INVESTMENT SECURITIES (Tables)
   | 
12 Months Ended | 
Dec. 31, 2019  | 
| Investments, Debt and Equity Securities [Abstract] | 
 
 | 
| Schedule of amortized cost and related market value of investment securities available-for-sale | 
| Note 2 |  
| INVESTMENT SECURITIES | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| 
Investment Portfolio Composition. The amortized cost and related market value of investment securities available-for-sale and 
 |  
| held-to-maturity were as follows: |  
 | 
2019 | 
 | 
 | 
2018 | 
 
 | 
Amortized | 
 | 
Unrealized | 
Unrealized | 
Market | 
 | 
Amortized | 
 | 
Unrealized | 
Unrealized | 
Market | 
 
| (Dollars in Thousands) | 
Cost | 
 | 
Gains | 
 | 
Losses | 
 | 
Value | 
 | 
Cost | 
 | 
Gain | 
 | 
Losses | 
 | 
Value | 
 
| Available for Sale | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| U.S. Government Treasury | 
$ | 
231,996 | 
 | 
$ | 
849 | 
 | 
$ | 
67 | 
 | 
$ | 
232,778 | 
 | 
$ | 
264,298 | 
 | 
$ | 
167 | 
 | 
$ | 
2,616 | 
 | 
$ | 
261,849 | 
 
| U.S. Government Agency | 
 | 
155,706 | 
 | 
 | 
697 | 
 | 
 | 
325 | 
 | 
 | 
156,078 | 
 | 
 | 
133,201 | 
 | 
 | 
520 | 
 | 
 | 
515 | 
 | 
 | 
133,206 | 
 
| States and Political Subdivisions | 
 | 
6,310 | 
 | 
 | 
9 | 
 | 
 | 
- | 
 | 
 | 
6,319 | 
 | 
 | 
42,509 | 
 | 
 | 
- | 
 | 
 | 
144 | 
 | 
 | 
42,365 | 
 
| Mortgage-Backed Securities | 
 | 
693 | 
 | 
 | 
80 | 
 | 
 | 
- | 
 | 
 | 
773 | 
 | 
 | 
903 | 
 | 
 | 
40 | 
 | 
 | 
- | 
 | 
 | 
943 | 
 
| 
Equity Securities(1)
 | 
 | 
7,653 | 
 | 
 | 
- | 
 | 
 | 
- | 
 | 
 | 
7,653 | 
 | 
 | 
7,794 | 
 | 
 | 
- | 
 | 
 | 
- | 
 | 
 | 
7,794 | 
 
| Total  | 
$ | 
402,358 | 
 | 
$ | 
1,635 | 
 | 
$ | 
392 | 
 | 
$ | 
403,601 | 
 | 
$ | 
448,705 | 
 | 
$ | 
727 | 
 | 
$ | 
3,275 | 
 | 
$ | 
446,157 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Held to Maturity | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| U.S. Government Treasury | 
$ | 
20,036 | 
 | 
$ | 
15 | 
 | 
$ | 
9 | 
 | 
$ | 
20,042 | 
 | 
$ | 
35,088 | 
 | 
$ | 
- | 
 | 
$ | 
477 | 
 | 
$ | 
34,611 | 
 
| States and Political Subdivisions | 
 | 
1,376 | 
 | 
 | 
- | 
 | 
 | 
- | 
 | 
 | 
1,376 | 
 | 
 | 
6,512 | 
 | 
 | 
- | 
 | 
 | 
26 | 
 | 
 | 
6,486 | 
 
| Mortgage-Backed Securities | 
 | 
218,127 | 
 | 
 | 
2,064 | 
 | 
 | 
180 | 
 | 
 | 
220,011 | 
 | 
 | 
175,720 | 
 | 
 | 
220 | 
 | 
 | 
2,624 | 
 | 
 | 
173,316 | 
 
| Total  | 
$ | 
239,539 | 
 | 
$ | 
2,079 | 
 | 
$ | 
189 | 
 | 
$ | 
241,429 | 
 | 
$ | 
217,320 | 
 | 
$ | 
220 | 
 | 
$ | 
3,127 | 
 | 
$ | 
214,413 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Total Investment Securities | 
$ | 
641,897 | 
 | 
$ | 
3,714 | 
 | 
$ | 
581 | 
 | 
$ | 
645,030 | 
 | 
$ | 
666,025 | 
 | 
$ | 
947 | 
 | 
$ | 
6,402 | 
 | 
$ | 
660,570 | 
 
  
(1) 	Includes Federal Home Loan Bank and Federal Reserve Bank recorded at cost of $2.9 million and $4.8 million, respectively, at December 31, 2019 and Federal Home Loan Bank and Federal Reserve Bank recorded at cost of $3.0 million and $4.8 million, respectively, at December 31, 2018. 
 
