ALLOWANCE FOR LOAN LOSSES: (Details 1) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Ending Balance Attributable to Loans
Individually evaluated for impairment	$ 1,159	$ 1,911
Collectively evaluated for impairment	18,600	16,648
BALANCE AT END OF YEAR	19,946	18,839	$ 20,068	$ 21,958
Loans
Individually evaluated for impairment	9,725	14,606
Collectively evaluated for impairment	1,754,444	1,767,701
BALANCE AT END OF YEAR	1,769,790	1,788,825
Commercial
Ending Balance Attributable to Loans
Individually evaluated for impairment	953	1,911
Collectively evaluated for impairment	10,342	8,733
BALANCE AT END OF YEAR	11,482	10,915	12,450	10,987
Loans
Individually evaluated for impairment	8,823	14,573
Collectively evaluated for impairment	1,037,086	1,030,949
BALANCE AT END OF YEAR	1,050,001	1,050,409
Residential
Ending Balance Attributable to Loans
Individually evaluated for impairment	206	0
Collectively evaluated for impairment	1,628	1,365
BALANCE AT END OF YEAR	1,834	1,374	1,585	5,426
Loans
Individually evaluated for impairment	902	33
Collectively evaluated for impairment	443,224	468,872
BALANCE AT END OF YEAR	445,655	470,536
Consumer
Ending Balance Attributable to Loans
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	4,945	4,370
BALANCE AT END OF YEAR	4,945	4,370	3,650	3,879
Loans
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	274,134	267,880
BALANCE AT END OF YEAR	274,134	267,880
Unallocated
Ending Balance Attributable to Loans
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,685	2,180
BALANCE AT END OF YEAR	1,685	2,180	$ 2,383	$ 1,666
Acquired with deteriorated credit quality
Ending Balance Attributable to Loans
Acquired with deteriorated credit quality	187	280
Loans
Acquired with deteriorated credit quality	5,621	6,518
Acquired with deteriorated credit quality | Commercial
Ending Balance Attributable to Loans
Acquired with deteriorated credit quality	187	271
Loans
Acquired with deteriorated credit quality	4,092	4,887
Acquired with deteriorated credit quality | Residential
Ending Balance Attributable to Loans
Acquired with deteriorated credit quality	0	9
Loans
Acquired with deteriorated credit quality	1,529	1,631
Acquired with deteriorated credit quality | Consumer
Ending Balance Attributable to Loans
Acquired with deteriorated credit quality	0	0
Loans
Acquired with deteriorated credit quality	0	0
Acquired with deteriorated credit quality | Unallocated
Ending Balance Attributable to Loans
Acquired with deteriorated credit quality	$ 0	$ 0