ALLOWANCE FOR LOAN LOSSES: (Details 5) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	$ 21,305	$ 15,501
Current	1,891,717	1,829,539
BALANCE AT END OF YEAR	1,913,022	1,845,040
Commercial & Industrial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	1,092	1,683
Current	474,709	474,406
BALANCE AT END OF YEAR	475,801	476,089
Farmland
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	4,012	303
Current	104,457	110,897
BALANCE AT END OF YEAR	108,469	111,200
Non Farm, Non Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	141	368
Current	200,804	195,120
BALANCE AT END OF YEAR	200,945	195,488
Agriculture
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	702	713
Current	152,388	151,059
BALANCE AT END OF YEAR	153,090	151,772
All Other Commercial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	15
Current	207,875	178,171
BALANCE AT END OF YEAR	207,875	178,186
First Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	8,218	6,332
Current	247,029	264,446
BALANCE AT END OF YEAR	255,247	270,778
Home Equity
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	364	277
Current	35,752	35,782
BALANCE AT END OF YEAR	36,116	36,059
Junior Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	574	495
Current	41,688	36,912
BALANCE AT END OF YEAR	42,262	37,407
Multifamily
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
Current	90,141	67,799
BALANCE AT END OF YEAR	90,141	67,799
All Other Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	312	54
Current	13,329	12,982
BALANCE AT END OF YEAR	13,641	13,036
Motor Vehicle
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	5,761	5,093
Current	298,211	277,604
BALANCE AT END OF YEAR	303,972	282,697
All Other Consumer
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	129	168
Current	25,334	24,361
BALANCE AT END OF YEAR	25,463	24,529
30 to 59 Days Past Due
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	12,223	9,571
30 to 59 Days Past Due | Commercial & Industrial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	372	370
30 to 59 Days Past Due | Farmland
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	341	235
30 to 59 Days Past Due | Non Farm, Non Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	141	153
30 to 59 Days Past Due | Agriculture
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	141	246
30 to 59 Days Past Due | All Other Commercial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	15
30 to 59 Days Past Due | First Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	5,467	3,862
30 to 59 Days Past Due | Home Equity
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	310	186
30 to 59 Days Past Due | Junior Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	274	271
30 to 59 Days Past Due | Multifamily
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
30 to 59 Days Past Due | All Other Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	300	42
30 to 59 Days Past Due | Motor Vehicle
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	4,770	4,048
30 to 59 Days Past Due | All Other Consumer
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	107	143
60 to 89 Days Past Due
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	2,268	1,920
60 to 89 Days Past Due | Commercial & Industrial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	80	114
60 to 89 Days Past Due | Farmland
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	22
60 to 89 Days Past Due | Non Farm, Non Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
60 to 89 Days Past Due | Agriculture
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
60 to 89 Days Past Due | All Other Commercial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
60 to 89 Days Past Due | First Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	1,317	954
60 to 89 Days Past Due | Home Equity
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	46	64
60 to 89 Days Past Due | Junior Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	106	0
60 to 89 Days Past Due | Multifamily
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
60 to 89 Days Past Due | All Other Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	12
60 to 89 Days Past Due | Motor Vehicle
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	697	732
60 to 89 Days Past Due | All Other Consumer
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	22	22
Greater than 90 Days Past Due
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	6,814	4,010
Greater than 90 Days Past Due | Commercial & Industrial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	640	1,199
Greater than 90 Days Past Due | Farmland
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	3,671	46
Greater than 90 Days Past Due | Non Farm, Non Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	215
Greater than 90 Days Past Due | Agriculture
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	561	467
Greater than 90 Days Past Due | All Other Commercial
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
Greater than 90 Days Past Due | First Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	1,434	1,516
Greater than 90 Days Past Due | Home Equity
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	8	27
Greater than 90 Days Past Due | Junior Liens
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	194	224
Greater than 90 Days Past Due | Multifamily
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	0	0
Greater than 90 Days Past Due | All Other Residential
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	12	0
Greater than 90 Days Past Due | Motor Vehicle
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	294	313
Greater than 90 Days Past Due | All Other Consumer
Aging of recorded investment in loans by past due category and class of loans
Total Past Due	$ 0	$ 3