PARENT COMPANY CONDENSED FINANCIAL STATEMENTS: (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 657,470	$ 127,426
Land and headquarters building, net	62,063	62,576
Other assets	37,530	41,556
TOTAL ASSETS	4,557,544	4,023,250
LIABILITIES AND SHAREHOLDERS’ EQUITY
Other liabilities	82,687	79,193
TOTAL LIABILITIES	3,960,552	3,465,642
Shareholders' Equity	596,992	557,608	$ 442,701	$ 413,569
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	4,557,544	4,023,250
Parent
ASSETS
Cash and due from banks	2,480	4,394
Investments in subsidiaries	597,888	566,384
Land and headquarters building, net	4,614	4,807
Other assets	6,000	23
TOTAL ASSETS	610,982	575,608
LIABILITIES AND SHAREHOLDERS’ EQUITY
Dividends payable	7,182	7,142
Other liabilities	6,808	681
TOTAL LIABILITIES	13,990	18,000
Shareholders' Equity	596,992	557,608
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 610,982	$ 575,608