,912	23,125	21,079	22,089	22,122	22,737	22,092	22,473	91,205	89,424	86,229
Income tax expense	6,071	5,377	4,448	3,643	5,431	5,119	5,409	4,379	19,539	20,338	18,533
Net income	$ 24,592	$ 22,776	$ 19,670	$ 17,299	$ 22,198	$ 21,454	$ 21,713	$ 21,682	$ 84,337	$ 87,047	$ 80,411
Basic earnings per common share	$ 0.97	$ 0.89	$ 0.77	$ 0.68	$ 0.86	$ 0.84	$ 0.85	$ 0.85	$ 3.31	$ 3.40	$ 3.18
Diluted earnings per common share	$ 0.97	$ 0.89	$ 0.77	$ 0.67	$ 0.86	$ 0.83	$ 0.85	$ 0.84	$ 3.30	$ 3.38	$ 3.13