 | 
| Schedule of investment securities with maturity distribution based on contractual maturities | 
 | 
Available for Sale | 
 | 
Held to Maturity | 
 
 | 
Amortized | 
   | 
Market  | 
   | 
Amortized | 
   | 
Market | 
 
| (Dollars in Thousands) | 
Cost | 
 | 
Value | 
 | 
Cost | 
 | 
Value | 
 
| Due in one year or less | 
$ | 
134,339 | 
   | 
$ | 
134,331 | 
   | 
$ | 
16,406 | 
   | 
$ | 
16,397 | 
 
| Due after one through five years | 
   | 
103,967 | 
   | 
   | 
104,766 | 
   | 
   | 
5,006 | 
   | 
   | 
5,021 | 
 
| Mortgage-Backed Securities | 
 | 
693 | 
 | 
 | 
773 | 
 | 
 | 
218,127 | 
 | 
 | 
220,011 | 
 
| U.S. Government Agency | 
   | 
155,706 | 
   | 
   | 
156,078 | 
   | 
   | 
- | 
   | 
   | 
- | 
 
| Equity Securities | 
   | 
7,653 | 
   | 
   | 
7,653 | 
   | 
   | 
- | 
   | 
   | 
- | 
 
| Total  | 
$ | 
402,358 | 
   | 
$ | 
403,601 | 
   | 
$ | 
239,539 | 
   | 
$ | 
241,429 | 
 
  
 | 
| Schedule of investment securities with continuous unrealized loss position | 
 | 
Less Than 12 Months | 
 | 
Greater Than 12 Months | 
 | 
Total | 
 
 | 
Market | 
 | 
Unrealized | 
 | 
Market | 
 | 
Unrealized | 
 | 
Market | 
 | 
Unrealized | 
 
| (Dollars in Thousands) | 
Value | 
 | 
Losses | 
 | 
Value | 
 | 
Losses | 
 | 
Value | 
 | 
Losses | 
 
| December 31, 2019 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Available for Sale | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| U.S. Government Treasury | 
$ | 
9,955 | 
   | 
$ | 
- | 
   | 
$ | 
93,310 | 
   | 
$ | 
67 | 
   | 
$ | 
103,265 | 
   | 
$ | 
67 | 
 
| U.S. Government Agency | 
 | 
36,361 | 
 | 
 | 
244 | 
 | 
 | 
17,364 | 
 | 
 | 
81 | 
 | 
 | 
53,725 | 
 | 
 | 
325 | 
 
| States and Political Subdivisions | 
 | 
578 | 
   | 
 | 
- | 
   | 
 | 
- | 
   | 
 | 
- | 
   | 
 | 
578 | 
   | 
 | 
- | 
 
| Mortgage-Backed Securities | 
   | 
8 | 
   | 
   | 
- | 
   | 
   | 
- | 
   | 
   | 
- | 
   | 
   | 
8 | 
   | 
   | 
- | 
 
| Total  | 
 | 
46,902 | 
   | 
 | 
244 | 
   | 
 | 
110,674 | 
   | 
 | 
148 | 
   | 
 | 
157,576 | 
   | 
 | 
392 | 
 
|      | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Held to Maturity | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| U.S. Government Treasury | 
   | 
- | 
   | 
 | 
- | 
   | 
  | 
15,022 | 
   | 
 | 
9 | 
   | 
  | 
15,022 | 
   | 
   | 
9 | 
 
| States and Political Subdivisions | 
 | 
1,033 | 
 | 
 | 
- | 
 | 
 | 
- | 
 | 
 | 
- | 
 | 
 | 
1,033 | 
 | 
 | 
- | 
 
| Mortgage-Backed Securities | 
   | 
22,581 | 
   | 
   | 
42 | 
   | 
   | 
16,027 | 
   | 
   | 
138 | 
   | 
   | 
38,608 | 
   | 
   | 
180 | 
 
| Total  | 
$ | 
23,614 | 
   | 
$ | 
42 | 
   | 
$ | 
31,049 | 
   | 
$ | 
147 | 
   | 
$ | 
54,663 | 
   | 
$ | 
189 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| December 31, 2018 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Available for Sale  | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| U.S. Government Treasury | 
$ | 
28,420 | 
   | 
$ | 
80 | 
   | 
$ | 
193,501 | 
   | 
$ | 
2,536 | 
   | 
$ | 
221,921 | 
   | 
$ | 
2,616 | 
 
| U.S. Government Agency | 
 | 
53,237 | 
 | 
 | 
271 | 
 | 
 | 
28,735 | 
 | 
 | 
244 | 
 | 
 | 
81,972 | 
 | 
 | 
515 | 
 
| States and Political Subdivisions | 
   | 
8,243 | 
   | 
   | 
12 | 
   | 
   | 
31,417 | 
   | 
   | 
132 | 
   | 
   | 
39,660 | 
   | 
   | 
144 | 
 
| Mortgage-Backed Securities | 
 | 
10 | 
 | 
 | 
- | 
 | 
 | 
- | 
 | 
 | 
- | 
 | 
 | 
10 | 
 | 
 | 
- | 
 
| Total  | 
 | 
89,910 | 
   | 
 | 
363 | 
   | 
 | 
253,653 | 
   | 
 | 
2,912 | 
   | 
 | 
343,563 | 
   | 
 | 
3,275 | 
 
|      | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Held to Maturity | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| U.S. Government Treasury | 
   | 
- | 
   | 
   | 
- | 
   | 
   | 
34,612 | 
   | 
   | 
477 | 
   | 
   | 
34,612 | 
   | 
   | 
477 | 
 
| States and Political Subdivisions | 
 | 
204 | 
 | 
 | 
- | 
 | 
 | 
6,281 | 
 | 
 | 
26 | 
 | 
 | 
6,485 | 
 | 
 | 
26 | 
 
| Mortgage-Backed Securities | 
 | 
51,327 | 
 | 
 | 
389 | 
 | 
 | 
84,705 | 
 | 
 | 
2,235 | 
 | 
 | 
136,032 | 
 | 
 | 
2,624 | 
 
| Total  | 
$ | 
51,531 | 
   | 
$ | 
389 | 
   | 
$ | 
125,598 | 
   | 
$ | 
2,738 | 
   | 
$ | 
177,129 | 
   | 
$ | 
3,127 | 
 
  
 |