PARENT COMPANY STATEMENTS (CONDENSED STATEMENTS OF CASH FLOWS) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 11,627	$ 15,825	$ 15,364	$ 14,514	$ 13,522	$ 13,480	$ 12,803	$ 12,279	$ 57,330	$ 52,084	$ 46,367
Adjustments to net cash from operating activities:
Net cash from operating activities									77,242	62,199	55,781
Cash flows from financing activities
Purchase of treasury stock									(495)	(458)	(455)
Cash flows from financing activities									327,708	466,855	273,362
Net increase in cash and cash equivalents									8,900	86,606	(9,964)
Cash and cash equivalents at beginning of the year				167,280				80,674	167,280	80,674	90,638
Cash and cash equivalents at end of the year	176,180				167,280				176,180	167,280	80,674
Parent Company [Member]
Cash flows from operating activities:
Net income									57,330	52,084	46,367
Adjustments to net cash from operating activities:
Equity in undistributed income of subsidiaries									(39,573)	(34,090)	(37,620)
Other changes									3,586	3,818	3,647
Net cash from operating activities									21,343	21,812	12,394
Cash flows from financing activities
Payments (Proceeds) from issuance of common stock									(1,736)	614	12
Purchase of treasury stock									(495)	(458)	(455)
Dividends paid									(21,396)	(18,200)	(15,697)
Cash flows from financing activities									(23,627)	(18,044)	(16,140)
Net increase in cash and cash equivalents									(2,284)	3,768	(3,746)
Cash and cash equivalents at beginning of the year				$ 8,103				$ 4,335	8,103	4,335	8,081
Cash and cash equivalents at end of the year	$ 5,819				$ 8,103				$ 5,819	$ 8,103	$ 4,335