LOANS: (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	$ 2,652,530	$ 1,951,063
Deferred costs, net	3,860	2,925
Allowance for loan losses	(19,943)	(20,436)	$ (19,909)	$ (18,773)
TOTAL	2,636,447	1,933,552
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	1,584,447	1,166,352
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	682,077	443,670
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	$ 386,006	$ 341,041