INCOME TAXES: (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Federal:
Currently payable	$ 15,514	$ 9,890	$ 9,388
Deferred	1,326	(774)	2,120
Federal income tax expense (benefit), continuing operations	16,840	9,116	11,508
State:
Currently payable	2,857	1,426	1,928
Deferred	186	(150)	753
State and local income tax expense (benefit), continuing operations	3,043	1,276	2,681
TOTAL	$ 19,883	$ 10,392	$ 14,189