ALLOWANCE FOR LOAN LOSSES: (Details 5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	$ 12,277	$ 11,705
60-89 Days Past Due	2,145	2,858
Greater than 90 days Past Due	5,987	12,977
Total Past Due	20,409	27,540
Current	1,768,416	1,773,282
BALANCE AT END OF YEAR	1,788,825	1,800,822
Commercial & Industrial
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	574	1,076
60-89 Days Past Due	416	266
Greater than 90 days Past Due	3,046	7,900
Total Past Due	4,036	9,242
Current	451,549	459,076
BALANCE AT END OF YEAR	455,585	468,318
Farmland
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater than 90 days Past Due	0	0
Total Past Due	0	0
Current	95,452	92,602
BALANCE AT END OF YEAR	95,452	92,602
Non Farm, Non Residential
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	1,528	362
60-89 Days Past Due	68	0
Greater than 90 days Past Due	202	2,042
Total Past Due	1,798	2,404
Current	232,440	239,183
BALANCE AT END OF YEAR	234,238	241,587
Agriculture
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	246	31
60-89 Days Past Due	18	32
Greater than 90 days Past Due	502	0
Total Past Due	766	63
Current	149,099	136,388
BALANCE AT END OF YEAR	149,865	136,451
All Other Commercial
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	255	50
60-89 Days Past Due	0	217
Greater than 90 days Past Due	0	188
Total Past Due	255	455
Current	115,014	108,184
BALANCE AT END OF YEAR	115,269	108,639
First Liens
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	6,011	5,594
60-89 Days Past Due	963	1,513
Greater than 90 days Past Due	1,522	1,701
Total Past Due	8,496	8,808
Current	308,068	324,141
BALANCE AT END OF YEAR	316,564	332,949
Home Equity
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	141	307
60-89 Days Past Due	33	7
Greater than 90 days Past Due	310	40
Total Past Due	484	354
Current	40,043	41,350
BALANCE AT END OF YEAR	40,527	41,704
Junior Liens
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	270	392
60-89 Days Past Due	83	170
Greater than 90 days Past Due	217	471
Total Past Due	570	1,033
Current	31,487	32,269
BALANCE AT END OF YEAR	32,057	33,302
Multifamily
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	0	103
60-89 Days Past Due	0	19
Greater than 90 days Past Due	0	400
Total Past Due	0	522
Current	72,310	66,138
BALANCE AT END OF YEAR	72,310	66,660
All Other Residential
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	112	88
60-89 Days Past Due	0	0
Greater than 90 days Past Due	5	1
Total Past Due	117	89
Current	8,961	9,169
BALANCE AT END OF YEAR	9,078	9,258
Motor Vehicle
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	3,026	3,579
60-89 Days Past Due	557	612
Greater than 90 days Past Due	180	227
Total Past Due	3,763	4,418
Current	242,406	243,146
BALANCE AT END OF YEAR	246,169	247,564
All Other Consumer
Aging of recorded investment in loans by past due category and class of loans
30-59 Days Past Due	114	123
60-89 Days Past Due	7	22
Greater than 90 days Past Due	3	7
Total Past Due	124	152
Current	21,587	21,636
BALANCE AT END OF YEAR	$ 21,711	$ 21,788