Quarterly Unaudited Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Unaudited Financial Data [Abstract]
Total Interest Income	$ 36,799	$ 34,065	$ 32,161	$ 30,428	$ 29,692	$ 29,609	$ 28,069	$ 27,242	$ 133,453	$ 114,612	$ 99,266
Total Interest Expense	2,611	2,157	1,660	1,522	1,616	1,759	1,538	1,376	7,950	6,289	4,196
Net Interest Income	34,188	31,908	30,501	28,906	28,076	27,850	26,531	25,866	125,503	108,323	95,070
Provision for Credit Losses	2,200	2,500	500	333	0	1,600	650	600	5,533	2,850	6,335
Net Interest Income After Provision for Credit Losses	31,988	29,408	30,001	28,573	28,076	26,250	25,881	25,266	119,970	105,473	88,735
Total Non-Interest Income	4,063	4,208	2,283	4,665	4,179	3,638	3,539	5,406	15,219	16,762	15,257
Total Non-Interest Expense	18,757	18,621	18,145	19,936	16,500	16,307	16,525	18,422	75,459	67,754	58,172
Income Before Income Taxes	17,294	14,995	14,139	13,302	15,755	13,581	12,895	12,250	59,730	54,481	45,820
Provision for Income Taxes	4,258	2,995	3,589	3,361	11,974	5,000	4,708	4,429	14,203	26,111	16,097
Net Income	$ 13,036	$ 12,000	$ 10,550	$ 9,941	$ 3,781	$ 8,581	$ 8,187	$ 7,821	$ 45,527	$ 28,370	$ 29,723
Basic Earnings Per Common Share (in dollars per share)	$ 16.56	$ 15.12	$ 12.90	$ 12.24	$ 4.64	$ 10.59	$ 10.12	$ 9.68	$ 56.82	$ 35.03	$ 37.44