PARENT COMPANY CONDENSED FINANCIAL STATEMENTS: (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash deposits in affiliated banks	$ 74,107	$ 75,012
Land and headquarters building, net	48,272	49,240
Other	30,333	37,789
TOTAL ASSETS	3,000,668	2,988,527
LIABILITIES AND SHAREHOLDERS' EQUITY
Other liabilities	70,760	64,485
TOTAL LIABILITIES	2,587,099	2,574,132
Shareholders' Equity	413,569	414,395	$ 410,316	$ 394,214
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	3,000,668	2,988,527
Parent
ASSETS
Cash deposits in affiliated banks	3,198	2,765
Investments in subsidiaries	414,839	416,024
Land and headquarters building, net	5,193	5,388
TOTAL ASSETS	423,230	424,177
LIABILITIES AND SHAREHOLDERS' EQUITY
Dividends payable	6,234	6,104
Other liabilities	3,427	3,678
TOTAL LIABILITIES	9,661	9,782
Shareholders' Equity	413,569	414,395
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 423,230	$ 424,177